Ceramic anion exchange material

Abstract

Anion exchange membranes and anion exchange materials comprising silica-based ceramics, and related methods, are provided. In some aspects, anion exchange membranes are described that comprise a silica-based ceramic forming a coating on and / or within a porous support membrane. The anion exchange membranes and anion exchange materials can have certain structural or chemical attributes (e.g., pore size / distribution, chemical functionalization) that, alone or in combination, can result in advantageous performance characteristics in any of a variety of applications where it is desirable to selectively transport positively charged ions through the membrane / material. In some embodiments, the silica-based ceramic comprises relatively small pores (e.g., substantially spherical nanometer-sized pores) that can contribute to some such advantageous characteristics. In some embodiments, the anion exchange membrane or anion exchange material comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

Description

[0001] Related Applications

[0002] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Serial No. 62 / 857,227, filed June 4, 2019, and titled “CERAMIC ANION EXCHANGE MATERIALS,” which is incorporated herein by reference in its entirety for all purposes. TECHNICAL FIELD

[0003] Ion exchange membranes and ion exchange materials, and related methods, are generally described. BACKGROUND

[0004] Anion exchange membranes and anion exchange materials are used for various industrial applications where selective transport of negatively charged ions is desired. In the case of anion exchange membranes, negatively charged ions can be selectively transported through a membrane cross section. One type of anion exchange membrane is a hydroxide ion exchange membrane, but there are anion exchange membranes that can selectively transport other types of negatively charged ions. Certain embodiments of the present disclosure relate to compositions, membranes, and materials of the invention for improving the performance and / or properties of anion exchange membranes and anion exchange materials, and related methods. SUMMARY

[0005] Anion exchange membranes and anion exchange materials comprising a silica-based ceramic, and related methods, are generally described. In some cases, the subject matter of the present invention relates to related products, alternative solutions to a particular problem, and / or multiple different uses for one or more of the systems and / or articles.

[0006] In an aspect, an anion exchange membrane is provided. In some embodiments, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coated over at least a portion of the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The average pore size of the silica-based ceramic is less than or equal to 10 nm.

[0007] In some embodiments, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic forming a coating on and / or within the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The chloride ion conductivity of the anion exchange membrane is greater than or equal to 0.00001 S / cm.

[0008] In some embodiments, the anion exchange membrane comprises a silica-based ceramic, and the anion exchange membrane has a water uptake greater than or equal to 10 wt% and a linear expansion less than or equal to 10%.

[0009] In some embodiments, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic forming a coating on and / or within the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The quaternary ammonium groups are directly adjacent to a surface of the porous support membrane.

[0010] In some embodiments, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coating at least a portion of the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. Greater than or equal to 50% of the pore volume of the porous support membrane is filled with the silica-based ceramic.

[0011] In some embodiments, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic forming a coating on and / or within the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The anion exchange capacity of the anion exchange membrane is greater than or equal to 0.01 meq / g.

[0012] In some embodiments, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coating at least a portion of the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The quaternary ammonium groups are present in the anion exchange membrane in an amount greater than or equal to 0.01 mmol per gram of the anion exchange membrane.

[0013] In some embodiments, an anion exchange material is provided. The anion exchange material comprises a silica-based ceramic comprising quaternary ammonium groups covalently bonded to the silica-based ceramic. The silica-based ceramic comprises Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The anion exchange capacity of the anion exchange material is greater than or equal to 0.01 meq / g. The average pore size of the silica-based ceramic is less than 10 nm.

[0014] In some embodiments, an anion exchange membrane is provided. In some embodiments, the anion exchange membrane comprises a silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The anion exchange capacity of the anion exchange membrane is greater than or equal to 0.01 meq / g.

[0015] In some embodiments, the anion exchange membrane comprises a silica-based ceramic. The anion exchange membrane has an anion exchange capacity greater than or equal to 0.01 meq / g and a linear expansion less than or equal to 10%.

[0016] In some embodiments, an anion exchange membrane is provided. The anion exchange membrane comprises a silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The anion exchange membrane has an anion permselectivity greater than or equal to 65%.

[0017] In some embodiments, an anion exchange membrane is provided. The anion exchange membrane comprises a silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The anion exchange membrane has a chloride ion conductivity greater than or equal to 0.00001 S / cm.

[0018] In some embodiments, an anion exchange membrane has a silica-based ceramic and a chloride ion conductivity greater than or equal to 0.00001 S / cm and a linear expansion less than or equal to 10%.

[0019] In some embodiments, an anion exchange membrane is provided. The anion exchange membrane comprises a silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The anion exchange membrane has an osmotic water permeance less than or equal to 100 mL / (hr·bar·m 2 ).

[0020] In some embodiments, an anion exchange membrane comprises a silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The silica-based ceramic includes pores, wherein the average diameter of the pores of the silica-based ceramic is greater than or equal to 1.1 times as large when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state.

[0021] In some embodiments, an anion exchange membrane comprises a silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The pores of the silica-based ceramic conform to a model of a small angle scattering spectrum in which the intensity (I) is a function of the scattering vector q when the anion exchange membrane is in a dry state, as follows:

[0022]

[0023] where a, cl, and c2 are adjustable parameters and bck is the background scattering; and the pores of the silica-based ceramic conform to a core-shell model of a small angle scattering spectrum in which the intensity (I) is a function of the scattering vector q when the anion exchange membrane is in a hydrated state, as follows:

[0024] I(q) = P(q)S(q) + bck,

[0025]

[0026]

[0027] where R o is the radius of the structural unit (pore), p 溶剂 is the scattering length density of the silica-based ceramic, D f is the fractal dimension, X is the correlation length, G is the standard mathematical gamma function, f is the volume fraction of the structural units of the silica-based ceramic being measured, V c is the volume of the core, V s is the volume of the shell, p c is the scattering length density of the core, p s is the scattering length density of the shell, p 单元 is the scattering length density of the pore, r c is the radius of the core, r s is the radius of the shell, and bck is the background scattering.

[0028] In some embodiments, methods of forming an anion exchange membrane are described. In some embodiments, the methods include exposing a porous support membrane having at least a portion coated with a silica-based ceramic to an amine. The silica-based ceramic includes a moiety containing a leaving group covalently bonded to the silica-based ceramic. The silica-based ceramic includes Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The methods include reacting the amine with the moiety to release the leaving group and form a quaternary ammonium group covalently bonded to the silica-based ceramic.

[0029] In some embodiments, methods of forming an anion exchange material are described. In some embodiments, the methods include exposing a resin including a silica-based ceramic to an amine. The silica-based ceramic includes a moiety containing a leaving group covalently bonded to the silica-based ceramic. The silica-based ceramic includes Si in an amount greater than or equal to 6 wt% of the silica-based ceramic. The methods include reacting the amine with the moiety to release the leaving group and form a quaternary ammonium group covalently bonded to the silica-based ceramic.

[0030] In some embodiments, methods for using the anion exchange membranes described herein in electrochemical applications are provided. The methods include contacting an anion exchange membrane with an electrolyte. The methods include passing an electrical current through an electrode in electrical communication with the electrolyte.

[0031] In some embodiments, methods for using the anion exchange materials described herein in electrochemical applications are provided. The methods include contacting the anion exchange material with an electrolyte. The methods include passing an electric current through an electrode in electrical communication with the electrolyte.

[0032] In some embodiments, methods for using the anion exchange membranes described herein as adsorption materials are provided. In some embodiments, the methods include flowing a fluid through the anion exchange membrane. The methods include adsorbing a component of the fluid.

[0033] In some embodiments, methods for using the anion exchange materials described herein as adsorption materials are provided. The methods include flowing a fluid through the anion exchange material. The methods include adsorbing a component of the fluid.

[0034] In some embodiments, methods for using the anion exchange membranes described herein in separation applications are provided. The methods include applying a transmembrane pressure to the anion exchange membrane.

[0035] Other advantages and novel features of the present application will become apparent from the following detailed description of the application when considered in conjunction with the accompanying drawings. In cases where the present specification and the documents incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. BRIEF DESCRIPTION OF DRAWINGS

[0036] Non-limiting embodiments of the present application will be described by way of example with reference to the accompanying drawings, which are schematic and not intended as precise representations of the application. In the drawings, each identical or nearly identical component that is illustrated in various figures is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every drawing where it appears. In the drawings:

[0037] Figure 1A is a schematic cross-sectional view of an exemplary anion exchange membrane comprising a silica-based ceramic according to some embodiments;

[0038] Figure 1B is a schematic cross-sectional view of an exemplary anion exchange membrane comprising a silica-based ceramic according to some embodiments, and an inset showing a magnified view of a pore of the silica-based ceramic;

[0039] Figure 2A is a schematic top-down view of an exemplary anion exchange membrane comprising a silica-based ceramic and a porous support membrane according to some embodiments.

[0040] Figure 2Bis a schematic cross-sectional view of an exemplary silica-based ceramic coating on a portion of a porous support membrane component according to some embodiments;

[0041] Figure 3 is a schematic view of quaternary ammonium groups covalently bonded to a silica-based ceramic according to some embodiments;

[0042] Figure 4A is a schematic cross-sectional view of an exemplary silica-based ceramic coating on a portion of a porous support membrane component according to some embodiments, wherein the coating comprises quaternary ammonium groups substantially uniformly distributed within the silica-based ceramic across the thickness of the coating;

[0043] Figure 4B is a schematic cross-sectional view of an exemplary silica-based ceramic coating on a portion of a porous support membrane component according to some embodiments, wherein the coating comprises quaternary ammonium groups substantially non-uniformly distributed within the silica-based ceramic across the thickness of the coating;

[0044] Figure 5 is a schematic top-down view of an exemplary anion exchange membrane comprising a silica-based ceramic and a compressible edge seal material according to some embodiments;

[0045] Figure 6 is a flow chart showing steps of an exemplary process for manufacturing a ceramic anion exchange membrane according to some embodiments;

[0046] Figure 7 is a schematic cross-sectional view of an anion exchange material comprising a silica-based ceramic according to some embodiments, wherein the anion exchange material comprises quaternary ammonium groups covalently bonded to the silica-based ceramic;

[0047] Figures 8A to 8D shows anion selectivity, osmotic water permeance, chloride conductivity, and small angle X-ray scattering data and fitting results for exemplary anion exchange membranes according to some embodiments;

[0048] Figure 9A shows small angle X-ray scattering data and fitting results for exemplary anion exchange membranes according to certain embodiments;

[0049] Figures 9B to 9D shows pore radius, bulk porosity, and anion exchange capacity data for exemplary anion exchange membranes as a function of TEOS:TMAPS molar ratio according to some embodiments;

[0050] Figures 10A to 10B shows selectivity and chloride conductivity data for exemplary anion exchange membranes at different porous support membrane thicknesses according to some embodiments;

[0051] Figures 11A to 11B Selectivity and chloride conductivity data for example anion exchange membranes according to some embodiments are shown as a function of number of coating layers, time of exposure to a silicon-containing precursor sol, and drying conditions; and

[0052] Figure 11C Cross-sectional SEM images of example anion exchange membranes according to some embodiments are shown. DETAILED DESCRIPTION

[0053] Anion exchange membranes and anion exchange materials comprising silica-based ceramics, and related methods, are provided. In some aspects, an anion exchange membrane is described that comprises a silica-based ceramic forming a coating on and / or within a porous support membrane. The anion exchange membranes and anion exchange materials can have certain structural or chemical attributes (e.g., pore size / distribution, chemical functionalization) that, alone or in combination, can result in advantageous performance characteristics in any of a variety of applications where it is desirable to selectively transport negatively charged ions through the membrane / material. For example, the anion exchange membranes or anion exchange materials described herein can exhibit relatively high anion exchange capacity, anion selectivity, and / or mechanical rupture strength, while in some cases also experiencing relatively low dimensional swelling (e.g., when in contact with water). In some embodiments, the silica-based ceramic comprises relatively small pores (e.g., substantially spherical nanometer-sized pores) that can contribute to some of these advantageous characteristics.

[0054] In some embodiments, the anion exchange membranes or anion exchange materials comprise quaternary ammonium groups covalently bonded to the silica-based ceramic. In some such cases, the quaternary ammonium groups are present at relatively high loadings as compared to certain existing anion exchange materials. In some embodiments, the quaternary ammonium groups are distributed substantially uniformly within the silica-based ceramic across the thickness of the coating formed by the silica-based ceramic, which in some cases can result in benefits over certain existing membranes that can only be functionalized at or near the surface.

[0055] In some embodiments, the anion exchange membranes and anion exchange materials described herein can be produced via sol-gel techniques, for example via the co-condensation of certain silanes on a porous support membrane. The anion exchange membranes and anion exchange materials can be used in a variety of applications, for example electrochemical (e.g., redox flow battery) processes and purification (e.g., desalination, gas / liquid separation) processes.

[0056] Certain existing commercially available anion exchange membranes are made from hydrocarbon- or perfluorocarbon-based polymers containing covalently bonded quaternary ammonium moieties. As a result, these anion exchange membranes have a nanostructure characterized by a mixture of interconnected worm-like hydrophilic domains in a hydrophobic matrix. In the presence of water (e.g., when using certain existing anion exchange membranes), these hydrophilic domains tend to swell (e.g., undergo dimensional swelling, such as linear swelling). Swelling of anion exchange membranes can be problematic in certain applications, as swelling can cause tension that can lead to membrane tearing and device failure. While certain techniques such as chemical crosslinking and / or mechanical reinforcement of the membrane can sometimes reduce swelling, there is a need for improved compositions and structures that can more effectively reduce swelling while maintaining or even enhancing the performance of anion exchange membranes and anion exchange materials.

[0057] It has been observed that anion exchange membranes containing rigid structures (e.g., ceramics) can experience less swelling than hydrocarbon- or perfluorocarbon-based membranes. However, certain existing ceramics are considered too brittle to be used in a standalone ceramic-based membrane. Thus, previous attempts to incorporate ceramics into anion exchange membranes have generally involved incorporating ceramic nanoparticles into, for example, a polymeric matrix. In the context of the present disclosure, it has been unexpectedly discovered that anion exchange membranes and anion exchange materials containing silica-based ceramics can be achieved without resorting to the use of nanoparticles incorporated into a polymeric matrix. For example, it has been discovered that anion exchange membranes containing silica-based ceramics containing functional groups covalently bonded to the silica-based ceramic, such as quaternary ammonium groups, can be achieved. In some embodiments, such functionalized silica-based ceramic compositions can have an ordered nanoporous structure. In some embodiments, the resulting anion exchange membranes exhibit unexpectedly beneficial performance characteristics (e.g., relatively high anion exchange capacity, relatively high chloride ion conductivity, relatively high permselectivity, high mechanical rupture strength) while exhibiting relatively low dimensional swelling. Such anion exchange membranes and anion exchange materials, as well as methods for making and using the same, are described herein.

[0058] In an aspect, an anion exchange membrane is generally described. Figure 1A is a schematic cross-sectional view of an exemplary anion exchange membrane 100. In some embodiments, an anion exchange membrane can achieve any of the various advantageous characteristics and performance characteristics reported in the present disclosure. For example, anion exchange membrane 100 can exhibit a relatively high anion exchange capacity, a relatively high anion permselectivity, a relatively high chloride ion conductivity, a relatively low osmotic water permeance, and / or a relatively low dimensional swelling (e.g., a relatively low linear swelling), details of which are provided in greater detail below. As noted above, an anion exchange membrane can be suitable for use in any of the various applications described in greater detail below.

[0059] Referring again to Figure 1A , the example anion exchange membrane 100 includes a silica-based ceramic 150. In some embodiments, the silica-based ceramic is a ceramic that includes or is formed from a silica (Si02) network, although the silica-based ceramic can include groups (e.g., terminal portions) not encompassed by the formula Si02. In some embodiments, the silica-based ceramic is porous (e.g., nanoporous). Figure 1B is a schematic cross-sectional view of an example anion exchange membrane 100 including an example silica-based ceramic 150 that is porous (e.g., nanoporous) according to some embodiments. Figure 1B An inset is shown depicting a magnified view of the silica-based ceramic 150, which illustrates an example pore including an example pore 152. The porosity (e.g., nanoporosity) of the silica-based ceramic can at least partially contribute to performance characteristics of the anion exchange membrane. The silica-based ceramic is described in more detail below. It should be understood that the figures shown herein are for illustrative purposes and can not necessarily be drawn to scale.

[0060] In some embodiments, the anion exchange membrane includes a porous support membrane. For example, in some embodiments, the anion exchange membrane 100 includes a porous support membrane. The porous support membrane can provide mechanical support for the entire anion exchange membrane. Figure 2A A schematic top-down view of an example anion exchange membrane 100 including a silica-based ceramic 150 and a porous support membrane 130 occluded by the silica-based ceramic 150 according to some embodiments is shown. For illustrative purposes, Figure 2A The porous support membrane 130 is shown without the presence of the silica-based ceramic 150 to the left of the arrow, while the anion exchange membrane 100 to the right of the arrow includes the presence of the silica-based ceramic 150, which occludes the porous support membrane from view. It should be understood that Figure 2A is illustrative of non-limiting embodiments, and in some embodiments, the coating formed by the silica-based ceramic does not completely cover the porous support membrane. For example, in some such embodiments, a portion of the porous support membrane 130 can not be occluded by the silica-based ceramic 150.

[0061] In some embodiments, the anion exchange membrane includes a silica-based ceramic that coats at least a portion of the porous support membrane. Referring again to Figure 2AAnion exchange membrane 100 includes silica-based ceramic 150 coated on porous support membrane 130 (to the right of the arrow, obscured from view by anion exchange membrane 100). In some such embodiments, the silica-based ceramic forms a coating on and / or within the porous support membrane. For example, the porous support membrane can be impregnated or encapsulated in the silica-based ceramic. In some embodiments, the silica-based ceramic coats a portion, but not all, of the porous support membrane. In such embodiments, the porous support membrane can be substantially coated with the silica-based ceramic.

[0062] Figure 2B A schematic cross-sectional view showing an exemplary coating 140 formed from silica-based ceramic 150, according to some embodiments, is shown. As exemplarily shown in this figure, coating 140 of silica-based ceramic 150 is on a surface of porous support membrane component 135 (e.g., a single fiber on or within the porous support membrane), according to some embodiments, a cross-section of which is shown in Figure 2B This exemplary embodiment (e.g., a coated fiber) can be a portion of an anion exchange membrane in which the silica-based ceramic completely coats the porous support membrane or partially coats the porous support membrane.

[0063] It should be understood that when a portion (e.g., layer, coating) is "on," "adjacent" to, in "contact" with, or "supported by" another portion, it can be directly on the portion, or an intervening portion (e.g., layer, coating) can also be present. A portion is "directly on," "directly adjacent," in "contact" with, or "directly supported by" another portion means that no intervening portion is present. It should also be understood that when a portion is referred to as being "on," "adjacent," in "contact" with, or "supported by" another portion, it can cover the entire portion or a portion of the portion.

[0064] In some embodiments, a coating of silica-based ceramic (e.g., coating 140) is present on a surface of the porous support membrane (e.g., directly on it). In some embodiments, the coating is present on a surface of the porous support membrane, while the interior of the porous support membrane is substantially uncoated. In other embodiments, however, a coating of silica-based ceramic is present within at least a portion of the interior of the porous support membrane (i.e., through the thickness of the porous support membrane). As one example, a coating of silica-based ceramic is formed on components within the interior of the porous support membrane that are accessible via, e.g., pores or voids. In some such cases, the coating fills at least a portion or all of the pores of the porous support membrane. In some embodiments, at least a portion of the interior of the porous support membrane is coated, while the surface of the porous support membrane is substantially uncoated.

[0065] As described in more detail below, the porous support membrane can include support components, e.g., fibers that provide structural support to the membrane. In some embodiments, substantially all of the support components of the porous support membrane are coated with silica-based ceramic. As one example, in some embodiments, the porous support membrane includes a nonwoven fabric of fibers. In some such cases, substantially all of the fibers (including fibers within the interior of the porous support membrane) are coated with silica-based ceramic. In other embodiments, however, not all of the support components of the porous support membrane are coated with silica-based ceramic. For example, in some embodiments in which the porous support membrane includes fibers as support components, not all of the fibers are coated with silica-based ceramic. The degree of coating can vary. In some cases, the coating of silica-based ceramic covers the entire porous support membrane (e.g., as shown in the anion exchange membrane 100 on the right side of the arrow), but in other cases, the coating of silica-based ceramic covers only a portion of the porous support membrane (e.g., only a subset of regions of the porous support membrane are coated, or only a portion of the support components are coated). Figure 2A In some embodiments in which a coating of silica-based ceramic is formed on and / or within the porous support membrane, the silica-based ceramic substantially fills all of the pores of the porous support membrane. For example, again referring to the anion exchange membrane 100 on the right side of the arrow, the silica-based ceramic coating 140 substantially fills all of the pores of the porous support membrane 110. In other embodiments, however, the silica-based ceramic coating does not substantially fill all of the pores of the porous support membrane. For example, in some embodiments, the silica-based ceramic coating does not substantially fill all of the pores of the porous support membrane, but rather, the coating is present on and / or within a subset of the pores of the porous support membrane. In some such cases, the coating of silica-based ceramic is present on and / or within a subset of the pores of the porous support membrane, while the remaining pores of the porous support membrane are substantially uncoated. In other cases, the coating of silica-based ceramic is present on and / or within a subset of the pores of the porous support membrane, while the remaining pores of the porous support membrane are coated with a different material (e.g., a different coating of silica-based ceramic, or a coating of a different material).

[0066] In some embodiments in which a coating of silica-based ceramic is formed on and / or within the porous support membrane, the silica-based ceramic substantially fills all of the pores of the porous support membrane. For example, again referring to the anion exchange membrane 100 on the right side of the arrow, the silica-based ceramic coating 140 substantially fills all of the pores of the porous support membrane 110. In other embodiments, however, the silica-based ceramic coating does not substantially fill all of the pores of the porous support membrane. For example, in some embodiments, the silica-based ceramic coating does not substantially fill all of the pores of the porous support membrane, but rather, the coating is present on and / or within a subset of the pores of the porous support membrane. In some such cases, the coating of silica-based ceramic is present on and / or within a subset of the pores of the porous support membrane, while the remaining pores of the porous support membrane are substantially uncoated. In other cases, the coating of silica-based ceramic is present on and / or within a subset of the pores of the porous support membrane, while the remaining pores of the porous support membrane are coated with a different material (e.g., a different coating of silica-based ceramic, or a coating of a different material). Figure 2AIn some embodiments, when the porous support membrane 130 is coated with the silica-based ceramic, all of the pores of the porous support membrane 130, including the pores 132, are completely filled with the silica-based ceramic. In such embodiments, the resulting overall anion exchange membrane porosity will correspond to the porosity of the silica-based ceramic material. In other embodiments, where the silica-based ceramic forms a coating on and / or within the porous support membrane, the silica-based ceramic does not completely fill the pores of the porous support membrane, but reduces the pore size (e.g., average pore diameter) of the porous support membrane. In such embodiments, the overall porosity of the resulting overall anion exchange membrane will be different than the porosity of the silica-based ceramic material itself. In this case, the resulting overall exchange membrane will have a different porosity than the porosity of the silica-based ceramic coating because there will be both the reduced size pores of the porous support membrane and pores corresponding to the silica-based ceramic. In such embodiments, the silica-based ceramic coating can have a porosity in one or more of the ranges described herein, and the overall anion exchange membrane can have a porosity in one or more of the ranges described herein.

[0067] In some, but not necessarily all, embodiments, the anion exchange membrane includes one or more additional layers or coatings on (e.g., on top of) the coating comprising the silica-based ceramic. However, in some embodiments, there are no other layers or coatings on the coating comprising the silica-based ceramic (e.g., the silica-based coating forms the outermost surface of the anion exchange membrane). In some embodiments, the silica-based ceramic forms a single layer on the porous support membrane.

[0068] Forming the coating of silica-based ceramic on and / or within at least a portion of the porous support membrane can be accomplished using any of a variety of suitable techniques. In some embodiments, the coating of silica-based ceramic (e.g., coating 140) is formed using sol-gel techniques. For example, with reference back to FIG. 1, the coating 140 of silica-based ceramic can be formed by applying a sol-gel solution to the porous support membrane 130 and then drying and curing the sol-gel solution to form the coating 140 of silica-based ceramic on the porous support membrane 130. Figure 2AIn some embodiments, porous support membrane 130 (shown to the left of the arrow) is coated using a sol-gel technique, resulting in anion exchange membrane 100 comprising a silica-based ceramic 150 coated on and / or within at least a portion of porous support membrane 130 (shown to the right of the arrow). In some cases, sol-gel techniques such as those described herein can provide for relatively fast and inexpensive formation of anion exchange membranes comprising silica-based ceramics. In some such cases, relatively mild conditions can be used to form the silica-based ceramic coating using sol-gel techniques, and the resulting silica-based ceramic can have certain structural properties (e.g., ordered nanopores) that can provide advantageous performance in certain cases. Exemplary sol-gel techniques are described in more detail below.

[0069] In some embodiments, the silica-based ceramic comprises one or more functional groups covalently bonded to the silica-based ceramic. The presence of functional groups covalently bonded to the silica-based ceramic can contribute at least in part to the performance of the anion exchange membrane. For example, in some embodiments, the silica-based ceramic comprises functional groups capable of binding and dissociating cations. In some embodiments, the functional groups covalently bonded to the silica-based ceramic are positively charged functional groups. For example, in some embodiments, the functional groups covalently bonded to the silica-based ceramic are quaternary ammonium groups. In some embodiments, the functional groups covalently bonded to the silica-based ceramic are imidazolium groups. In some embodiments, the functional groups covalently bonded to the silica-based ceramic are weakly basic groups, such as amine groups (e.g., tertiary amine groups). The functional groups can be bonded to Si in the silica-based ceramic via a linking group (e.g., an organic linking group). For example, the nitrogen of a quaternary ammonium group can be covalently bonded to Si in the silica-based ceramic via an organic linking group, such as a linking group selected from the group consisting of optionally substituted C 1-18 alkylene and arylene groups (or C 1-8 alkylene and arylene groups, or C 1-4 alkylene and arylene groups) covalently bonded to Si in the silica-based ceramic. It should be understood that in the present disclosure, any description of a certain item “selected from” a list of items can be replaced with a description of the certain item selected from “a group consisting of” the items. For example, in some embodiments, the nitrogen of a quaternary ammonium group can be covalently bonded to Si in the silica-based ceramic via an organic linking group, such as a linking group selected from the group consisting of optionally substituted C 1-18 alkylene and arylene groups covalently bonded to Si in the silica-based ceramic.

[0070] The functional group can be capable of binding and dissociating cations, such as protons or certain metal ions. As an example, a quaternary ammonium group bonded to a silica-based ceramic can be capable of binding and dissociating anions, such as hydroxide or halide. Exemplary anions that can be capable of binding and dissociating with a functional group (e.g., a quaternary ammonium group) include F - , CI - , Br - , I - , OH - , SO3 - , CO3 - , PO4 3- , BO3 - , NO3 - , NO2 - , and CI O3 - .

[0071] Figure 3 is a schematic of a quaternary ammonium group covalently bonded to a silica-based ceramic 150, according to some embodiments. As schematically shown in this figure, the quaternary ammonium group is covalently connected to an interior portion of the silica-based ceramic material. In some embodiments, the functional group (e.g., quaternary ammonium group) is exposed at an outer surface of the silica-based ceramic (e.g., exterior of a coating of the silica-based ceramic). In some cases, the functional group (e.g., quaternary ammonium group) covalently bonded to the silica-based ceramic group is exposed at a surface of a pore in the silica-based ceramic. For example, in Figure 3 , the quaternary ammonium group covalently bonded to the silica-based ceramic 150 is shown exposed at a surface of a pore 152 of the silica-based ceramic. In some embodiments, having a functional group such as a quaternary ammonium group present at a surface of a pore of a silica-based ceramic can allow for relatively efficient transport of anions through the anion exchange membrane, and / or a relatively high anion exchange capacity of the anion exchange membrane.

[0072] One of ordinary skill in the art will appreciate that, at any given time, the relative amount of the conjugate acid of the functional group covalently bonded to the silica-based ceramic compared to the amount of the conjugate base of the functional group present will depend on the conditions and environment of the anion exchange membrane or anion exchange material. For example, in embodiments in which the functional group is an imidazole or an amine (e.g., a tertiary amine), the relative amounts of imidazolium salt to imidazole or ammonium to amine group will depend, at least in part, on the pH of any solution in contact with the membrane or material, the pK a of other functional groups, if present, and / or the concentration of anions in any solution in contact with the membrane or material.

[0073] In some embodiments, the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic across the thickness of the coating. The thickness of the coating refers to the thickness in a direction from a surface of a component of the porous support membrane (e.g., a surface of an individual fiber of the porous support membrane) coated by the coating to the nearest exposed surface of the silica-based ceramic coating. The exposed surface of the silica-based ceramic coating refers to any surface of the silica-based ceramic in communication with the exterior of the anion exchange membrane, another layer or region of material, or an un-filled pore or void of the porous support membrane. For example, in one embodiment, the exposed surface can be exposed to air or an additional environment different than the silica-based ceramic coating itself. Figure 4A is a schematic cross-sectional view of an exemplary coating 140 of silica-based ceramic 150 on a portion of a component 135 of a porous support membrane (e.g., a fiber on or within the porous support membrane) according to some embodiments. In some embodiments, Figure 4A The coating 140 in has quaternary ammonium groups substantially uniformly distributed within the silica-based ceramic 150 across the thickness 160 of the coating 140. Having functional groups such as quaternary ammonium groups substantially uniformly distributed within the silica-based ceramic across the thickness of the coating can result in a number of advantages in some cases. One advantage can be that a substantially uniform distribution of functional groups in the silica-based ceramic can enable a relatively high loading of functional groups for a given amount of silica-based ceramic, which can result in a high anion exchange capacity per unit mass, and beneficial performance characteristics. Another possible advantage is that a substantially uniform distribution of functional groups in the silica-based ceramic can result in a relatively small distance between functional groups within the membrane, which is in contrast to certain existing membranes in which functional groups (e.g., quaternary ammonium groups) are relatively concentrated (e.g., near the surface), which can result in regions of the membrane having a relatively small amount of functional groups and can limit anion conductivity. The substantially uniform distribution of functional groups (e.g., quaternary ammonium groups) can be achieved, for example, using certain sol-gel techniques, as described in more detail below.

[0074] Figure 4B is a schematic cross-sectional view of an exemplary coating 240 comprising silica-based ceramic 250 on a portion of a component 135 of a porous support membrane (e.g., a fiber on or within the porous support membrane) according to some embodiments. In Figure 4B In, the coating 240 comprises quaternary ammonium groups substantially non-uniformly distributed within the silica-based ceramic 250 across the thickness 260 of the coating 240. More specifically, in Figure 4B In, the quaternary ammonium groups are concentrated at or near the surface of the coating 240, leaving regions 245 of the coating free of quaternary ammonium groups.

[0075] Such a distribution of substantially non-uniformly distributed quaternary ammonium groups can result from the use of surface functionalized coating techniques rather than certain sol-gel techniques described herein. For example, a coating comprising a silica-based ceramic containing substantially non-uniformly distributed quaternary ammonium groups can result from a manufacturing technique in which a support (e.g., a porous support membrane) is first coated with a material that does not contain quaternary ammonium groups (or a relatively small amount of quaternary ammonium groups) (e.g., with a ceramic such as a silica-based ceramic). Then, after the first coating step, a second coating step is performed in which a material that will contain quaternary ammonium groups (or contain a relatively greater amount of quaternary ammonium groups) is coated over the first coating layer. Silica-based ceramic coatings having a substantially non-uniform distribution of quaternary ammonium groups can result in relatively poor performance of the resulting anion exchange membrane. For example, in some embodiments, an anion exchange membrane can have a relatively lower quaternary ammonium group loading compared to an anion exchange membrane having a coating with a substantially uniform distribution of quaternary ammonium groups. Further, in some cases, such a coating that does not have a substantially uniform distribution of quaternary ammonium groups and thus has regions (e.g., regions 245) containing a relatively low abundance of quaternary ammonium groups can have a relatively lower anion conductivity due to such regions.

[0076] In some embodiments in which the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic across the thickness of the coating, the amount of quaternary ammonium groups at any given point within the cross-section of the thickness of the coating varies by no more than 50% compared to the average amount of quaternary ammonium groups in the silica-based ceramic. For example, again with reference to FIG. 2, in some embodiments, the amount of quaternary ammonium groups at any given point within the cross-section of the thickness of the coating varies by no more than 50% compared to the average amount of quaternary ammonium groups in the silica-based ceramic. Figure 4AThe amount of quaternary ammonium groups at any point A, or any point B, of the cross-section 143 of the coating 140 varies by no more than 50% from the average amount of quaternary ammonium groups in the coating 140. In some embodiments where the quaternary ammonium groups are substantially uniformly distributed across the thickness of the coating within the silica-based ceramic, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that at any given point within the thickness cross-section of the coating is within greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 90%, greater than or equal to 95%, or greater than or equal to 99% of the average amount of quaternary ammonium groups in the coating. In some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that at any given point within the thickness cross-section of the coating is within less than or equal to 100%, less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 75%, less than or equal to 70%, less than or equal to 60%, or less of the average amount of quaternary ammonium groups in the coating. Combinations of these ranges are possible. For example, in some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that at any given point within the thickness cross-section of the coating is within greater than or equal to 50% and less than or equal to 100% of the total average amount of quaternary ammonium groups in the coating. As an illustrative calculation, if the average amount of quaternary ammonium groups of the silica-based ceramic is determined to be 5 weight percent (wt%) (as determined by scanning electron microscopy / energy dispersive X-ray technology (SEM / EDX)), and it is determined that the amount of quaternary ammonium groups at all points (e.g., points A) within at least 5 cross-sections across the thickness of the silica-based ceramic is greater than or equal to 2.5 wt% and less than or equal to 7.5 wt%, then the silica-based ceramic would be considered to have quaternary ammonium groups substantially uniformly distributed across the thickness of the coating based on the average amount of quaternary ammonium groups measured. Figure 4A

[0077] In contrast, in some cases where the quaternary ammonium groups are not substantially uniformly distributed across the thickness of the coating within the silica-based ceramic, the amount of quaternary ammonium groups is within less than 50% of the average amount of quaternary ammonium groups in the coating (in other words, the amount of quaternary ammonium groups at any given point within the thickness cross-section of the coating varies by more than 50% from the average total amount of quaternary ammonium groups in the silica-based ceramic). For example, again referring to Figure 4B The amount of quaternary ammonium groups at any point C, or any point D, of the cross-section 243 of the coating 240 varies by more than 50% from the average amount of quaternary ammonium groups in the coating 240. As an illustrative calculation, if the average amount of quaternary ammonium groups of the silica-based ceramic is determined to be 5 wt%, and it is determined that the amount of quaternary ammonium groups at any point (e.g., points C) within the cross-section across the thickness of the silica-based ceramic is greater than or equal to 2.5 wt% and less than or equal to 7.5 wt%, then the silica-based ceramic would be considered to have quaternary ammonium groups substantially uniformly distributed across the thickness of the coating based on the average amount of quaternary ammonium groups measured. Figure 4B ​If the amount of quaternary ammonium groups at point D is less than 2.5% by weight or greater than 7.5% by weight, then the silica-based ceramic will not be considered to have a substantially uniform distribution of quaternary ammonium groups across the coating thickness based on the measured average amount of quaternary ammonium groups.

[0078] In some embodiments where the quaternary ammonium groups are substantially uniformly distributed across the coating thickness within the silica-based ceramic, the amount of quaternary ammonium groups at any given point within the coating thickness cross-section changes by no more than 75% compared to the maximum amount of quaternary ammonium groups in the silica-based ceramic. For example, see again... Figure 4A The amount of quaternary ammonium groups at any point A or any point B of the cross section 143 of the coating 140 changes by no more than 75% compared to the maximum amount of quaternary ammonium groups in the coating 140. In some embodiments in which the quaternary ammonium groups are substantially uniformly distributed across the coating thickness within the silica-based ceramic, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that at any given point within the thickness cross section, the maximum amount of quaternary ammonium groups in the coating is greater than or equal to 25%, greater than or equal to 40%, greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 90%, greater than or equal to 95%, or greater than or equal to 99%. In some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that at any given point within the thickness section of the coating, the maximum amount of quaternary ammonium groups in the coating is less than or equal to 100%, less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 75%, less than or equal to 70%, less than or equal to 60%, or less. Combinations of these ranges are possible. For example, in some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that at any given point within the thickness section of the coating, the maximum total amount of quaternary ammonium groups in the coating is greater than or equal to 25% and less than or equal to 100%. As an exemplary calculation, if the maximum amount of quaternary ammonium groups in the silica-based ceramic is determined to be 10% by weight (e.g., determined by scanning electron microscopy / energy dispersive X-ray technique (SEM / EDX)), and all points within at least five sections across the thickness of the silica-based ceramic are determined (e.g., ... Figure 4A If the amount of quaternary ammonium groups at point A) is greater than or equal to 2.5% by weight, then the silica-based ceramic is considered to have a substantially uniform distribution of quaternary ammonium groups across the coating thickness based on the maximum amount of quaternary ammonium groups measured. It should be understood that in the above calculations, the relative amount of quaternary ammonium groups is important, and the unit used to express the amount measured by SEM / EDX technology is not particularly important. Although weight percentages are used in the exemplary calculations above, other units used to express the amount of quaternary ammonium groups can be readily obtained from SEM / EDX technology or can also be derived from weight percentages.

[0079] In contrast, in some cases where the quaternary ammonium groups are not substantially uniformly distributed across the thickness of the coating within the silica-based ceramic, the amount of quaternary ammonium groups at a point is less than 25% of the maximum amount of quaternary ammonium groups within the coating (in other words, the amount of quaternary ammonium groups at any given point within the thickness cross-section of the coating varies by more than 75% compared to the maximum total amount of quaternary ammonium groups in the silica-based ceramic). For example, again referring to Figure 4B , the amount of quaternary ammonium groups at any point C, or any point D, of the cross-section 243 of the coating 240 varies by more than 75% compared to the maximum amount of quaternary ammonium groups in the coating 240. As an example calculation, if the maximum amount of quaternary ammonium groups of the silica-based ceramic is determined to be 10 wt%, and the amount of quaternary ammonium groups at any point (e.g., point D in Figure 4B ) within the thickness cross-section of the silica-based ceramic is determined to be less than 2.5 wt%, then the silica-based ceramic would not be considered to have quaternary ammonium groups substantially uniformly distributed across the thickness of the coating based on the measured maximum amount of quaternary ammonium groups.

[0080] The amount of quaternary ammonium groups within the coating and within any cross-section of the coating can be determined using a combination of scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. For example, the following process can be performed. The anion exchange membrane is dried and a cross-section sample is mounted on a SEM stub. The sample is first imaged using secondary electron and / or backscatter detection, then imaged via EDX. The EDX data can be acquired as a line profile across the sample cross-section or as a map of the entire sample. The EDX data can then be collated to determine the average or maximum amount of quaternary ammonium groups (e.g., in wt%) present in the coating, as well as the amount of quaternary ammonium groups at points along any cross-section using the line profile from the SEM / EDX data. Three or more line profiles can be acquired to determine a statistically representative data set.

[0081] In some embodiments, the quaternary ammonium groups are directly adjacent to the surface of the porous support membrane. For example, again referring to Figure 4A , according to some embodiments, the coating 140 comprising the silica-based ceramic 150 comprises quaternary ammonium groups, and the quaternary ammonium groups are directly adjacent to the porous support membrane component 135, such that they are directly adjacent to the porous support membrane to which the porous support membrane component 135 belongs. In some embodiments, there is no intervening layer between the silica-based ceramic comprising quaternary ammonium groups in the porous support membrane. For example, in some embodiments, there is no intervening layer between the silica-based ceramic 150 and the porous support membrane component 135 in Figure 4A .

[0082] In some embodiments, the quaternary ammonium groups are relatively close to the surface of the porous support membrane (e.g., the surface of the support component that makes up the porous support membrane). For example, in some embodiments, at least some of the quaternary ammonium groups are within 1 pm, within 500 nm, within 100 nm, within 50 nm, within 10 nm, within 5 nm, within 1 nm, or less, of the surface of the porous support membrane. In some embodiments, at least some of the quaternary ammonium groups are within 1 pm to 10 pm of the surface of the porous support membrane. In some embodiments, the quaternary ammonium groups are in contact (e.g., direct contact) with the surface of the porous support membrane. The distance between the porous support membrane and the quaternary ammonium groups can be determined, for example, using an analytical electron microscope equipped with a transmission electron microscope (TEM) and an X-ray spectrometer.

[0083] As noted above, in some embodiments, the anion exchange membrane or anion exchange material has a relatively high loading of functional groups. For example, in some embodiments, the anion exchange membrane or anion exchange material has a relatively high loading of quaternary ammonium groups. Having a relatively high loading of functional groups, such as quaternary ammonium groups, can at least partially result in beneficial performance characteristics of the anion exchange membrane or anion exchange material. For example, a high loading of quaternary ammonium groups can contribute to a relatively high anion exchange capacity, anion permselectivity, and / or anion conductivity (e.g., chloride conductivity, hydroxide conductivity). Certain methods described herein, such as certain sol-gel techniques involving the co-condensation of functionalized and non-functionalized silanes, can provide for a loading of quaternary ammonium groups that is difficult to achieve in different cases using certain prior art.

[0084] In some embodiments, the quaternary ammonium groups are present in the anion exchange membrane or anion exchange material in an amount greater than or equal to 0.01 mmol, greater than or equal to 0.05 mmol, greater than or equal to 0.1 mmol, greater than or equal to 0.3 mmol, greater than or equal to 0.5 mmol, greater than or equal to 0.7 mmol, greater than or equal to 1 mmol, greater than or equal to 2 mmol, greater than or equal to 3 mmol, or more per gram of the anion exchange membrane or anion exchange material. In some embodiments, the quaternary ammonium groups are present in the anion exchange membrane or anion exchange material in an amount less than or equal to 10 mmol, less than or equal to 5 mmol, or less per gram of the anion exchange membrane or anion exchange material. Combinations of these ranges are possible. For example, in some embodiments, the quaternary ammonium groups are present in the anion exchange membrane or anion exchange material in an amount greater than or equal to 0.01 mmol and less than or equal to 10 mmol, or greater than or equal to 0.1 mmol and less than or equal to 10 mmol per gram of the anion exchange membrane or anion exchange material. It should be understood that the loading described herein refers to the sum of quaternary ammonium cations (i.e., charged groups) and quaternary ammonium salts (i.e., neutral groups comprising quaternary ammonium groups bound to anions). For example, if an anion exchange membrane or anion exchange material comprises 0.1 mmol of free quaternary ammonium cations and 0.3 mmol of quaternary ammonium groups bound to anions per gram of the anion exchange membrane or anion exchange material, the quaternary ammonium groups will be present in the anion exchange membrane or anion exchange material in an amount of 0.4 mmol per gram of the anion exchange membrane or anion exchange material. The loading of quaternary ammonium groups within the anion exchange membrane or anion exchange material can be determined by performing the measurement of the anion exchange capacity of the anion exchange membrane as described below, and the number of chloride ions measured in solution (as determined by titration) is considered to be equal to the number of quaternary ammonium groups in the anion exchange membrane. The loading can then be determined using the number of quaternary ammonium groups (in mmol) and dividing by the weight of the dried anion exchange membrane (in g). It should be understood that the above amounts and measurements of loading of quaternary ammonium groups refer to accessible quaternary ammonium groups, and not to quaternary ammonium groups that are inaccessible to solvents and ions (e.g., quaternary ammonium groups that are trapped in closed pores, unable to be contacted by solvents or anions).

[0085] As noted above, a silica-based ceramic (e.g., silica-based ceramic 150) can be a ceramic that primarily comprises a network of silicon dioxide (Si02), but the silica-based ceramic can comprise groups (e.g., terminal portions) that are not described by the formula Si02. For example, in some embodiments, the silica-based ceramic comprises a network of silicon dioxide that contains terminal hydroxyl groups, terminal organic groups, and / or terminal functional groups (e.g., quaternary ammonium groups). In some embodiments, a relatively high percentage of Si atoms in the silica-based ceramic are in a tetrahedral environment and are bonded to oxygen, hydroxyl groups, or functional groups (e.g., quaternary ammonium groups). For example, in some embodiments, a relatively high percentage of silica-based ceramic can be described using the following structure (I):

[0086]

[0087] where each R group can independently be a hydroxyl group, -OSiR3, or a moiety comprising a functional group such as a quaternary ammonium group. For example, in some cases, R can be a trialkylammonium alkoxide group, such as N,N,N-trimethylammonium propane. As can be seen from this structure, the silica-based ceramic can comprise an extended (although not necessarily single-crystalline) ceramic structure comprising functional groups such as quaternary ammonium groups covalently bonded to the silica-based ceramic. For example, in some embodiments, the silica-based ceramic can comprise an extended ceramic structure that can be described using the following structure (II):

[0088]

[0089] where each R group can independently be a hydroxyl group, -OSiR3, or a moiety comprising a functional group such as a quaternary ammonium group.

[0090] In some embodiments, the silica-based ceramic can comprise a structure that can be described using the following structure (III):

[0091]

[0092] where each R group can independently be a hydroxyl group, -OSiR3, or a moiety comprising a functional group such as a quaternary ammonium group, and R' can independently be an optionally substituted alkyl, cyclic, or aryl group.

[0093] The silica-based ceramic of the anion exchange membrane can have one or more properties of ceramics known in the art. For example, the silica-based ceramic can be relatively brittle, have a relatively high density, have a relatively high hardness, and / or have a relatively high melting point. In some embodiments, the silica-based ceramic is polycrystalline. The silica-based ceramics described herein are contrasted with anion exchange membranes comprising silica (e.g., functionalized silica nanoparticles) particles (e.g., nanoparticles) suspended in a non-silica-based matrix (e.g., a polymeric matrix, such as a carbon-based polymeric matrix).

[0094] In some embodiments, silicon is present in the silica-based ceramic in a relatively high amount. Because the silica-based ceramic is primarily silica-based, rather than having a relatively high percentage of other components, such as a polymeric matrix, Si can be present in the silica-based ceramic in a relatively high amount. In some embodiments, in the silica-based ceramic, the silica-based ceramic comprises Si in an amount greater than or equal to 6 weight percent (wt%), greater than or equal to 10 wt%, greater than or equal to 12 wt%, greater than or equal to 15 wt%, greater than or equal to 17 wt%, greater than or equal to 20 wt%, greater than or equal to 24 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, or more. In some embodiments, in the silica-based ceramic, the silica-based ceramic comprises Si in an amount less than or equal to 60 wt%, less than or equal to 50 wt%, less than or equal to 47 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, less than or equal to 28 wt%, less than or equal to 26 wt%, less than or equal to 24 wt%, less than or equal to 22 wt%, less than or equal to 20 wt%, less than or equal to 17 wt%, or less. Combinations of these ranges are possible. For example, in some embodiments, in the silica-based ceramic, the silica-based ceramic comprises Si in an amount greater than or equal to 6 wt% and less than or equal to 60 wt%, or greater than or equal to 11 wt% and less than or equal to 26 wt%.

[0095] In some embodiments, in the silica-based ceramic, the silica-based ceramic comprises Si in an amount greater than or equal to 1.5 mole percent (mol%), greater than or equal to 3 mol%, greater than or equal to 5 mol%, greater than or equal to 8 mol%, greater than or equal to 10 mol%, greater than or equal to 12 mol%, greater than or equal to 15 mol%, greater than or equal to 18 mol%, greater than or equal to 20 mol%, or more. In some embodiments, in the silica-based ceramic, the silica-based ceramic comprises Si in an amount less than or equal to 33.4 mol%, to 30 mol%, less than or equal to 28 mol%, less than or equal to 26 mol%, less than or equal to 24 mol%, less than or equal to 22 mol%, less than or equal to 20 mol%, less than or equal to 18 mol%, or less. Combinations of these ranges are possible. For example, in some embodiments, in the silica-based ceramic, the silica-based ceramic comprises Si in an amount greater than or equal to 1.5 mol% and less than or equal to 33.4 mol%, greater than or equal to 8 mol% and less than or equal to 20 mol%, greater than or equal to 2.8 mol% and less than or equal to 18 mol%, or greater than or equal to 12 mol% and less than or equal to 18 mol%.

[0096] In some embodiments in which the silica-based ceramic comprises a nitrogen-containing functional group, such as a quaternary ammonium group, the molar ratio of Si to nitrogen in the silica-based ceramic depends on the loading of the nitrogen-containing functional group in the silica-based ceramic. In some embodiments, the silica-based ceramic has a silicon to nitrogen molar ratio greater than or equal to 1 : 1, greater than or equal to 1.5: 1, greater than or equal to 2: 1, greater than or equal to 3: 1, greater than or equal to 4: 1, greater than or equal to 5: 1, greater than or equal to 10: 1, greater than or equal to 25: 1, or greater. In some embodiments, the silica-based ceramic has a silicon to nitrogen molar ratio less than or equal to 120: 1, less than or equal to 75: 1, less than or equal to 50: 1, less than or equal to 25: 1, less than or equal to 10: 1, less than or equal to 4: 1, or less. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic has a silicon to nitrogen molar ratio greater than or equal to 1 : 1 and less than or equal to 120: 1, greater than or equal to 1 : 1 and less than or equal to 10: 1, or greater than or equal to 1 : 1 and less than or equal to 4: 1.

[0097] In some embodiments, the molar ratio of Si to carbon in the silica-based ceramic depends on the loading of carbon-containing groups, such as organic moieties (e.g., organofunctional groups), within the silica-based ceramic. In some embodiments, the silica-based ceramic has a silicon to carbon (Si:C) molar ratio greater than or equal to 1 : 100, greater than or equal to 1 : 75, greater than or equal to 1 : 50, greater than or equal to 1 : 40, greater than or equal to 1 : 25, greater than or equal to 1 : 16, greater than or equal to 1 : 10, greater than or equal to 1 : 5, or greater than or equal to 1 : 3, greater than or equal to 1 : 1, or greater. In some embodiments, the silica-based ceramic has a silicon to carbon molar ratio less than or equal to 3,000: 1, less than or equal to 2,000: 1, less than or equal to 1,000: 1, less than or equal to 500: 1, less than or equal to 200: 1, less than or equal to 100: 1, less than or equal to 75: 1, less than or equal to 50: 1, less than or equal to 25: 1, less than or equal to 10: 1, less than or equal to 2: 1, less than or equal to 1 : 1, or less. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic has a silicon to carbon molar ratio greater than or equal to 1 : 100 and less than or equal to 3,00: 1, greater than or equal to 1 : 100 and less than or equal to 100: 1, greater than or equal to 1 : 40 and less than or equal to 10: 1, or greater than or equal to 1 : 3 and less than or equal to 2: 1.

[0098] The weight percent and mole percent and molar ratios in the above-described silica-based ceramics can be determined by removing the silica-based ceramic from the remainder of the anion exchange membrane or anion exchange material (e.g., a porous support membrane, a compressible edge material, etc.) and performing elemental analysis, such as inductively coupled plasma mass spectrometry (ICP-MS) or nuclear magnetic resonance (NMR).

[0099] As described above, in some embodiments, sol-gel technology can be used to form silica-based ceramics. Therefore, in some cases, silica-based ceramics are derived from sol-gels. In some embodiments, the sol used in the sol-gel technology is a silica-containing precursor sol (i.e., the silica-based ceramic is derived from a silica-containing precursor sol). For example, during the manufacture of anion exchange membranes, one or more components of anion exchange membranes, such as the porous support membranes described herein, can be coated with a silica-containing precursor sol during at least one step of the manufacturing process. Silica-containing precursor sols can contain a variety of suitable silica-containing precursor components such as silica gel particles, siloxanes, silicates, silanols, silanes, alkoxysilanes, tetraalkyl orthosilicates, halosilanes, or combinations thereof. In some embodiments, silica-based ceramics are derived from silica-containing precursor sols containing two or more different silica-containing precursor components. In some such cases, silica-based ceramics are formed via the co-condensation of two or more silicon-containing precursor components (e.g., two or more different silanes or substituted silanes).

[0100] In some embodiments, the silica-based ceramics derived from the silica-containing precursor sol contain a silica-containing precursor that includes an ammonium group or a portion containing a leaving group (e.g., a halogen group). In some embodiments, the silica-based ceramics are derived from mixtures (e.g., silica-containing precursor sols) containing nitrogen-containing (e.g., ammonium) silanes (e.g., substituted alkoxysilanes). In some embodiments, the silica-based ceramics are derived from mixtures (e.g., silica-containing precursor sols) containing compounds having structure (IV).

[0101]

[0102] Where R 1 R 2 and R 3 Independently selected from the arbitrarily substituted C 1-18 Alkoxy and halogen, L is selected from the optionally substituted C 1-18 Alkylene and arylene groups, and X is a leaving group. In some embodiments, R 1 R 2 and R 3 Each of them is independently selected from the arbitrarily substituted C. 1-8 Alkoxy and halogen, L is selected from the optionally substituted C 1-8 Alkylene and arylene groups, and X is a leaving group. In some embodiments, R 1 R 2 and R 3 Each of them is independently selected from the arbitrarily substituted C. 1-4 Alkoxy and halogen, L is selected from the optionally substituted C1-4 The alkylene and arylene groups, and X, are leaving groups. In some embodiments, X is selected from chlorine, bromine, iodine, toluenesulfonyl, and trifluoromethanesulfonyl.

[0103] In some implementations, silica-based ceramics are derived from mixtures containing compounds having a structure (V) (e.g., silica-containing precursor sols):

[0104]

[0105] Among them, each A 1 It is independently selected from hydrogen, methyl, ethyl, propyl, or butyl, n is greater than or equal to 1 and less than or equal to 18, and X is a leaving group (e.g., a leaving group selected from chlorine, bromine, iodine, toluenesulfonyl, and trifluoromethanesulfonyl).

[0106] As an example, in some embodiments, silica-based ceramics are derived from mixtures containing (3-chloropropyl)triethoxysilane (3CPTES) (e.g., silica-containing precursor sols). In some cases, silica-based ceramics derived from the aforementioned compounds containing leaving groups can react with amines to form quaternary ammonium groups, as described in more detail below.

[0107] In some implementations, silica-based ceramics are derived from mixtures containing compounds having structure (VI) (e.g., silica-containing precursor sols):

[0108]

[0109] Where R 4 R 5 and R 6 Independently selected from the arbitrarily substituted C 1-18 Alkoxy and halogen, L is selected from the optionally substituted C 1-18 Alkylenes and arylenes, and R 7 R 8 and R 9 Independently selected from the arbitrarily substituted C 1-18 Alkyl, cycloyl, and aryl groups. In some embodiments, R 4 R 5 and R 6 Each of them is independently selected from the arbitrarily substituted C. 1-8 Alkoxy and halogen, L is selected from the optionally substituted C 1-8 Alkylenes and arylenes, and R 7 R 8 and R 9 Each of them is independently selected from the arbitrarily substituted C. 1-4 Alkyl, cycloyl, and aryl groups. In some embodiments, R 4, R 5 and each of R 6 is independently selected from the group consisting of optionally substituted C 1-4 alkoxy and halogen, L is selected from the group consisting of optionally substituted C 1-4 alkylene and arylene, and each of R 7 , R 8 and R 9 is independently selected from the group consisting of optionally substituted C 1-4 alkyl, cycloalkyl, and aryl.

[0110] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica- containing precursor sol) comprising a compound having structure (VII):

[0111]

[0112] wherein each A 2 is independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, or butyl, n is greater than or equal to 1 and less than or equal to 18, and each of R 10 , R 11 , and R 12 is independently selected from the group consisting of methyl, ethyl, propyl, butyl, cyclohexyl, and benzyl.

[0113] As one example, in some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising trimethoxysilylpropyl-N,N,N- trimethylammonium (TMAPS). As another example, in some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising triethoxysilylpropyl-N,N,N-trimethylammonium (TEAPS).

[0114] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica- containing precursor sol) comprising a compound having structure (VIII):

[0115]

[0116] wherein each R 13 is independently selected from the group consisting of hydrogen or optionally substituted C 1-18 alkyl. In some embodiments, each R 13 is independently selected from the group consisting of hydrogen or optionally substituted C 1-8 alkyl. In some embodiments, each R 13 is independently selected from the group consisting of hydrogen or optionally substituted C 1-4 alkyl. In some embodiments, each R 7 is independently selected from the group consisting of methyl, ethyl, propyl, and butyl.

[0117] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising tetraethyl orthosilicate (TEOS) and / or tetraethyl orthosiloxane. In some embodiments, the silica-based ceramic is derived from a single-phase mixture (e.g., a single-phase silica-containing precursor sol) comprising both a compound having structure (VIII) (e.g., TEOS) and a compound having structure (IV) (e.g., (3-chloropropyl)triethoxysilane). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising a compound having structure (VIII), a compound having structure (IV), and water, wherein the molar ratio of structure (VIII): structure (IV): water is 1 : 0.01 to 20 : 1 to 30, 1 : 0.1 to 10 : 16, or 1 : 0.25 to 1 : 2 to 4. In some embodiments, the silica-based ceramic is derived from a single-phase mixture (e.g., a single-phase silica-containing precursor sol) comprising both a compound having structure (VIII) (e.g., TEOS) and a compound having structure (VI) (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising a compound having structure (VIII), a compound having structure (VI), and water, wherein the molar ratio of structure (VIII): structure (VI): water is 1 : 0.01 to 10 : 1 to 30, 1 : 0.1 to 10 : 2 to 20, or 1 : 0.20 to 1 : 2 to 15.

[0118] In some embodiments, the silica-based ceramic is derived from a mixture comprising two or more precursors (e.g., a silicon-containing precursor sol). For example, in some embodiments, the silica-based ceramic is derived from a mixture comprising a compound having structure (VIII) (e.g., TEOS) and a compound having structure (IV) (e.g., (3-chloropropyl)triethoxysilane), wherein the mass ratio of structure (VIII) : structure (IV) is less than or equal to 99: 1, less than or equal to 95:5, less than or equal to 90: 10, less than or equal to 85: 15, less than or equal to 80:20, less than or equal to 75:25, less than or equal to 70:30, less than or equal to 65:35, less than or equal to 60:40, or less. In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising a compound having structure (VIII) (e.g., TEOS) and a compound having structure (IV) (e.g., (3-chloropropyl)triethoxysilane), wherein the mass ratio of structure (VIII) : structure (IV) is greater than or equal to 50:50, greater than or equal to 55:45, greater than or equal to 60:40, greater than or equal to 65:35, greater than or equal to 70:30, or greater. Combinations of these ranges are possible (e.g., greater than or equal to 50:50 and less than or equal to 99: 1, greater than or equal to 60:40 and less than or equal to 90: 10, or greater than or equal to 70:30 and less than or equal to 80:20).

[0119] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising a compound having structure (VIII) (e.g., TEOS) and a compound having structure (VI) (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium) wherein the mass ratio of structure (VIII) : structure (VI) is less than or equal to 99: 1, less than or equal to 95:5, less than or equal to 90: 10, less than or equal to 85: 15, less than or equal to 80:20, less than or equal to 75:25, less than or equal to 70:30, less than or equal to 65:35, less than or equal to 60:40, or less. In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silica-containing precursor sol) comprising a compound having structure (VIII) (e.g., TEOS) and a compound having structure (VI) (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium) wherein the mass ratio of structure (VIII) : structure (VI) is greater than or equal to 40:60, greater than or equal to 45:55, greater than or equal to 50:50, greater than or equal to 55:45, greater than or equal to 60:40, greater than or equal to 65:35, greater than or equal to 70:30, or greater. Combinations of these ranges are possible (e.g., greater than or equal to 40:60 and less than or equal to 99: 1, greater than or equal to 60:40 and less than or equal to 90: 10, or greater than or equal to 70:30 and less than or equal to 80:20).

[0120] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising an aqueous solution having a particular pH depending on the desired chemistry used. In some embodiments, the pH of the aqueous solution can be greater than or equal to -1, greater than or equal to 0, greater than or equal to 1, greater than or equal to 2, greater than or equal to 3, greater than or equal to 4, greater than or equal to 5, greater than 6, greater than or equal to 7, greater than or equal to 8, greater than or equal to 9, or higher. In some embodiments, the pH of the aqueous solution can be less than or equal to 14, less than or equal to 13, less than or equal to 12, less than or equal to 11, less than or equal to 10, less than or equal to 9, less than or equal to 8, less than or equal to 7, less than or equal to 6, less than or equal to 5, less than or equal to 4, less than or equal to 3, or lower. Combinations of these ranges are possible. For example, in some embodiments, the pH of the aqueous solution is greater than or equal to -1 and less than or equal to 14, greater than or equal to 0 and less than or equal to 7, or greater than or equal to 1 and less than or equal to 3. In some cases, having a relatively acidic pH (e.g., a pH of 1 to 3) can allow certain condensation and hydrolysis reactions to occur during the manufacture of a cation exchange membrane involving a sol-gel conversion to a silica-based ceramic. In some embodiments, the silica-based ceramic is derived from the above-described mixture (e.g., a silicon-containing precursor sol) comprising one or more acids such as, but not limited to, HC1, H3P04, H2S04, or HN03.

[0121] In some, but not necessarily all, embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising one or more other solvents in addition to water. For example, in some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising an alcohol. In some such cases, the presence of an alcohol in the mixture can enhance miscibility of the mixture components. Exemplary alcohols that can be present include, but are not limited to, methanol, ethanol, isopropanol, butanol, or combinations thereof. In some embodiments, for example, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising methanol (e.g., in some cases where TMAPS is used as a precursor). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising one or more solvents that can be capable of mitigating problems (e.g., cracking) that can occur during, for example, drying a coating layer comprising the mixture to form a silica-based ceramic. In some embodiments, exemplary solvents that can mitigate such problems include, but are not limited to, formamide and aromatic compounds (e.g., toluene, xylene).

[0122] As noted above, in some embodiments, the silica-based ceramic is porous. In some such embodiments, the silica-based ceramic is nanoporous (having pores with an average (mean) diameter of less than or equal to 10 nm). In some cases, the presence of relatively small pores in the silica-based ceramic can be advantageous in many applications, such as electrochemical applications and separation applications. In some embodiments, the presence of relatively small pores in the silica-based ceramic membrane can contribute to a relatively high selectivity of the anion exchange membrane (e.g., due to size exclusion). The relatively small pores can also contribute to a useful balance between relatively high permselectivity and anion conductivity (e.g., chloride conductivity) versus water transport. In some embodiments, the average pore size of the silica-based ceramic is less than or equal to 1 pm (e.g., less than or equal to 500 nm, less than or equal to 100 nm, or less than or equal to 50 nm). In some cases, the average pore size of the silica-based ceramic is less than or equal to 10 nm, less than or equal to 8 nm, less than or equal to 6 nm, less than or equal to 5 nm, less than or equal to 3 nm, less than or equal to 2 nm, or less. In some embodiments, the average pore size of the silica-based ceramic is greater than or equal to 0.25 nm, greater than or equal to 0.4 nm, greater than or equal to 0.6 nm, or greater than or equal to 1 nm. Combinations of these ranges are possible. For example, in some embodiments, the average pore size of the silica-based ceramic is greater than or equal to 0.25 nm and less than or equal to 1 pm, greater than or equal to 0.25 nm and less than or equal to 10 nm, greater than or equal to 0.4 nm and less than or equal to 10 nm, greater than or equal to 0.6 nm and less than or equal to 5 nm, or greater than or equal to 0.6 nm and less than or equal to 2.5 nm.

[0123] The average pore size of the silica-based ceramic can be determined using small angle X-ray scattering (SAXS) techniques. In suitable SAXS techniques, a collimated X-ray beam is focused on a membrane comprising the silica-based ceramic for at least 15 minutes, and the scattered intensity as a function of scattering angle is collected on an imaging plate. The scattered intensity is integrated to generate a 1 -dimensional scattering profile plotting the scattered intensity as a function of the q-vector. The scattering of the membrane can be fit with a spherical-based form factor (e.g., solid or core-shell). In some cases, the spherical-based form factor can include a structural factor (e.g., fractal or hard sphere interactions). The fit can be performed in the freely available SASView software. It is assumed that the pore size polydispersity is lognormal. The 1-D SAXS profile is well fit if the residual (Chi 2 ) between the model and data set is less than or equal to 10, less than or equal to 1, less than or equal to 0.5, or less. Certain parameters remain constant during the fit, including and where SLD is the scattering length density. SAXS fitting can be used to determine the volume fraction of porosity, the pore size (e.g., average pore diameter), and the polydispersity index of the pore size distribution. Suitable SAXS procedures are described in more detail in, e.g., Pedersen, J.S. Analysis of small-angle scattering data from colloids and polymer solutions: modeling and least-squares fitting. Advances in Colloid and Interface Science 1997, 70, 171-210, and in Zemb., T.; Lindner, P. Neutron, X-Rays and Light. Scattering Methods Applied to Soft Condensed Matter. North Holland: 2002, the entire contents of which are incorporated herein by reference. Average pore diameter can also be determined using other small angle scattering techniques, such as small angle neutron scattering (SANS).

[0124] In some embodiments, the anion exchange membrane or anion exchange material has a relatively large volumetric porosity. The volumetric porosity can depend on the porosity of the silica-based ceramic. Having a relatively high volumetric porosity can contribute to certain beneficial performance characteristics of the anion exchange membrane, such as anion exchange capacity and water uptake. In some embodiments, the volumetric porosity of the anion exchange membrane or anion exchange material is greater than or equal to 1%, greater than or equal to 3%, greater than or equal to 5%, greater than or equal to 10%, greater than or equal to 20%, greater than or equal to 30%, greater than or equal to 40%, or greater. In some embodiments, the volumetric porosity of the anion exchange membrane or anion exchange material is less than or equal to 70%, less than or equal to 60%, less than or equal to 50%, less than or equal to 45%, less than or equal to 40%, less than or equal to 35%, less than or equal to 30%, less than or equal to 25%, less than or equal to 15%, or less. Combinations of these ranges are possible. For example, in some embodiments, the volumetric porosity of the anion exchange membrane or anion exchange material is greater than or equal to 1% and less than or equal to 70%, greater than or equal to 5% and less than or equal to 50%, greater than or equal to 10% and less than or equal to 50%, or greater than or equal to 30% and less than or equal to 50%. As described above, these volumetric porosities of the anion exchange membrane or anion exchange material are determined via fitting of SAXS data of the anion exchange membrane or anion exchange material.

[0125] In some embodiments, the pores of the silica-based ceramic have a relatively small aspect ratio (length:width). The aspect ratio of the pores of the silica-based membrane can be determined by fitting SAXS data to an ellipsoid model to determine the average first radius and average second radius of the pores of the silica-based membrane, and taking the ratio of the average first radius and average second radius. In some embodiments, the aspect ratio of the pores of the silica-based membrane is less than or equal to 40: 1, less than or equal to 20: 1, less than or equal to 10: 1, less than or equal to 5: 1, or less.

[0126] In some embodiments, the pores of the silica-based ceramic have an ordered structure. In some cases, such an ordered structure can be contrasted with the pores of certain existing anion exchange membranes (e.g., those made from hydrocarbon-based polymers or perfluorocarbon-based polymers) that can have disordered pores (e.g., with high polydispersity) that can have a worm-like shape. In some cases, a silica-based ceramic with pores that have a regular, ordered structure at a relatively large size scale can correspond to improved performance characteristics in anion exchange applications. If the scattering data from a SAXS experiment on a membrane or material comprising a silica-based ceramic can be fit to a mathematical model with a Chi 2 value of less than or equal to 10, less than or equal to 5, less than or equal to 1, less than or equal to 0.5, or less, the pores of the silica-based ceramic have an ordered structure. Using the intensity (I) of the SAXS data as a function of the scattering vector q, an exemplary fractal aggregation model is as follows: 2 where S(q) is the network or fractal structure that defines the organization or architecture of the structural units of the pore network of the silica-based ceramic. In other words, in some embodiments, the structural units are the pores of the silica-based ceramic. Bck defines the background scattering, e.g., inelastic scattering out of the scattering particles and / or from the scattering particles source and the silica-based ceramic. In some embodiments, S(q) is defined by the following equation:

[0127] I(q) = P(q)S(q) + bck

[0128] where S(q) is the network or fractal structure that defines the organization or architecture of the structural units of the pore network of the silica-based ceramic. In other words, in some embodiments, the structural units are the pores of the silica-based ceramic. Bck defines the background scattering, e.g., inelastic scattering out of the scattering particles and / or from the scattering particles source and the silica-based ceramic. In some embodiments, S(q) is defined by the following equation:

[0129]

[0130] where

[0131] R o is the radius of the structural units (pores), p 溶剂 is the scattering length density of the solvent (silica-based ceramic), p 单元D is the scattering length density of the structural units (if the film is dry, it is assumed to be the scattering length density of air at ambient conditions), f is the fractal dimension, ξ is the correlation length, and Γ is the standard mathematical gamma function.

[0132] P(q) is a form factor as a function of q that defines the structure of the structural units of the pore network of the silica-based ceramic. Such form factors can take a variety of shapes, for example simple geometric shapes such as spheres, ellipsoids, cubes, ovals, and the like.

[0133] In some embodiments, the structural units (pores) are defined as uniform structural units, for example uniform spheres. In this regard, in some embodiments, P(q) is defined by the following equation:

[0134] P(q) = proportionality x V(p 单元 - p 溶剂 ) 2 F(qR0) 2 ,

[0135] where

[0136]

[0137]

[0138] proportionality is the volume fraction of the structural units of the silica-based ceramic that is measured.

[0139] In some embodiments, the form factor defines a spherical core-shell structural unit (pore). In some such embodiments, aspect, P(q) is defined by the following equation:

[0140]

[0141] where

[0142] proportionality is the volume fraction of the structural units of the silica-based ceramic that is measured, V c is the volume of the core, V s is the volume of the shell, p c is the scattering length density of the core, p s is the scattering length density of the shell (e.g., the shell of functional groups), p 单元 is the scattering length density of the structural unit (pore), r c is the radius of the core, r s is the radius of the shell, and bck is the background scattering.

[0143] In some embodiments, one or more surfaces of the silica-based ceramic are coated with an additional coating. A core-shell model, such as a core-shell fractal aggregation model, can be suitable for characterizing the core-shell particle structure unit. In some cases, the core-shell model is suitable even without an additional coating process. For example, in some embodiments, the method for forming the silica-based ceramic (e.g., a sol-gel based method) produces phase separation regions that can be modeled using a core-shell model.

[0144] As described above, different embodiments of the form factor P(q) of the fractal aggregation model used to characterize the small angle scattering spectrum can include a factor that accounts for the difference in scattering length density.

[0145] In some embodiments, the scattering length density in the above equation is defined by the material of the components that make up the silica-based ceramic membrane. Generally, a large difference between the scattering length density of the scattering source (e.g., the pores) and the surrounding ceramic material provides a large scattering contrast. Thus, in some embodiments, the small angle scattering data is generated from a silica-based ceramic that has been dried to remove solvent or other liquid from the pores, thus providing a greater difference in scattering length density compared to a silica-based ceramic with pores filled with liquid solvent.

[0146] In some embodiments, the scattering length density is defined in units of (Angstroms squared inverse). The scattering length density is defined as the sum of the bound coherent scattering lengths of individual atoms normalized by the molecular volume. For example, the X-ray scattering length density of air is about whereas the X-ray scattering length density of amorphous silica is about

[0147] In some embodiments, the small angle scattering data is generated from a silica-based ceramic that has been rinsed to remove residual ions, chemical reactants, etc.

[0148] In some embodiments, fitting the small angle scattering spectrum to the fractal aggregation model includes fitting the small angle scattering spectrum over a range of q values that exceeds one order of magnitude, such as more than one order of magnitude, where q is in units of In addition to providing sufficient data to fit with the fractal aggregation model, such a relatively wide range of fitting can ensure that the data is fit to the fractal aggregation model over a range of sizes that is commensurate with the range of sizes of, for example, the pores of the silica-based ceramic. In some embodiments, fitting the small angle scattering spectrum to the fractal aggregation model includes fitting the small angle scattering spectrum over a range of q values in the range of about to about In some embodiments, fitting the small angle scattering spectrum to the fractal aggregation model includes fitting the small angle scattering spectrum over a range of q values in the range of about up to about Small angle scattering spectra are fitted over a range of q values within the range.

[0149] As noted above, the ratio corresponds to the volume fraction of pores in the silica-based ceramic. In some embodiments, when the intensity units of the small angle scattering spectrum are 1 / cm and the ratio is less than 0.7, the ratio corresponds to the porosity of the membrane. In this regard, the ratio corresponds to the number of pores normalized by the sample size. In some embodiments, the silica-based ceramic has a porosity volume fraction in the range of about 0.01 to about 0.7. In some embodiments, the silica-based ceramic has a porosity volume fraction in the range of about 0.15 to about 0.35. It should be understood that the above ranges correspond to the case where the scattering length density refers to that of air for the pores and amorphous silica for the silica-based ceramic, respectively, under ambient conditions.

[0150] In some embodiments, D f is a fractal dimension of the fractal aggregation model described herein. In some embodiments, D f corresponds to the shape and / or configuration of the pores within the silica-based ceramic. Generally, D f is in the range of about 1 to about 3. In the case where Df is close to or is 1, the pores can generally be characterized as 1 -dimensional channels. In the case where D f is close to or is 3, the pores can generally be characterized as open spheres.

[0151] In some embodiments, it is advantageous to have a silica-based ceramic that defines pores having a tortuous or indirect path through the silica-based ceramic. For ions or other particles that are in fluid communication with the tortuous pores, the ions or other particles will be less likely to pass through the membrane when the size of the ions or other particles is close to the size of the tortuous pores, as compared to less tortuous pores. In this regard, in some cases, such a silica-based ceramic that defines tortuous pores can be better suited to provide, for example, a more selective anion exchange than, for example, a silica-based ceramic that defines pores of the same size but that provides a more direct path through the silica-based ceramic. In this regard, in some but not necessarily all embodiments, D f is in the range of 2.0 to 4.0. Such a D f range describes or characterizes a silica-based ceramic having pores that are relatively tortuous, with a shape factor that is intermediate between a straight line and an open sphere.

[0152] In some embodiments, the fractal aggregation model is restricted to have pore sizes within a particular range. As described above, the porous support defines pores having an average pore size within the above-described range. Likewise, the methods described in the present disclosure are suitable for making such silica-based ceramics that define pores within such a size range. Thus, by constraining the fractal aggregation model used to fit the small angle scattering data, a good fit between the fractal silica-based ceramic and the fractal aggregation model can be obtained.

[0153] As described above, the correlation length ξ is the length over which the fractal pattern of the silica-based ceramic repeats itself. In some cases, the silica-based ceramic will repeat the fractal pattern over a relatively large size scale. In this regard, such silica-based ceramics define regular, ordered pores over a relatively large size scale, which in some cases can correspond to improved functional properties, e.g., filtration, ion exchange, etc. Similarly, the fractal pattern generally cannot extend to size scales smaller than the size scale of the structural units of the silica-based ceramic, e.g., smaller than the size scale of a molecule or atom. Thus, in some embodiments, the correlation length ξ is restricted to a value greater than 1 nm. In some embodiments, the correlation length ξ is restricted to a value greater than 50 nm. In some embodiments, the correlation length ξ is restricted to a value greater than 100 nm. In some embodiments, the correlation length ξ is restricted to a value on the order of the thickness of the silica-based ceramic. In some embodiments, the silica-based ceramic has a correlation length ξ greater than 1 nm, e.g., greater than 50 nm or greater than 100 nm.

[0154] The fractal aggregation model used to characterize the silica-based ceramic can include a term that accounts for variability in the size of the scattering sources (e.g., the pores of the silica-based ceramic). In this regard, in some embodiments, the fractal aggregation model includes a polydispersity index for the radius parameter. Thus, in some embodiments, the radius R of the structural units O is a weighted average rather than a constant. The weighted average can be according to a number of mathematical functions, e.g., a Gaussian function, a log-normal function, a rectangular distribution, etc. In some embodiments, the polydispersity index is Gaussian and according to the equation:

[0155]

[0156] where x 平均 is the mean of the distribution (the average radius), Norm is a normalization factor determined during the numerical calculation, and the polydispersity index is the ratio of σ / x 平均 .

[0157] In some embodiments, the polydispersity ratio is log-normal and according to the equation:

[0158]

[0159] where p is the polydispersity index, μ = ln(x med ), x med is the median of the distribution, and Norm is a normalization factor determined during numerical calculations.

[0160] In some embodiments, log-normal distributions are advantageous because they are generally asymmetric about x med In this regard, as the polydispersity ratio increases, the lower tail can not fall within the physically defined range, for example those that would define pore sizes smaller than, for example, atoms that physically define the pores.

[0161] In some embodiments, the pores of the silica-based ceramic have a log-normal polydispersity index of pore radius that is relatively low. Having a log-normal polydispersity index of pore radius that is relatively low generally corresponds to pores having a relatively similar radius, which can indicate a regular, ordered structure of the pores of the silica-based ceramic. In some embodiments, the pores of the silica-based ceramic have a log-normal polydispersity index of pore radius that is less than or equal to 0.8, less than or equal to 0.7, less than or equal to 0.5, less than or equal to 0.3, or less. In some embodiments, the pores of the silica-based ceramic have a log-normal polydispersity index of pore radius that is greater than or equal to 0 and less than or equal to 0.8, greater than or equal to 0 and less than or equal to 0.7, greater than or equal to 0 and less than or equal to 0.5, greater than or equal to 0 and less than or equal to 0.3.

[0162] In some embodiments, the pores of the silica-based ceramic conform to the Teubner-Strey model. The Teubner-Strey model was originally developed to describe the scattering patterns and microstructure of microemulsions (e.g., mixtures of water, oil, and amphiphiles). Small angle scattering experiments, such as small angle neutron scattering (SANS) experiments, have unexpectedly revealed, in embodiments, that ion exchange membranes or ion exchange materials have silica-based ceramic pore structures that conform to this Teubner-Strey model. The Teubner-Strey ordering is more commonly associated with micellar structures in which micelles perform a well-defined pore structure and pore-pore distance rather than the packed micellar structures observed herein for the ceramic-based structures.

[0163] When the pores of the silica-based ceramic conform to the Teubner-Strey model of the small angle scattering spectrum, the intensity (I) as a function of the scattering vector q conforms to the following equation:

[0164]

[0165] where a, c1, and c2 are adjustable parameters, and bck is the background scattering. If scattering data from a small angle scattering experiment (e.g., small angle neutron scattering, SANS) on a film or material comprising a silica-based ceramic can be fit to a Teubner-Strey model with Chi 2 / N value less than or equal to 10, less than or equal to 5, less than or equal to 1, less than or equal to 0.5, or less, the pores of the silica-based ceramic can conform to a Teubner-Strey model, where Chi 2 is the sum of the squared differences in intensity between the mathematical model and the small angle scattering spectral data, and N is the number of points of the small angle scattering data points in the model fitting range. N can be, for example, at least 30, at least 50, at least 100, at least 200, at least 500, and / or up to 1,000, up to 2,000, or more points in the model fitting range. In some embodiments, the model fitting range of q is from to or to

[0166] Teubner-Strey fitting of the small angle scattering of the pores of the silica-based ceramic can also provide a measure of the domain size d (periodicity) and the correlation length ξ according to the following equations:

[0167]

[0168]

[0169]

[0170]

[0171] where <η 2> is the mean square of the medium scattering density fluctuations, y(r) is the real space correlation function corresponding to I(q), and k = 2π / d. In the context of anion exchange membranes or anion exchange materials, ξ corresponds to the pore radius of the silica-based ceramic, and d corresponds to the pore-pore distance measured from the centers of two separate nearest neighbor pores of the silica-based ceramic. Further description of the Teubner-Strey model and its application in small angle scattering measurements can be found in Schubert, K. V., Strey, R., Kline, S. R., & Kaler, E. W. (1994). Small angle neutron scattering near Lifshitz lines: Transition from weakly structured mixtures to microemulsions. The Journal of Chemical Physics, 101(6), 5343-5355 and Teubner, M., & Strey, R. (1987). Origin of the scattering peak in microemulsions. The Journal of Chemical Physics, 87(5), 3195-3200, each of which is incorporated by reference herein in its entirety for all purposes.

[0172] In some, but not necessarily all, embodiments, the structure of the pores of the silica-based ceramic depends on the state of the anion exchange membrane or anion exchange material. For example, whether the anion exchange is in a dry state or a hydrated state can in some cases affect the pore structure of the silica-based ceramic. When the anion exchange membrane or anion exchange material is in a first state (e.g., a dry state), the pores of the silica-based ceramic can conform to a first mathematical model of small angle scattering spectra, and when the anion exchange membrane or anion exchange material is in a different second state (e.g., a hydrated state), the pores of the silica-based ceramic can conform to a different second mathematical model of small angle scattering spectra. In this context, the anion exchange membrane or anion exchange material is considered to be in a dry state when it has been heated in an oven at 100 °C and 0% relative humidity for 2 hours, and it is considered to be in a hydrated state when it is immersed in H2O or D2O at room temperature for 24 hours in a vacuum environment (with air being pulled out of the pores but not to a reduced pressure that causes H2O or D2O to boil).

[0173] As another example, in some, but not necessarily all, embodiments, the average pore size of the silica-based ceramic is greater when the anion exchange membrane or anion exchange material is in a hydrated state than when the anion exchange membrane or anion exchange material is in a dry state. It has been observed that an average pore size in a hydrated state that is greater than an average pore size in a dry state can cause a penetration of the hydration domain in the silica-based ceramic. Such penetration can cause improved anion transport properties (e.g., chloride ion conductivity). In some embodiments, the average pore size of the silica-based ceramic is greater when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state to a degree that is greater than or equal to 1.1 times, greater than or equal to 1.2 times, greater than or equal to 1.3 times, greater than or equal to 1.4 times, greater than or equal to 1.5 times, greater than or equal to 1.6 times, greater than or equal to 1.8 times, greater than or equal to 2 times, or greater when in the dry state. In some embodiments, the average pore size of the silica-based ceramic is greater when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state to a degree that is less than or equal to 5 times, less than or equal to 4.5 times, less than or equal to 4 times, less than or equal to 3.5 times, less than or equal to 3 times, less than or equal to 2.8 times, less than or equal to 2.6 times, less than or equal to 2.5 times, less than or equal to 2.4 times, less than or equal to 2.3 times, less than or equal to 2.2 times, less than or equal to 2.1 times, less than or equal to 2 times, or less when in the dry state. Combinations of the ranges are possible. For example, in some embodiments, the average pore size of the silica-based ceramic is greater when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state to a degree that is greater than or equal to 1.1 times and less than or equal to 5 times, or greater than or equal to 1.3 times and less than or equal to 3 times thereof when in the dry state.

[0174] As another example, in some, but not necessarily all, embodiments, the pores of the silica-based ceramic conform to the Teubner-Strey model of the small angle scattering spectrum as described above when the anion exchange membrane or anion exchange material is in a dry state, and the pores of the silica-based ceramic conform to the core-shell model of the small angle scattering spectrum as described above when the anion exchange membrane or anion exchange material is in a hydrated state. It has been observed that, in some embodiments, having a Teubner-Strey ordering in the dry state and a core-shell structure in the hydrated state is associated with a structural change upon water uptake that imparts beneficial performance properties (e.g., anion exchange capacity, anion conductivity, permselectivity, etc.).

[0175] In some embodiments, the pore structure of the silica-based membrane that depends on the state of the anion exchange membrane or anion exchange material can depend on the composition of the silica-based membrane or material and / or the conditions under which the anion exchange membrane or anion exchange material is made. For example, the dependence of the pore structure on the state of the anion exchange membrane or anion exchange material (e.g., when dry versus when hydrated) can depend on the amount of functional groups (e.g., quaternary ammonium groups) present in the silica-based ceramic. The amount of functional groups present, in turn, can depend on the ratio of silicon-containing precursors in the silicon-containing precursor sol, for example, during the making of the anion exchange membrane or anion exchange material. In some embodiments, an anion exchange membrane derived from a silicon-containing precursor sol having a relatively small amount (e.g., less than or equal to 5 mol%, less than or equal to 1 mol%, or less) of silicon-containing precursors comprising functional groups (e.g., having structure IV or VI) has a relatively similar pore structure (e.g., average pore diameter, small angle scattering model fit) whether the anion exchange membrane or anion exchange material is in a dry state or a hydrated state. For example, in some such cases, the average pore diameter in the hydrated state is within 10%, within 5%, or within 2% of the average pore diameter in the dry state. However, in some embodiments, an anion exchange membrane derived from a silicon-containing precursor sol having a relatively large amount (e.g., greater than or equal to 15 mol%, greater than or equal to 20 mol%, greater than or equal to 25 mol%, greater than or equal to 30 mol%, greater than or equal to 35 mol%, greater than or equal to 40 mol%, or greater) of silicon-containing precursors comprising functional groups (e.g., having structure IV or VI) has a pore structure (e.g., average pore diameter, small angle scattering model fit) that is substantially different when the anion exchange membrane or anion exchange material is in a dry state than when it is in a hydrated state (e.g., the pore diameter in the hydrated state is greater than or equal to 1.1 times, greater than or equal to 1.2 times, greater than or equal to 1.3 times, greater than or equal to 1.4 times, greater than or equal to 2 times, or greater than the pore diameter in the dry state).

[0176] As noted above, in some embodiments, the anion exchange membrane includes a porous support membrane. The porous membrane (e.g., the porous support membrane 130) can include any of a variety of suitable materials and can be in any of a variety of forms.

[0177] In some embodiments, the porous support membrane includes relatively large pores in the absence of the silica-based ceramic, e.g., prior to being coated with the silica-based ceramic. For example, referring back to FIG. 1, the porous support membrane 130 includes pores 132 that are relatively large (e.g., greater than or equal to 1 nm, greater than or equal to 2 nm, greater than or equal to 5 nm, greater than or equal to 10 nm, greater than or equal to 20 nm, greater than or equal to 50 nm, or greater) in the absence of the silica-based ceramic. Figure 2APorous support membrane 130 includes pores that include relatively large pores 132. In some embodiments, having relatively large pores can enable sufficient overall transmembrane permeability and sufficient space for the presence of silica-based ceramic in the event that a coating formed from silica-based ceramic is at least partially within the porous support membrane. In some embodiments, in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic, the porous support membrane includes pores having an average (average / mean) pore size greater than or equal to 50 nm, greater than or equal to 75 nm, greater than or equal to 100 nm, greater than or equal to 200 nm, greater than or equal to 500 nm, greater than or equal to 1 pm, greater than or equal to 2 pm, greater than or equal to 5 pm, greater than or equal to 10 pm, greater than or equal to 15 pm, greater than or equal to 20 pm, greater than or equal to 30 pm, greater than or equal to 40 pm, or greater. In some embodiments, however, the porous support membrane does not include pores that are so large as to cause a deleterious effect on the performance or characteristics of the anion exchange membrane, e.g., poor mechanical rupture strength, low coating retention, etc. In some embodiments, in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic, the porous support membrane includes pores having an average pore size less than or equal to 50 pm, less than or equal to 25 pm, less than or equal to 10 pm, less than or equal to 5 pm, less than or equal to 2 pm, less than or equal to 1 pm, less than or equal to 500 nm, or less. Combinations of these ranges are possible. For example, in some embodiments, in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic, the porous support membrane includes pores having an average diameter greater than or equal to 50 nm and less than or equal to 50 pm, greater than or equal to 500 nm and less than or equal to 10 pm, or greater than or equal to 1 pm and less than or equal to 5 pm. The average pore size of the porous support membrane in the anion exchange membrane can be determined by Brunauer-Emmett-Teller (BET) gas adsorption techniques or mercury porosimetry.

[0178] It is to be understood that in some embodiments, the silica-based ceramic, when present, fills at least a portion (or all) of the pores of the porous support membrane. In such cases, the average pore size of the porous support membrane in the final anion exchange membrane will be smaller than the average pore size of the porous support membrane prior to being coated with the silica-based ceramic. Additionally and as noted above, in some embodiments, the silica-based ceramic is itself porous (e.g., nanoporous). Thus, in some embodiments, the anion exchange membrane has a bimodal distribution of pores. For example, in some embodiments, the anion exchange membrane has a bimodal distribution of pores comprising relatively small pores corresponding to the pores of the silica-based ceramic and relatively large pores corresponding to the partially filled (e.g., 70% filled) pores of the porous support membrane. In these embodiments, the bimodal distribution can be determined by measuring the relatively small pores (e.g., measuring the pores corresponding to the silica-based ceramic) using the SAXS technique described above and measuring the relatively large pores (e.g., measuring the pores corresponding to the partially filled pores of the porous support membrane) using the BET gas adsorption or mercury porosimetry techniques described above.

[0179] In some embodiments, the average pore size of the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) is less than or equal to 1 pm (e.g., less than or equal to 500 nm, less than or equal to 100 nm, or less than or equal to 50 nm). In some cases, the average pore size of the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) is less than or equal to 10 nm, less than or equal to 8 nm, less than or equal to 6 nm, less than or equal to 5 nm, less than or equal to 3 nm, less than or equal to 2 nm, or less. In some embodiments, the average pore size of the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) is greater than or equal to 0.25 nm, greater than or equal to 0.4 nm, greater than or equal to 0.6 nm, or greater than or equal to 1 nm. Combinations of these ranges are possible. For example, in some embodiments, the average pore size of the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) is greater than or equal to 0.25 nm and less than or equal to 1 pm, greater than or equal to 0.25 nm and less than or equal to 10 nm, greater than or equal to 0.4 nm and less than or equal to 10 nm, greater than or equal to 0.6 nm and less than or equal to 5 nm, or greater than or equal to 0.6 nm and less than or equal to 2.5 nm.

[0180] In some embodiments, the average pore size of the relatively large pores of the bimodal distribution (e.g., corresponding to the partially filled pores of the porous support membrane) is greater than or equal to 50 nm, greater than or equal to 75 nm, greater than or equal to 100 nm, greater than or equal to 200 nm, greater than or equal to 500 nm, greater than or equal to 1 μιη, greater than or equal to 2 μιη, greater than or equal to 5 μιη, greater than or equal to 10 μιη, greater than or equal to 15 μιη, greater than or equal to 20 μιη, greater than or equal to 30 μιη, greater than or equal to 40 μιη, or greater. In some embodiments, the average pore size of the relatively large pores of the bimodal distribution (e.g., corresponding to the partially filled pores of the porous support membrane) is less than or equal to 50 μιη, less than or equal to 25 μιη, less than or equal to 10 μιη, less than or equal to 5 μιη, less than or equal to 2 μιη, less than or equal to 1 μιη, less than or equal to 500 nm, or less. Combinations of these ranges are possible. For example, in some embodiments, the average pore size of the relatively large pores of the bimodal distribution (e.g., corresponding to the partially filled pores of the porous support membrane) is greater than or equal to 50 nm and less than or equal to 50 μιη, greater than or equal to 500 nm and less than or equal to 10 μιη, or greater than or equal to 1 μιη and less than or equal to 5 μιη.

[0181] In some embodiments, the porous support membrane has a relatively high volumetric porosity in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic. In some cases, having a relatively high volumetric porosity can enable sufficient overall permeability as well as sufficient space for silica-based ceramic to exist in the event that a coating formed from silica-based ceramic is at least partially within the porous support membrane. In some embodiments, the volumetric porosity of the porous support membrane in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic, is greater than or equal to 10%, greater than or equal to 15%, greater than or equal to 20%, greater than or equal to 30%, greater than or equal to 40%, greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, greater than or equal to 80%, greater than or equal to 90%, or greater. In some embodiments, the volumetric porosity of the porous support membrane in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic, is less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 80%, less than or equal to 70%, less than or equal to 60%, less than or equal to 50%, less than or equal to 40%, less than or equal to 30%, or less. Combinations of these ranges are possible. For example, in some embodiments, the volumetric porosity of the porous support membrane in the absence of silica-based ceramic, e.g., prior to coating with silica-based ceramic, is greater than or equal to 10% and less than or equal to 99%, greater than or equal to 50% and less than or equal to 99%, greater than or equal to 80% and less than or equal to 99%, or greater than or equal to 60% and less than or equal to 80%. It will be appreciated that, in some embodiments, the silica-based ceramic fills at least some of the pores of the porous support membrane. Thus, in some embodiments, the volumetric porosity of the entire anion exchange membrane can be different from the volumetric porosity of the porous support membrane in the absence of silica-based ceramic. The volumetric porosity of the porous support membrane in the anion exchange membrane can be determined by BET gas adsorption techniques or mercury porosimetry.

[0182] The porous support membrane can have any suitable cross-sectional thickness. In some cases, having a suitable cross-sectional thickness can allow the porous support membrane and the final anion exchange membrane (e.g., by having appropriate permeability and ion transport rates) to have suitable mechanical (e.g., mechanical burst strength) and performance characteristics. In some embodiments, the porous support membrane has a cross-sectional thickness of greater than or equal to 3 pm, greater than or equal to 5 pm, greater than or equal to 10 pm, greater than or equal to 25 pm, greater than or equal to 50 pm, greater than or equal to 75 pm, greater than or equal to 100 pm, greater than or equal to 150 pm, greater than or equal to 200 pm, greater than or equal to 300 pm, greater than or equal to 400 pm, greater than or equal to 500 pm, or greater. In some embodiments, the porous support membrane has a cross-sectional thickness of less than or equal to 1,000 pm, less than or equal to 500 pm, less than or equal to 300 pm, less than or equal to 100 pm, or less. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane has a cross-sectional thickness of greater than or equal to 3 pm and less than or equal to 1,000 pm, or greater than or equal to 25 pm and less than or equal to 300 pm. The cross-sectional thickness of the porous support membrane in the anion exchange membrane can be determined using SEM / EDX techniques on the anion exchange membrane. In some embodiments, the EDX portion of this technique can be used to distinguish the porous support membrane from other components of the anion exchange membrane, such as a silica-based ceramic.

[0183] The porous support membrane can be in any of a variety of suitable forms. It is therefore to be understood that Figure 2A The depictions of the porous support membrane 130 in FIGS. 1-3 are non-limiting and exemplary, and the porous support membrane 130 can be in the form of any suitable structure. In some embodiments, the porous support membrane can be in the form of a macro-porous structure. For example, in some embodiments, the porous support membrane is in the form of a non-woven fabric or non-woven web. In some embodiments, the porous support membrane is in the form of a veil. In some embodiments, the porous support membrane is in the form of a knitted fabric. In some cases, the porous support membrane is in the form of a woven fabric or web. In some embodiments, the porous support membrane is in the form of an open-cell structure, such as an open-cell foam. In some embodiments, the porous support membrane is in the form of a fibril and node structure. In some cases, the porous support membrane includes a combination of multiple types of micro-porous structures. For example, in some embodiments, the porous support membrane includes a combination of the exemplary structures described above (e.g., non-woven fabric, open-cell foam, etc.).

[0184] The porous support membrane can be formed by any suitable method. In some embodiments, the porous support membrane is a wet-laid structure or a non-wet-laid structure (e.g., air-laid structure, carded structure, melt-blown structure, melt-spun structure (e.g., spun-bond), centrifugal spun web, solvent-spun web, electrospun web, gel-spun web).

[0185] As described above, in some embodiments, the porous support membrane comprises a support component. The support component of a porous support membrane generally refers to a component of the porous support membrane that contributes to the overall structure and mechanical properties of the porous support membrane. For example, in some embodiments in which the porous support membrane is in the form of a nonwoven fabric, the support component of the nonwoven fabric can include the fibers and / or filaments that form the nonwoven fabric. As another example, in some embodiments in which the porous support membrane is in the form of a mesh, the support component of the mesh can include the strands that form the mesh. Examples of support components include, but are not limited to, fibers, strands, and threads. Again referring to Figure 2A According to some embodiments, the porous support membrane 130 comprises an exemplary porous support component 135.

[0186] In some embodiments, the support component has a relatively large number average diameter. In some cases, having a support component with a relatively large diameter can help the porous support membrane have relatively beneficial mechanical properties (e.g., relatively high mechanical burst strength). In some embodiments, the number average support component diameter (e.g., fiber diameter, pore diameter) of the porous support membrane is greater than or equal to 10 nm, greater than or equal to 25 nm, greater than or equal to 50 nm, greater than or equal to 100 nm, greater than or equal to 200 nm, greater than or equal to 500 nm, greater than or equal to 1 μιη, greater than or equal to 2 μιη, greater than or equal to 5 μιη, greater than or equal to 10 μιη, greater than or equal to 20 μιη, or greater. In some embodiments, the support component of the porous support membrane is not so large as to cause detrimental effects to the overall anion exchange membrane, such as insufficient porosity or permeability. In some embodiments, the number average support component diameter (e.g., fiber diameter, pore diameter) of the porous support membrane is less than or equal to 50 μιη, less than or equal to 20 μιη, less than or equal to 10 μιη, less than or equal to 5 μιη, less than or equal to 2 μιη, less than or equal to 1 μιη, less than or equal to 500 nm, less than or equal to 100 nm, or less. Combinations of the ranges are possible. For example, in some embodiments, the number average support component diameter of the porous support membrane is greater than or equal to 10 nm and less than or equal to 50 μιη, greater than or equal to 10 nm and less than or equal to 20 μιη, greater than or equal to 100 nm and less than or equal to 1 μιη, or greater than or equal to 100 nm and less than or equal to 500 nm.

[0187] The porous support film can comprise any of a variety of suitable materials (e.g., organic materials, inorganic materials, or combinations thereof). In some embodiments, the porous support film comprises a polymeric material. In some such cases, the porous support film is composed of greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, greater than or equal to 70 wt%, greater than or equal to 75 wt%, greater than or equal to 80 wt%, greater than or equal to 90 wt%, greater than or equal to 95 wt%, or more by weight of one or more polymers. In some embodiments, the porous support film is composed of less than or equal to 100 wt%, less than or equal to 99 wt%, less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 80 wt%, less than or equal to 50 wt%, less than or equal to 30 wt%, or less by weight of one or more polymers. Combinations of these ranges are possible. For example, in some embodiments, the porous support film is composed of greater than or equal to 20 wt% and less than or equal to 100 wt%, or greater than or equal to 50 wt% and less than or equal to 99 wt% by weight of one or more polymers. Exemplary polymers that the porous support film can comprise include, but are not limited to, polyethylene, polyvinyl chloride, polypropylene, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyether ether ketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, microfibrillated cellulose, nanofibrillated cellulose, or combinations or derivatives thereof.

[0188] In some embodiments, the porous support membrane comprises a ceramic or glass material. In some such cases, the porous support membrane is greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, greater than or equal to 70 wt%, greater than or equal to 75 wt%, greater than or equal to 80 wt%, greater than or equal to 90 wt%, greater than or equal to 95 wt%, or more, by weight, of one or more ceramic or glass materials. In some embodiments, the porous support membrane is less than or equal to 100 wt%, less than or equal to 99 wt%, less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 80 wt%, less than or equal to 50 wt%, less than or equal to 30 wt%, or less, by weight, of one or more ceramic or glass materials. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane is greater than or equal to 20 wt% and less than or equal to 100 wt%, or greater than or equal to 50 wt% and less than or equal to 99 wt%, by weight, of one or more ceramic or glass materials. Exemplary ceramics that the porous support membrane can comprise include, but are not limited to, borosilicate glass, silica, titania, zirconia, alumina, silicon carbide, silicon nitride, boron nitride, lithium silicate, potassium silicate, tin oxide, iron oxide, or combinations thereof.

[0189] In some embodiments, the porous support membrane comprises a metal and / or metal alloy. In some such cases, the porous support membrane is greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, greater than or equal to 70 wt%, greater than or equal to 75 wt%, greater than or equal to 80 wt%, greater than or equal to 90 wt%, greater than or equal to 95 wt%, or more, by weight, of one or more metals and / or metal alloys. In some embodiments, the porous support membrane is less than or equal to 100 wt%, less than or equal to 99 wt%, less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 80 wt%, less than or equal to 50 wt%, less than or equal to 30 wt%, or less, by weight, of one or more metals and / or metal alloys. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane is greater than or equal to 20 wt% and less than or equal to 100 wt%, or greater than or equal to 50 wt% and less than or equal to 99 wt%, by weight, of one or more metals and / or metal alloys. Exemplary metals that the porous support membrane can comprise include, but are not limited to, iron, nickel, copper, titanium, aluminum, or combinations thereof. One non-limiting example of a metal alloy that the porous support membrane can comprise is steel.

[0190] In some embodiments, the porous support membrane comprises a combination of the above-described materials. For example, in some embodiments, the porous support membrane comprises a combination of a polymeric material and a ceramic or glass material (or a polymeric material and a metal and / or a metal alloy, or a ceramic material and a metal and / or a metal alloy). A non-limiting example is an embodiment in which the porous support membrane comprises a glass material (e.g., borosilicate glass) containing one or more polymeric materials (e.g., one or more polymeric binders that can enhance the mechanical properties of the porous support membrane).

[0191] In some, but not all, embodiments, the porous support membrane contains one or more amphiphilic molecules on its surface. In some cases, the presence of one or more amphiphilic molecules on the surface of the porous support membrane can promote enhanced wetting of the solution used during the manufacture of the anion exchange membrane. For example, in some cases, the anion exchange membrane is manufactured via applying a sol-gel solution to the porous support membrane. In some cases, such enhanced wetting can help reduce cracking during certain manufacturing steps (e.g., in the case of a drying step). In some such cases, the presence of one or more amphiphilic molecules on the surface of the porous support membrane can promote the wetting of the sol-gel ceramic material on the porous support membrane. In some cases, the amphiphilic molecules are covalently bonded to at least a portion of the porous support membrane (e.g., as surface functional groups). In some embodiments, the amphiphilic molecules are coated onto or within the porous support membrane (e.g., prior to coating the porous support membrane with a sol-gel). Exemplary amphiphilic molecules include, but are not limited to, sodium alkyl sulfate (e.g., sodium dodecyl sulfate), dialkyl sulfosuccinate, and alkyl trimethylammonium bromide.

[0192] In some embodiments, the porous support film has a relatively high surface area (e.g., before coating with a silica-based ceramic). In some cases, a relatively high surface area of ​​the porous support film can promote adhesion between the porous support film and the silica-based ceramic. An exemplary way to achieve a relatively high surface area of ​​the porous support film is by etching the porous support film before coating it with a silica-based ceramic. In some cases, the porous support film can be etched with a suitable solvent, acid, etchant, or oxidant. In some embodiments, the specific surface area of ​​the porous support film is greater than or equal to 0.0001 m² before coating with a silica-based ceramic. 2 / g, greater than or equal to 0.0002m 2 / g, greater than or equal to 0.0005m 2 / g, greater than or equal to 0.001m 2 / g, greater than or equal to 0.002m 2 / g, greater than or equal to 0.005m2 / g, greater than or equal to 0.01 m 2 / g, greater than or equal to 0.02 m 2 / g, greater than or equal to 0.05 m 2 / g, greater than or equal to 0.1 m 2 / g, greater than or equal to 0.2 m 2 / g, greater than or equal to 0.5 m 2 / g, or greater. In some embodiments, the porous support membrane has a specific surface area of less than or equal to 100 m 2 / g, less than or equal to 50 m 2 / g, less than or equal to 20 m 2 / g, less than or equal to 10 m 2 / g, less than or equal to 5 m 2 / g, less than or equal to 2 m 2 / g, less than or equal to 1 m 2 / g, or less. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane has a specific surface area of greater than or equal to 0.0001 m 2 / g and less than or equal to 100 m 2 / g, greater than or equal to 0.001 m 2 / g and less than or equal to 10 m 2 / g, or greater than or equal to 0.01 m 2 / g and less than or equal to 1 m 2 / g. The specific surface area of the porous support membrane prior to coating with the silica-based ceramic can be determined using BET gas adsorption techniques (prior to forming the silica-based ceramic coating, or by removing the silica-based ceramic from the anion exchange membrane).

[0193] In some embodiments, a relatively high percentage of the pore volume of the porous support membrane is filled with the silica-based ceramic that coats at least a portion of the porous support membrane. The percentage of the pore volume of the porous support membrane that is filled with the silica-based ceramic can be determined, for example, using SEM. Typically, several images are taken of both the top and cross-section of the anion exchange membrane at different magnifications from 200x of the top to 2000x of the cross-section. These images can be compared to images of the porous support membrane at the same magnifications. To determine the extent to which the pore volume of the porous support membrane is filled with the silica-based ceramic, the cross-section of the anion exchange membrane is examined. An anion exchange membrane in which the pore volume of the porous support membrane is sufficiently filled with the silica-based ceramic will appear dense with little to no apparent macropores or open areas. In some cases, if there are less dense places (e.g., cracks, smaller pores, etc.), it can be beneficial if they are not constituted in a way that creates an unobstructed path for liquid to travel from one side of the anion exchange membrane to the other, for example. Likewise, in some embodiments, it can be beneficial if the anion exchange membrane is such that the image of the top of the membrane appears smooth and uniform. In some embodiments, it is beneficial if the membrane has a relatively low surface excess of silica-based ceramic. The surface excess of silica-based ceramic in the anion exchange membrane can be determined by SEM examination of the silica-based ceramic regions on the top or bottom surface of the porous support membrane. In some embodiments, the surface excess of silica-based ceramic on the top of the porous support membrane is less than or equal to 200 pm, less than or equal to 20 pm, less than or equal to 2 pm, or less as determined by SEM.

[0194] In some embodiments, greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 90%, greater than or equal to 95%, greater than or equal to 96%, greater than or equal to 97%, greater than or equal to 98%, greater than or equal to 99%, greater than or equal to 99.9%, and / or up to 100% of the pore volume of the porous support membrane is filled with the silica-based ceramic. In some embodiments, less than or equal to 100%, less than or equal to 99.9%, less than or equal to 99%, less than or equal to 98%, less than or equal to 97%, less than or equal to 96%, less than or equal to 95%, less than or equal to 90%, less than or equal to 80%, less than or equal to 75%, less than or equal to 70%, or less than or equal to 60% of the pore volume of the porous support membrane is filled with the silica-based ceramic. Combinations of these ranges are possible. For example, in some embodiments, greater than or equal to 50% and less than or equal to 100%, greater than or equal to 75% and less than or equal to 100%, greater than or equal to 90% and less than or equal to 100%, or greater than or equal to 97% and less than or equal to 100% of the pore volume of the porous support membrane is filled with the silica-based ceramic, as determined by SEM. For example, a representative number of cross-sections (e.g., at least three cross-sections) of SEM images of different regions of a film sample can be taken. Image processing software (e.g., ImageJ) can then be used to highlight the contrast between the void regions (typically shown as black in the image) and the filled regions (typically shown as gray in the image), and divide the area of the void regions by the total area probed. As long as a sufficiently large sample size (approximately 0.5 cm 2 ), the total “void area” relative to the total area of the cross-section can be determined. It can be important to take cross-sections from multiple regions of the film in an attempt to obtain a representative sample.

[0195] The anion exchange membrane can have any suitable thickness. For example, with reference to Figure 1AThe anion exchange membrane 100 has a thickness 154. The thickness of the anion exchange membrane can be selected based on, for example, the intended application of the anion exchange membrane or the geometry of a device (e.g., an electrochemical device, a filtration device, etc.) into which the anion exchange membrane is to be incorporated. In some embodiments, the thickness of the anion exchange membrane is greater than or equal to 1 pm, greater than or equal to 3 pm, greater than or equal to 5 pm, greater than or equal to 10 pm, greater than or equal to 25 pm, greater than or equal to 50 pm, greater than or equal to 100 pm, greater than or equal to 200 pm, greater than or equal to 300 pm, greater than or equal to 400 pm, greater than or equal to 500 pm, greater than or equal to 700 pm, greater than or equal to 1,000 pm, greater than or equal to 1,200 pm, or greater. In some embodiments, the thickness of the anion exchange membrane is less than or equal to 1,500 pm, less than or equal to 1,000 pm, less than or equal to 500 pm, less than or equal to 300 pm, less than or equal to 100 pm, less than or equal to 75 pm, less than or equal to 50 pm, or less. Combinations of these ranges are possible. For example, in some embodiments, the cross-sectional thickness of the porous support membrane is greater than or equal to 1 pm and less than or equal to 1,500 pm, or greater than or equal to 25 pm and less than or equal to 300 pm. The thickness of the porous support membrane in the anion exchange membrane can be determined by taking a SEM cross-section of the anion exchange membrane or by using calipers.

[0196] In some embodiments, the weight ratio of the silica-based ceramic to the porous support membrane in the anion exchange membrane is greater than or equal to 1 : 10, greater than or equal to 1 : 5, greater than or equal to 1 : 2, greater than or equal to 1 : 1, greater than or equal to 2: 1, greater than or equal to 5: 1, greater than or equal to 10: 1, greater than or equal to 20: 1, greater than or equal to 35: 1, greater than or equal to 50: 1, greater than or equal to 75: 1, greater than or equal to 100: 1, or greater. In some embodiments, the weight ratio of the silica-based ceramic to the porous support membrane in the anion exchange membrane is less than or equal to 300: 1, less than or equal to 250: 1, less than or equal to 220: 1, less than or equal to 200: 1, less than or equal to 150: 1, less than or equal to 120: 1, less than or equal to 100: 1, less than or equal to 75: 1, less than or equal to 50: 1, less than or equal to 35: 1, less than or equal to 20: 1, less than or equal to 10: 1, less than or equal to 5: 1, less than or equal to 2: 1, less than or equal to 1: 1, less than or equal to 1: 2, less than or equal to 1: 5, or less. Combinations of these ranges are possible. For example, in some embodiments, the weight ratio of the silica-based ceramic to the porous support membrane in the anion exchange membrane is greater than or equal to 1 : 10 and less than or equal to 300: 1, or greater than or equal to 1 : 2 and less than or equal to 220: 1.

[0197] In some embodiments, the density of the anion exchange membrane is greater than or equal to 0.8 g / cm 3 , greater than or equal to 0.9 g / cm 3 , greater than or equal to 1.0 g / cm 3 , greater than or equal to 1.2 g / cm 3 , greater than or equal to 1.5 g / cm 3 , greater than or equal to 1.8 g / cm 3 , or greater. In some embodiments, the density of the anion exchange membrane is less than or equal to 2.2 g / cm 3 , less than or equal to 2.1 g / cm 3 , less than or equal to 2.0 g / cm 3 , less than or equal to 1.9 g / cm 3 , less than or equal to 1.8 g / cm 3 , less than or equal to 1.7 g / cm 3 , less than or equal to 1.6 g / cm 3 , less than or equal to 1.5 g / cm 3 , less than or equal to 1.2 g / cm 3 , or less. Combinations of these ranges are possible. For example, in some embodiments, the density of the anion exchange membrane is greater than or equal to 0.8 g / cm 3 and less than or equal to 2.2 g / cm 3 , or greater than or equal to 1.0 g / cm 3 and less than or equal to 2.0 g / cm 3 .

[0198] In some embodiments, the basis weight of the anion exchange membrane is greater than or equal to 320 g / m 2 , greater than or equal to 350 g / m 2 , greater than or equal to 400 g / m 2 , greater than or equal to 450 g / m 2 , greater than or equal to 500 g / m 2 , greater than or equal to 550 g / m 2 , greater than or equal to 600 g / m 2 , or greater. In some embodiments, the basis weight of the anion exchange membrane is less than or equal to 880 g / m 2 , less than or equal to 850 g / m 2 , less than or equal to 800 g / m 2 , less than or equal to 750 g / m 2 , less than or equal to 700 g / m 2 , less than or equal to 650 g / m 2 , less than or equal to 600 g / m 2less than or equal to 550 g / m 2 less than or equal to 500 g / m 2 or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a basis weight of greater than or equal to 320 g / m 2 and less than or equal to 800 g / m 2 . The basis weight can be measured, for example, by cutting a 0.1 m 2 portion of the anion exchange membrane into 10 samples and measuring the weight of each sample after drying at 80 °C in a 0% humidity chamber for 24 hours.

[0199] In some embodiments, the anion exchange membrane has a specific surface area of greater than or equal to 50 m 2 / g, greater than or equal to 75 m 2 / g, greater than or equal to 100 m 2 / g, greater than or equal to 150 m 2 / g, greater than or equal to 200 m 2 / g, greater than or equal to 300 m 2 / g, greater than or equal to 400 m 2 / g, greater than or equal to 500 m 2 / g, or greater. In some embodiments, the anion exchange membrane has a specific surface area of less than or equal to 1,000 m 2 / g, less than or equal to 900 m 2 / g, less than or equal to 800 m 2 / g, less than or equal to 750 m 2 / g, less than or equal to 700 m 2 / g, less than or equal to 650 m 2 / g, less than or equal to 600 m 2 / g, less than or equal to 550 g / m 2 / g, less than or equal to 500 m 2 / g, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a specific surface area of greater than or equal to 500 g / m 2 and less than or equal to 1,000 g / m 2 .

[0200] In some embodiments, the anion exchange membrane comprises a compressible edge seal material. In some cases, such a compressible edge seal can act as a frame that can seal the membrane. In some cases where the anion exchange membrane is incorporated into an electrochemical device (e.g., a battery, a fuel cell, etc.), it can be useful to have a compressible edge seal material that can act as a frame. In some cases, the compressible edge seal material is mechanically compressible. In some embodiments, the compressible edge seal material is heat resistant and / or resistant to harsh chemical environments.Figure 5 An exemplary illustration of a non-limiting embodiment in which the anion exchange membrane 100 comprises an optional compressible edge seal material 180 is depicted.

[0201] In some embodiments, the anion exchange membrane comprises a compressible edge seal material along at least a portion of an edge of the anion exchange membrane. In some embodiments, the compressible edge seal material penetrates the porous support membrane by at least 1 pm. For example, again referring to Figure 5 , according to some embodiments, in some embodiments, the anion exchange membrane 100 comprises a silica-containing ceramic 150, a compressible edge seal material 180, and a porous support membrane 130 occluded behind the silica-based ceramic 130 and the compressible edge seal material 180. In some such cases, the compressible edge seal material 180 penetrates the porous support membrane 130 by at least 1 pm. In some embodiments, a compressible edge seal is positioned along all edges of the anion exchange membrane, defining a frame (e.g., as shown in Figure 5 In some embodiments, the compressible edge seal material covers about 50% or less, 25% or less, 10% or less, or 5% or less of the surface of the anion exchange membrane. In some embodiments, the percentage of the outer geometric surface area of the anion exchange membrane that is not covered by the compressible edge seal material is greater than or equal to 50%, greater than or equal to 90%, greater than or equal to 95%, or greater. In some embodiments, the percentage of the outer geometric surface area of the anion exchange membrane that is not covered by the compressible edge seal material is greater than or equal to 1 cm 2 , greater than or equal to 10 cm 2 , greater than or equal to 100 cm 2 , greater than or equal to 1,000 cm 2 , and / or up to 1 m 2 , up to 2 m 2 , up to 5 m 2 , up to 10 m 2 , or greater. The compressible edge seal material can have a width. For example, Figure 5 The compressible edge seal material 180 in FIG. 1 1 has a width 182. In some embodiments, the width of the compressible edge seal material is 1 mm or greater. In some embodiments, the width of the compressible edge seal material is 5 mm or greater. In some embodiments, the width of the edge portion is 1 cm or greater.

[0202] Any suitable method can be used to form the compressible edge seal material on the anion exchange membrane. For example, in some embodiments, the compressible edge seal material is formed on the porous support membrane prior to forming the silica-based ceramic coating on and / or within the porous support membrane. In some cases, the compressible edge seal material is formed on the porous support membrane after forming the silica-based ceramic coating on and / or within the porous support membrane.

[0203] In some embodiments, forming the compressible edge seal material includes a step of impregnating the edge portions of the porous support membrane with a polymeric material, e.g., impregnating the porous support membrane with a compressible polymer at one or more or all edges or in a region near one or more or all edges sufficient to form a frame that bounds the porous membrane support membrane (and ultimately the anion exchange membrane). In some embodiments, the compressible edge seal material is formed using ultrasonic welding, heat pressing, or UV curing. In some embodiments, impregnating the edge portions of the porous support membrane with a compressible polymer includes one or more techniques selected from melting, solution deposition, or in situ reaction.

[0204] In some embodiments, the compressible edge seal material comprises a polymeric material. In some embodiments, the polymeric material comprises an elastomeric polymer, e.g., a thermoplastic elastomeric polymer. Any suitable elastomeric polymer can be used to form the compressible edge seal material of the anion exchange membranes disclosed herein. Exemplary polymeric materials that the compressible edge seal material can comprise include, but are not limited to, silicone, epoxy, polyurethane, acrylic, silicone rubber, poly(styrene-isoprene-styrene), poly(styrene-isobutylene-styrene), polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyether ether ketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, or combinations or derivatives thereof.

[0205] As noted above, in some cases, the inventive features related to the anion exchange membranes and materials described herein can contribute to any of a number of potentially advantageous performance characteristics.

[0206] In some embodiments, the anion exchange membrane or anion exchange material (e.g., anion exchange membrane 100) has a relatively high anion exchange capacity. Having a relatively high anion exchange capacity is generally associated with good performance characteristics of the anion exchange material. The anion exchange capacity of a material such as a membrane can be measured using the following procedure. An anion exchange membrane is soaked in an aqueous sodium chloride solution (2.0 M) for at least 12 hours, during which time the sodium chloride solution is replaced with fresh sodium chloride solution twice. After soaking in the sodium chloride solution, the membrane is soaked in deionized water for at least 15 minutes, during which time the deionized water is replaced with fresh deionized water twice. After soaking in the deionized water, the membrane is soaked in an aqueous solution containing 1.0 M sodium nitrate for at least 3 hours, during which time the 1.0 M sodium nitrate solution is replaced with fresh 1.0 M sodium nitrate solution (1.0 M sodium nitrate in additional deionized water) twice. The anion exchange membrane is removed from the sodium nitrate solution and rinsed with deionized water. All of the sodium nitrate solution and the rinse solution are then combined and titrated with an aqueous solution containing 0.010 M silver nitrate using potassium chromate (0.25 M in solution) as an indicator. The titration is ended when the solution color changes from bright yellow to light yellow brown. The titration can be performed using an automated titrator without the use of an indicator such as potassium chromate, but instead using, for example, a silver sensing probe. A set of “blank” sodium nitrate solutions that are not exposed to an anion exchange membrane are used and titrated to determine the baseline chloride background of the aqueous solution. The membrane is rinsed with deionized water and dried in an oven overnight. The weight of the membrane is recorded after the drying step. The anion exchange capacity (AEC) is measured using:

[0207]

[0208] where V 滴定剂 is the volume of silver nitrate titrant added during the titration corrected for the baseline chloride concentration of the aqueous solution (V 滴定剂 = V 滴定剂，膜 -V 滴定剂，空白 ), C 滴定剂 is the concentration of the titrant (0.010 M in this case), and w 干燥 is the weight of the dried membrane in grams. In the present disclosure, the anion exchange capacity is reported in eq / g, which is equivalent (eq) per unit weight (g, gram). The number of equivalents in a solution refers to the number of moles of an ion (e.g., chloride) in the solution multiplied by the valence of the ion. The above-described procedure can be used for any anion exchange material, not just membranes.

[0209] In some embodiments, it has been observed that the anion exchange membranes described herein having certain functional groups (e.g., quaternary ammonium groups) at relatively high loadings can at least in part contribute to relatively high anion exchange capacities as compared to certain existing anion exchange membranes. Further, it has been observed that the anion exchange capacities of the anion exchange membranes and materials described herein can also at least in part depend on the composition of the silicon-containing precursor sols from which the silica-based ceramic of the anion exchange membranes is derived (e.g., the water to silicon ratio, the acid strength, the ratio of silicon-containing precursors such as TEOS and TMAPS).

[0210] In some embodiments, the anion exchange membrane or anion exchange material has an anion exchange capacity greater than or equal to 0.01 milliequivalents per gram (meq / g). In some embodiments, the anion exchange membrane or anion exchange material has an anion exchange capacity greater than or equal to 0.1 meq / g, greater than or equal to 0.2 meq / g, greater than or equal to 0.3 meq / g, greater than or equal to 0.5 meq / g, greater than or equal to 0.7 meq / g, greater than or equal to 1 meq / g, greater than or equal to 1.2 meq / g, greater than or equal to 1.5 meq / g, greater than or equal to 1.7 meq / g, or greater. In some embodiments, the anion exchange membrane or anion exchange material has an anion exchange capacity less than or equal to 2.5 meq / g, less than or equal to 2.2 meq / g, 2 meq / g, less than or equal to 1.8 meq / g, less than or equal to 1.5 meq / g, less than or equal to 1.2 meq / g, less than or equal to 1 meq / g, less than or equal to 0.7 meq / g, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane or anion exchange material has an anion exchange capacity greater than or equal to 0.01 meq / g and less than or equal to 2.5 meq / g, greater than or equal to 0.1 meq / g and less than or equal to 2.5 meq / g, greater than or equal to 0.5 meq / g and less than or equal to 2.5 meq / g, or greater than or equal to 1 meq / g and less than or equal to 2.5 meq / g. In some embodiments, the anion exchange membrane or anion exchange material has a relatively high anion exchange capacity while there is a relatively large amount of Si present in the silica-based ceramic of the anion exchange membrane. For example, in some embodiments, the anion exchange membrane has an anion exchange capacity greater than or equal to 0.01 meq / g, greater than or equal to 0.1 meq / g, greater than or equal to 0.2 meq / g, greater than or equal to 0.3 meq / g, greater than or equal to 0.5 meq / g, greater than or equal to 0.7 meq / g, greater than or equal to 1 meq / g, and / or up to 1.2 meq / g, up to 1.5 meq / g, up to 1.8 meq / g, or up to 2 meq / g, while there is Si present in an amount of at least 6 wt%, at least 10 wt%, at least 12 wt%, at least 15 wt%, at least 17 wt%, at least 20 wt%, and / or up to 24 wt%, up to 26 wt%, up to 28 wt%, up to 30 wt%, up to 40 wt%, up to 47 wt%, up to 60 wt%, or greater, in the silica-based ceramic.

[0211] In some embodiments, the anion exchange membrane or anion exchange material experiences a relatively low amount of dimensional swelling (in the form of linear swelling) according to the dimensional swelling test described herein. As described above, in some cases, having a relatively low amount of dimensional swelling can be advantageous for an anion exchange membrane or anion exchange material. It has been observed that the anion exchange membranes and materials described herein, some of which include silica-based ceramics, can experience a relatively low amount of dimensional swelling (e.g., linear swelling) as compared to certain existing anion exchange membranes or anion exchange materials (e.g., those that primarily include polymeric components such as hydrocarbon or fluorocarbon polymers). Without wishing to be bound by any particular theory, it is believed that linear swelling can occur when the pore size or structure of a membrane changes (e.g., swells, deswells) based on the environment of the anion exchange membrane (e.g., temperature, humidity, salinity). When an anion exchange membrane is incorporated into a device in which the edges of the membrane are fixed in place, such as an electrochemical device (e.g., an electrochemical stack), swelling / deswelling can create mechanical stresses that can cause the membrane to fail. Having a relatively low linear swelling can also make it easier to align the membrane (e.g., via making alignment holes in the membrane) when positioning the membrane in a device (e.g., stack) during assembly. However, in some embodiments, it is beneficial to have some amount of linear swelling (e.g., via swelling) to achieve permeation of the hydration domain and beneficial performance characteristics (e.g., anion exchange capacity, chloride ion conductivity). Linear swelling of an anion exchange membrane can be measured using the following dimensional swelling test. The dimensional swelling test is performed using a modified version of ASTM D756 and ASTM D570. A membrane sample is cut into a 50 mm x 50 mm square and conditioned in a space held at 23 °C and 50% relative humidity for 48 hours. After conditioning, the length and width of the membrane sample are measured. The sample is then soaked in 23 °C water or 100 °C water for one hour. After soaking, the membrane is removed from the water and wiped with a dry cloth. The length of each side is recorded immediately after the membrane is wiped with the cloth. Linear swelling for a given dimension (e.g., length or width) is determined by dividing the length measured for that dimension after the step of wiping the membrane with a dry cloth by the original 50 mm length, and is reported as a percent change relative to the original 50 mm length. For example, a membrane that measures 55 mm after soaking and wiping with a cloth has a linear swelling of 10%, while a membrane that measures 60 mm after soaking and wiping with a cloth has a linear swelling of 20%. Linear swelling of an anion exchange membrane is determined by performing the dimensional swelling test described above on three identical samples and determining the number average of the three tests.

[0212] In some embodiments, as described above, the anion exchange membrane has a relatively small linear expansion. In some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of less than or equal to 10%, less than or equal to 8%, less than or equal to 6%, less than or equal to 5%, less than or equal to 2%, less than or equal to 1%, less than or equal to 0.5%, or less. In some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of as low as 0%. In some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of greater than or equal to 0%, greater than or equal to 0.01%, or greater than or equal to 0.1%. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of greater than or equal to 0% and less than or equal to 5%, greater than or equal to 0% and less than or equal to 2%, greater than or equal to 0% and less than or equal to 1%, or greater than or equal to 0% and less than or equal to 0.5%.

[0213] In some embodiments, the anion exchange membrane has a relatively small linear expansion while having a relatively large anion exchange capacity. For example, in some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of less than or equal to 20%, less than or equal to 15%, less than or equal to 10%, less than or equal to 8%, less than or equal to 6%, less than or equal to 5%, less than or equal to 2%, less than or equal to 1%, less than or equal to 0.5%, or less, while having an anion exchange capacity of greater than or equal to 0.01 meq / g, greater than or equal to 0.2 meq / g, greater than or equal to 0.3 meq / g, greater than or equal to 0.5 meq / g, greater than or equal to 0.7 meq / g, greater than or equal to 1 meq / g, and / or as high as 1.2 meq / g, as high as 1.5 meq / g, as high as 1.8 meq / g, as high as 2 meq / g, as high as 2.5 meq / g, or more. With certain existing anion exchange membranes or anion exchange materials, it can not be possible to obtain such a high anion exchange capacity while experiencing such a small amount of dimensional expansion (e.g., linear expansion) upon exposure to water.

[0214] In some embodiments, the anion exchange membrane or anion exchange material has a relatively high anion permselectivity. Anion permselectivity generally refers to a measure that quantifies the degree to which a membrane or material is more permeable to anions than to cations. In certain applications, selectivity for anions over cations can be an important characteristic of an anion exchange membrane. In this context, anion permselectivity is measured by comparing the permeability of the membrane or material for chloride anions versus sodium anions. In this case, selectivity is measured using open circuit voltage method. The open circuit voltage method is well known in the literature, which is described, for example, in Sata, T., Properties, Characterization and Microstructure of Ion Exchange Membranes. In Ion Exchange Membranes: Preparation, Characterization, Modification and Application, Sata, T., Ed. The Royal Society of Chemistry: 2004; pp. 89-134, and in Kingsbury, R. S.; Flotron, S.; Zhu, S.; Call, D. F.; Coronell, O., Junction Potentials Bias Measurements of Ion Exchange Membrane Permselectivity. Environmental Science & Technology 2018, 52 (8), 4929-4936, both of which are incorporated herein by reference in their entirety. In the performance of the open circuit voltage method test, the membrane is equilibrated in 0.5 M NaCl aqueous solution prior to testing. The membrane is then mounted in a two-compartment cell. One compartment of the cell is filled with 100 mL of 0.5 M NaCl aqueous solution, while the other compartment is filled with 100 mL of 0.1 M NaCl aqueous solution. Each compartment of the two-compartment cell is stirred, and fresh solution is pumped into each compartment at a rate of about 5 mL / minute. Voltage measurements are made using AgCl filament electrodes and a multimeter (e.g., Fluke 116 True RMS). The AgCl filament electrodes are immersed in each compartment, and the multimeter is set to the dc voltage setting. The multimeter probes are connected to each AgCl wire, and voltage readings are taken from the multimeter. The wires are allowed to equilibrate for 30 minutes prior to recording the final membrane potential. The anion permselectivity is then calculated using the Nernst equation. The shift potential of the AgCl wires is measured in 0.5 M NaCl and 0.1 M NaCl solutions, and the average is taken to represent the reference potential in the final calculation.

[0215] In some embodiments, the anion exchange membrane or anion exchange material has an anion selectivity greater than or equal to 65%. In some embodiments, the anion exchange membrane has an anion selectivity greater than or equal to 70%, greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, greater than or equal to 95%, greater than or equal to 97%, greater than or equal to 98%, or greater. In some embodiments, the anion exchange membrane has an anion selectivity less than or equal to 100%, less than or equal to 99%, less than or equal to 98%, less than or equal to 97%, less than or equal to 95%, less than or equal to 90%, less than or equal to 85%, less than or equal to 80%, or less. Combinations of the above are possible. For example, in some embodiments, the anion exchange membrane has an anion selectivity greater than or equal to 65% and less than or equal to 100%, greater than or equal to 85% and less than or equal to 100%, greater than or equal to 90% and less than or equal to 100%, greater than or equal to 95% and less than or equal to 100%, or greater than or equal to 98% and less than or equal to 100%.

[0216] In some embodiments, the anion exchange membrane has a relatively high chloride (Cl - ) conductivity (C C1). Chloride ion conductivity can be a useful measure to evaluate the conductivity of an anion exchange membrane with respect to anions (e.g., chloride ions). Having a relatively high chloride ion conductivity can be important in certain applications, such as certain electrochemical applications (e.g., electrodialysis applications). For example, in some embodiments, a relatively high chloride ion conductivity can facilitate energy efficiency in an electrochemical system. It has been observed that the anion exchange membranes described herein can have a relatively high chloride ion conductivity, at least in part due to the inventive features of the anion exchange membranes, such as a relatively high loading of functional groups (e.g., quaternary ammonium groups). Chloride ion conductivity can also be influenced by the pore structure (e.g., pore size, pore-pore distance, pore ordering such as fractal aggregation, among others) of the silica-based ceramic. It has been observed herein that ion conductivity is not necessarily related to other properties of an ion exchange membrane or material (e.g., anion exchange capacity), and the structural and compositional factors that lead to a relatively high chloride ion conductivity can be different from those that influence other properties. For example, if an anion exchange membrane includes functional groups (e.g., quaternary ammonium groups) located near the outer surface of the anion exchange membrane, the membrane can have a relatively high anion exchange capacity but poor chloride ion conductivity, as the functional groups will not be distributed throughout the thickness of the membrane. In contrast, an anion exchange membrane with functional groups that are effectively distributed (e.g., substantially uniformly distributed) can have both a relatively high anion exchange capacity and a relatively high chloride ion conductivity. Factors that influence such distribution can include the selection of precursor materials (e.g., silicon-containing precursor materials), the ratio of precursor materials (e.g., in a silicon-containing precursor sol), and the selection of a porous support membrane (if present).

[0217] As another example, certain existing anion exchange compositions with a relatively high amount of functional groups (e.g., quaternary ammonium groups) tend to typically experience a greater linear swelling due to the functional groups' tendency to adsorb water, resulting in swelling. It has been recognized herein that an anion exchange membrane with a relatively high chloride ion conductivity and a relatively low linear swelling can be achieved. One way to achieve such a result is by designing the pore structure of the silica-based ceramic such that the membrane swells upon hydration enough to achieve permeable pores, but not so much that the pores become too large and lack selective permeability while producing a significant linear swelling. In some embodiments, the permeable pores resulting from some swelling of the membrane can facilitate both a relatively high chloride ion conductivity and a relatively high anion exchange capacity.

[0218] Chloride ion conductivity of anion exchange membranes can be measured using the following four-electrode electrical impedance spectroscopy (EIS) procedure. The four-electrode electrical impedance spectroscopy procedure is described in more detail in Galama, A. H.; Hoog, N. A.; Yntema, D. R., Method for determining ion exchange membrane resistance for electrodialysis systems. Desalination 2016, 380, 1-11, which is incorporated herein by reference in its entirety. The membranes are equilibrated in 0.5 M NaCl solution prior to testing. The membranes are then incorporated into a two-compartment cell. Prior to incorporating the membranes into the two-compartment cell, the two-compartment cell is first assembled and filled with 0.5 M NaCl solution to measure the background resistance of the cell. The cell is then emptied, reassembled with the membranes, and filled with 0.5 NaCl solution, at which time another resistance measurement is taken. A constant current EIS measurement is used. A constant current of 5 mA is applied to the working platinum electrode, and scanned from 10,000 Hz to 10 Hz while measuring 15 points per decade. The resulting transmembrane voltage is measured using an Ag / AgCl reference electrode. The resistance of the blank cell and the cell with the membranes incorporated is taken from the x-axis intercept of the resulting Nyquist plot (representing the real part of the impedance), and the difference corresponds to the resistance of the membrane. The conductance is determined by taking the inverse of the resistance, and normalized to the membrane surface area and thickness to determine the chloride ion conductivity.

[0219] In some embodiments, the anion exchange membrane or anion exchange material has a chloride ion conductivity greater than or equal to 0.00001 S / cm. In some embodiments, the anion exchange membrane or anion exchange material has a chloride ion conductivity greater than or equal to 0.00005 S / cm, greater than or equal to 0.0001 S / cm, greater than or equal to 0.0005 S / cm, greater than or equal to 0.001 S / cm, greater than or equal to 0.005 S / cm, greater than or equal to 0.01 S / cm, or greater. In some embodiments, the anion exchange membrane or anion exchange material has a chloride ion conductivity less than or equal to 0.3 S / cm, less than or equal to 0.2 S / cm, less than or equal to 0.1 S / cm, less than or equal to 0.05 S / cm, less than or equal to 0.02 S / cm, less than or equal to 0.01 S / cm, less than or equal to 0.005 S / cm, less than or equal to 0.001 S / cm, less than or equal to 0.0005 S / cm, or less. Combinations of the above ranges are possible. For example, in some embodiments, the anion exchange membrane or anion exchange material has a chloride ion conductivity greater than or equal to 0.00001 S / cm and less than or equal to 0.3 S / cm, greater than or equal to 0.001 S / cm and less than or equal to 0.3 S / cm, or greater than or equal to 0.01 S / cm and less than or equal to 0.3 S / cm.

[0220] In some embodiments, the anion exchange membrane or anion exchange material has a relatively high chloride ion conductivity and a relatively high anion exchange capacity. For example, in some embodiments, the anion exchange membrane has a chloride ion conductivity greater than or equal to 0.00001 S / cm, greater than or equal to 0.00005 S / cm, greater than or equal to 0.0001 S / cm, greater than or equal to 0.0005 S / cm, greater than or equal to 0.001 S / cm, greater than or equal to 0.005 S / cm, greater than or equal to 0.01 S / cm, and / or up to 0.02 S / cm, up to 0.05 S / cm, up to 0.1 S / cm, up to 0.2 S / cm, or up to 0.3 S / cm, while having an anion exchange capacity greater than or equal to 0.01 meq / g, greater than or equal to 0.1 meq / g, greater than or equal to 0.2 meq / g, greater than or equal to 0.3 meq / g, greater than or equal to 0.5 meq / g, greater than or equal to 0.7 meq / g, greater than or equal to 1 meq / g, and / or up to 1.2 meq / g, up to 1.5 meq / g, up to 1.8 meq / g, or up to 2 meq / g. Combinations of the above ranges as well as other ranges of chloride ion conductivity and / or anion exchange capacity described elsewhere herein are also possible.

[0221] In some embodiments, the anion exchange membrane or anion exchange material has a relatively high chloride ion conductivity and a relatively low linear expansion. For example, in some embodiments, the anion exchange membrane has a chloride ion conductivity greater than or equal to 0.00001 S / cm, greater than or equal to 0.00005 S / cm, greater than or equal to 0.0001 S / cm, greater than or equal to 0.0005 S / cm, greater than or equal to 0.001 S / cm, greater than or equal to 0.005 S / cm, greater than or equal to 0.01 S / cm, and / or up to 0.02 S / cm, up to 0.05 S / cm, up to 0.1 S / cm, up to 0.2 S / cm, or up to 0.3 S / cm, while having a linear expansion less than or equal to 10%, less than or equal to 8%, less than or equal to 6%, less than or equal to 5%, less than or equal to 2%, less than or equal to 1%, less than or equal to 0.5%, or less. Combinations of the above-mentioned ranges, as well as other ranges of chloride ion conductivity and / or linear expansion described elsewhere herein, are also possible.

[0222] In some embodiments, the anion exchange membranes have a relatively low osmotic water permeance. Osmotic water permeance of a membrane generally refers to the flux of water across the membrane due to osmotic pressure. Having a relatively low osmotic water permeance can be beneficial in certain applications, for example, where the anion exchange membrane is used in an electrochemical application, such as an electrodialysis application. Details of an exemplary test for determining osmotic water permeance of a membrane are described by Kingsbury, Ryan; Zhu, Shan; Flotron, Sophie; Coronell, Orlando (2018): Microstructure determines water and salt permeation in commercial ion exchange membranes. ChemRxiv. Preprint and in Kingsbury, R. S., Zhu, S., Flotron, S., & Coronell, O. (2018). Microstructure determines water and salt permeation in commercial ion-exchange membranes. ACS applied materials & interfaces, 10(46), 39745-39756, each of which is incorporated herein by reference in its entirety. The osmotic water permeance of the membranes described herein can be determined using the following procedure. The membrane is incorporated into a two-compartment cell and the volumetric flow of water across the membrane is measured to determine the flux of water across the membrane due to osmotic pressure. Prior to testing, one compartment of the two-compartment cell is filled with a 4 M aqueous NaCl solution. To begin testing, the membrane is assembled into the two-compartment cell and one compartment of the two-compartment cell is filled with a 2 M to 4 M aqueous NaCl solution and the other compartment of the two-compartment cell is filled with deionized water. The membrane is exposed to the concentration gradient between the 2 M to 4 M NaCl solution and the deionized water solution in their respective compartments for at least one hour prior to recording any volume changes to establish pseudo-steady state for water transport through the membrane. The cell is then emptied and completely refilled with fresh 2 M to 4 M NaCl and deionized water. The cell is sealed with a cap equipped with a volumetric syringe with 0.01 mL increments and the level of the solutions in the cell is adjusted to be approximately equal at the start of the test. The two compartments of the two-compartment cell are agitated via stirring with a stir bar for the duration of the test. Once the levels are equal, a stopwatch is started and the volume is recorded as a function of time until a volume change of at least 0.05 mL is observed in each compartment.

[0223] Water permeance (A [L.m -2 . hour -1 . bar -1) and hydraulic flux of water across the membrane (J W [L. m -2 . hour -1 ]) is related by:

[0224]

[0225] where ΔΡ and Δπ [bar] are the difference in hydraulic pressure and osmotic pressure across the membrane, respectively. Flux J W can be calculated from the flow of water across the membrane (Q W [L. hour -1 ]) divided by the membrane area [m 2 ]:

[0226]

[0227] Flow can be determined by calculating the slope of the volume reading of each compartment over time and taking the average of the two sides (slopes should be similar in magnitude and opposite in sign). Since no external hydraulic pressure (ΔΡ = 0) is applied to the membrane during the test, the osmotic pressure is calculated using the Gibbs equation for non-ideality of the concentrated solution from the composition of the solutions.

[0228]

[0229] Water activity is calculated via the Pitzer activity model using the freely available pyEQL software.

[0230] In some embodiments, the anion exchange membrane has a permeate water flux of less than or equal to 100 mL / (hour-bar-m 2 ), less than or equal to 50 mL / (hour-bar-m 2 ). In some embodiments, the anion exchange membrane has a permeate water flux of less than or equal to 45 mL / (hour-bar-m 2 ), less than or equal to 40 mL / (hour-bar-m 2 ), less than or equal to 35 mL / (hour-bar-m 2 ), less than or equal to 30 mL / (hour-bar-m 2 ), less than or equal to 20 mL / (hour-bar-m 2 ), less than or equal to 15 mL / (hour-bar-m 2 ), less than or equal to 10 mL / (hour-bar-m 2 ), less than or equal to 5 mL / (hour-bar-m 2 ), less than or equal to 4 mL / (hour-bar-m 2 ), less than or equal to 3 mL / (hour-bar-m 2 ), less than or equal to 2.5 mL / (hour-bar-m 2), less than or equal to 2 mL / (hour·bar·m 2 ( ), or even less. In some embodiments, the permeate water permeability of the anion exchange membrane is greater than or equal to 0 mL / (h·bar·m 2 ), greater than or equal to 0.1 mL / (hour·bar·m 2 ), greater than or equal to 0.2 mL / (hour·bar·m 2 ), greater than or equal to 0.3 mL / (hour·bar·m 2 ), greater than or equal to 0.5 mL / (hour·bar·m 2 ), greater than or equal to 0.8 mL / (hour·bar·m 2 ), greater than or equal to 1 mL / (hour·bar·m 2 ), greater than or equal to 1.2 mL / (hour·bar·m 2 ), greater than or equal to 1.5 mL / (hour·bar·m 2 ), greater than or equal to 2 mL / (hour·bar·m 2 ), greater than or equal to 5 mL / (hour·bar·m 2 ( ), or even greater. Combinations of these ranges are possible. For example, in some embodiments, the permeate water permeability of the anion exchange membrane is greater than or equal to 0 mL / (h·bar·m 2 And less than or equal to 100 mL / (hour·bar·m) 2 ), greater than or equal to 0 mL / (hour·bar·m 2 And less than or equal to 50 mL / (hour·bar·m) 2 ), greater than or equal to 0 mL / (hour·bar·m 2 And less than or equal to 10 mL / (hour·bar·m) 2 ), greater than or equal to 0 mL / (hour·bar·m 2 And less than or equal to 5 mL / (hour·bar·m) 2 ), or greater than or equal to 0 mL / (hour·bar·m 2 And less than or equal to 2 mL / (hour·bar·m) 2 ).

[0231] In some embodiments, the anion exchange membranes have a relatively large water uptake. As used herein, the water uptake of a membrane refers to the amount of water that the membrane can take up when immersed in water at 100 °C. The water uptake of a membrane can be measured using the following procedure. The membrane is cut into 50 mm x 50 mm squares and dried in an oven set to a temperature greater than 105 °C for 24 hours. The weight of the membrane is measured after drying. The water uptake is then measured by immersing the membrane in boiling water at 100 °C for one hour. The membrane is then removed from the boiling water bath and wiped dry with a dry cloth to remove surface water. The membrane is then weighed immediately after the step of wiping the membrane with the cloth. This procedure is performed on three identical membranes each, and the number average of the change in weight of the membranes after being immersed in boiling water is used to determine the water uptake of the membrane. It has been unexpectedly observed that, in some embodiments, the anion exchange membranes described herein (e.g., anion exchange membranes comprising a silica-based ceramic containing covalently bonded functional groups such as quaternary ammonium groups) are able to have a relatively high water uptake while experiencing a relatively small amount of dimensional expansion (e.g., linear expansion) as compared to certain prior anion exchange membranes. The water uptake can be expressed as a weight percent change relative to the weight of the dry membrane.

[0232] In some embodiments, the water uptake of the anion exchange membrane is greater than or equal to 1%, greater than or equal to 3%, greater than or equal to 5%, greater than or equal to 8%, greater than or equal to 10%, greater than or equal to 15%, greater than or equal to 20%, greater than or equal to 25%, greater than or equal to 30%, greater than or equal to 35%, greater than or equal to 40%, greater than or equal to 45%, greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, or greater. In some embodiments, the water uptake of the anion exchange membrane is less than or equal to 100%, less than or equal to 90%, less than or equal to 85%, less than or equal to 80%, less than or equal to 75%, less than or equal to 70%, less than or equal to 65%, less than or equal to 60%, less than or equal to 50%, less than or equal to 40%, less than or equal to 35%, less than or equal to 25%, less than or equal to 15%, less than or equal to 10%, or less. Combinations of these ranges are possible. For example, in some embodiments, the water uptake of the anion exchange membrane is greater than or equal to 1% and less than or equal to 100%, greater than or equal to 5% and less than or equal to 50%, or greater than or equal to 10% and less than or equal to 25%.

[0233] In some embodiments, the anion exchange membranes have a relatively high water uptake and a relatively low linear expansion. In some embodiments, the anion exchange membranes have a water uptake greater than or equal to 1%, greater than or equal to 3%, greater than or equal to 5%, greater than or equal to 8%, greater than or equal to 10%, greater than or equal to 15%, greater than or equal to 20%, greater than or equal to 25%, greater than or equal to 30%, greater than or equal to 35%, greater than or equal to 40%, greater than or equal to 45%, greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, while having a linear expansion less than or equal to 10%, less than or equal to 8%, less than or equal to 6%, less than or equal to 5%, less than or equal to 2%, less than or equal to 1%, less than or equal to 0.5%, or less. Combinations of the above-mentioned ranges, as well as other ranges of water uptake and / or linear expansion described elsewhere herein, are also possible.

[0234] In some embodiments, the anion exchange membranes have a relatively high mechanical rupture pressure. The mechanical rupture pressure of a membrane generally refers to the amount of force that can be applied to the membrane before the membrane experiences mechanical failure and rupture. In some cases, having a relatively high mechanical rupture pressure can be advantageous for an anion exchange membrane. For example, in certain applications involving a flowing solution in contact with the anion exchange membrane (e.g., a redox flow battery) or the application of static or hydraulic pressure to the anion exchange membrane (e.g., reverse osmosis or nanofiltration), having sufficient mechanical rupture pressure can be important in avoiding failure of the membrane during operation. It has been observed that, in some embodiments, the anion exchange membranes described herein can have good mechanical properties, such as high mechanical rupture pressure, while also having good performance properties (e.g., anion exchange capacity, anion permselectivity). In certain cases, this combination of good mechanical properties and good performance properties can be achieved by combining a silica-based ceramic, which can impart good anion exchange performance properties, with a porous support membrane, which can impart good mechanical properties.

[0235] The mechanical rupture pressure of an anion exchange membrane can be determined using the following procedure. This procedure can be used to determine the rupture pressure in units of Newtons (N). This procedure is based on a modified version of ASTM D6797. Prior to testing, a membrane having a circular shape with a diameter of 70 mm is kept hydrated in water. The membrane is removed from the water and excess water on the surface of the membrane is wiped off with a dry cloth. After the step of wiping the membrane with a dry cloth, the membrane is clamped in a fixture with a ring-shaped clamp having an inner diameter of 40 mm in the center of the membrane. A polished steel ball with a diameter of 25 mm is used to apply force to the membrane. The polished steel ball is attached to the movable portion of a constant rate of elongation tensile testing machine. The tensile testing machine is started by setting the rate of travel to 305 mm / minute, and the ball is allowed to travel until the membrane ruptures.

[0236] As described above, in some embodiments, the anion exchange membrane has a relatively high mechanical burst pressure as measured using the steps described above. In some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 1.5 N, at least 1.7 N, at least 2.0 N, at least 5 N, at least 10 N, at least 25 N, or more. In some embodiments, the anion exchange membrane has a mechanical burst pressure of less than or equal to 1,000 N, less than or equal to 900 N, less than or equal to 800 N, less than or equal to 700 N, less than or equal to 600 N, less than or equal to 500 N, less than or equal to 400 N, less than or equal to 250 N, less than or equal to 100 N, less than or equal to 75 N, less than or equal to 50 N, less than or equal to 25 N, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 1.5 N and less than or equal to 1,000 N, or greater than or equal to 1.7 N and less than or equal to 400 N.

[0237] The mechanical burst pressure of an anion exchange membrane can also be determined in units of pressure. Such units provide a measure that is independent of the dimensional properties of the anion exchange membrane (e.g., the area of the membrane). The mechanical burst pressure of an anion exchange membrane can be determined in units of pressure using the following procedure. This procedure is based on a modified version of ASTM D3786 using a Cyeeyo 302A QT Burst Tester. Prior to testing, a membrane having a circular shape with a diameter of 40 mm is kept hydrated in water. The membrane is removed from the water and excess water is blotted from the surface of the membrane with a dry cloth. After the step of blotting the membrane with a dry cloth, the membrane is clamped in a fixture having a ring-shaped clamp with an inner diameter of 33 mm in the center of the membrane. During the test, a diaphragm of the burst tester beneath the sample expands upward until the point of rupture of the test sample. The point of rupture, expressed as a peak pressure value, can be read from the display of the burst tester. The point of rupture corresponds to the mechanical burst pressure.

[0238] As described above, in some embodiments, the anion exchange membrane has a relatively high mechanical burst pressure as measured using the above-described procedure in units of pressure. In some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 2.0 pounds per square inch (PSI), at least 2.1 PSI, at least 2.5 PSI, at least 3.0 PSI, at least 3.5 PSI, at least 4.0 PSI, at least 5.0 PSI, at least 6.0 PSI, at least 8.0 PSI, at least 10.0 PSI, at least 12.0 PSI, at least 15.0 PSI, at least 20.0 PSI, at least 25.0 PSI, at least 30.0 PSI, at least 40.0 PSI, at least 50.0 PSI, at least 60.0 PSI, at least 75.0 PSI, at least 100.0 PSI, or more. In some embodiments, the anion exchange membrane has a mechanical burst pressure of less than or equal to 1,000 PSI, less than or equal to 900 PSI, less than or equal to 800 PSI, less than or equal to 700 PSI, less than or equal to 600 PSI, less than or equal to 500 PSI, less than or equal to 400 PSI, less than or equal to 250 PSI, less than or equal to 150 PSI, less than or equal to 100 PSI, less than or equal to 90 PSI, less than or equal to 80 PSI, less than or equal to 75 PSI, less than or equal to 70 PSI, less than or equal to 65 PSI, less than or equal to 60 PSI, less than or equal to 55 PSI, less than or equal to 50 PSI, less than or equal to 40 PSI, less than or equal to 30 PSI, less than or equal to 25 PSI, less than or equal to 10 PSI, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 2.0 PSI and less than or equal to 1,000 PSI, greater than or equal to 5.0 PSI and less than or equal to 400 PSI, or greater than or equal to 20 PSI and less than or equal to 60 PSI.

[0239] In certain aspects, methods of making an anion exchange membrane from the materials described herein are provided. One exemplary method of making an anion exchange membrane includes a sol-gel method.

[0240] Figure 6 is a flow chart illustrating one non-limiting method of making an anion exchange membrane. In some embodiments, a porous support membrane as described herein is provided. For example, Figure 6 A porous support membrane 130 is shown. In some cases, the optional step of applying a compressible edge seal material to the porous support membrane is performed. For example, as shown in step 1 of Figure 6 A compressible edge seal material 180 is formed on the porous support membrane 130, as shown in step 1 of

[0241] In non-limiting cases, the optional compressible edge material is formed at least in part by adding a polymer to the top surface of the porous support membrane such that the polymer infiltrates the entire thickness of the porous support membrane and forms a border of at least 1 pm in width around the edge region of the porous support membrane. In some cases, such a compressible edge material can act as a frame that can help seal the anion exchange membrane (e.g., in a cell). The method of forming the compressible edge material depends on the composition (e.g., polymeric material) used to form the compressible edge material. In some cases, the compressible edge material can be applied as a film and / or sheet using heat, solvent, or radiation. In some embodiments, the optional compressible edge material can be applied from a liquid phase as a solution or dispersion to the porous support membrane using any of a variety of known coating techniques (e.g., dip coating, spray coating, drop coating, knife coating, screen coating, etc.). In some embodiments, the method of forming the compressible edge material can include a step of in situ reaction after deposition of the precursor material. For example, in some cases, an in situ reaction occurs in which deposited monomeric units react to form a polymer within the porous support membrane. In some embodiments, the percentage of the external geometric surface area of the porous support membrane that is not covered by the compressible edge material is greater than or equal to 30%, greater than or equal to 40%, greater than or equal to 50%, greater than or equal to 70%, greater than or equal to 80%, greater than or equal to 90%, greater than or equal to 95%, greater than or equal to 99%, or greater. In some embodiments, the area of the external geometric surface area of the porous support membrane that is not covered by the compressible edge material is greater than or equal to 1 cm 2 , greater than or equal to 10 cm 2 , greater than or equal to 100 cm 2 , greater than or equal to 1,000 cm 2 , and / or up to 1 m 2 , up to 2 m 2 , up to 5 m 2 , 10 m 2 , or greater.

[0242] In some embodiments, a silicon-containing precursor sol is applied to the porous support membrane during the manufacture of the anion exchange membrane. For example, again referring to Figure 6In step 2, a silicon-containing precursor sol is applied to the porous support membrane 130 (optionally including compressibility material 180) via solution 270. Exemplary compositions of the silicon-containing precursor sol are described herein. In some embodiments, the silicon-containing precursor sol is applied to the porous support membrane such that the silicon-containing precursor sol wicks into the porous support membrane and coats at least a portion of the porous support membrane. In some embodiments, the sol wicks into the interior of the porous support membrane and in some cases fills some or all of the porous volume of the porous support membrane. According to some embodiments, the silicon-containing precursor sol (e.g., solution 270) can be applied to the porous support membrane using one or more standard coating processes such as dip coating, spray coating, roll coating, doctor blade coating, screen printing, or blowing with air (e.g., with an air knife). Excess silicon-containing precursor sol can be removed via any suitable method such as scraping. During the step of applying the silicon-containing precursor sol to the porous support membrane, the porous support membrane can be in any of a variety of orientations (e.g., vertical, horizontal). In some embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when the porous support membrane is flat and self-supporting. In some embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when the porous support membrane is flat and in contact with another surface. In some embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when the porous support membrane is curved and self-supporting. In some embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when the porous support membrane is curved and in contact with another surface. As one example, in some cases, the porous support membrane can be arranged in a cylindrical or conical shape during application of the silicon-containing precursor sol (e.g., solution 270) in step 2. In some embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when the membrane is held taut in at least one dimension. Figure 6

[0243] In some embodiments, prior to and / or during the step of applying the silicon-containing precursor sol to the porous support membrane, the silicon-containing precursor sol is a single-phase sol. For example, in embodiments in which the silicon-containing precursor sol includes two or more different types of silicon-based precursors (e.g., both a silane including a functional group such as a quaternary ammonium group and a silane not including such a functional group), the silicon-containing precursor sol is a homogeneous mixture including the two or more different types of silicon-based precursors. In some cases, applying a single-phase sol can allow for the formation of a coating of silica-based ceramic on the porous support membrane having a number of desirable properties such as a relatively high loading and / or a substantially uniform distribution of functional groups (e.g., quaternary ammonium groups) in the coating.

[0244] In some embodiments, prior to and / or during the step of applying the silicon-containing precursor sol to the porous support membrane, the silicon-containing precursor sol is a single-phase sol. For example, in embodiments in which the silicon-containing precursor sol includes two or more different types of silicon-based precursors (e.g., both a silane including a functional group such as a quaternary ammonium group and a silane not including such a functional group), the silicon-containing precursor sol is a homogeneous mixture including the two or more different types of silicon-based precursors. In some cases, applying a single-phase sol can allow for the formation of a coating of silica-based ceramic on the porous support membrane having a number of desirable properties such as a relatively high loading and / or a substantially uniform distribution of functional groups (e.g., quaternary ammonium groups) in the coating. Figure 6 ​In some embodiments, the solution 270 is applied to the porous support membrane prior to the step of aging the silicon-containing precursor sol. In some embodiments, the aging can occur for at least zero minutes, at least 30 minutes, at least two hours, or more, from the time the precursor materials are mixed together to form the sol. In some embodiments, the aging can occur for less than or equal to one week, less than or equal to 48 hours, less than or equal to 24 hours, or less. Combinations of these ranges are possible. For example, in some embodiments, the aging can occur for at least zero minutes and less than or equal to one week, for greater than or equal to 30 minutes and less than or equal to 48 hours, or for greater than or equal to two hours and less than or equal to 24 hours. In some embodiments, the temperature of the silicon-containing precursor sol during the aging is at least 0 °C, at least 20 °C, at least 30 °C, or higher. In some embodiments, the temperature of the silicon-containing precursor sol during the aging is less than or equal to 80 °C, less than or equal to 60 °C, less than or equal to 50 °C, or lower. Combinations of these ranges are possible. For example, in some embodiments, the temperature of the silicon-containing precursor sol during the aging is at least 0 °C and less than or equal to 80 °C, at least 20 °C and less than or equal to 60 °C, or at least 30 °C and less than or equal to 50 °C. In some cases, the silicon-containing precursor sol is aged in an open environment (e.g., open to ambient air), while in some embodiments, the converting step is performed in a sealed environment (e.g., in an environment that is fluidly isolated from ambient air). Aging in an open environment can allow for at least partial evaporation during the aging, which can be desirable in some, but not necessarily all, embodiments. Aging in a sealed environment reduces or eliminates evaporation during the aging, which can be desirable in some, but not necessarily all, embodiments.

[0245] In some embodiments, the porous support membrane containing at least a portion of the silicon-containing precursor sol is removed from the solution from which the silicon-containing precursor sol was applied, and the step of converting the silicon-containing precursor sol to a silica-based ceramic is performed. For example, referring now to step 3 in Figure 6 In some embodiments, the porous support membrane containing at least a portion of the silicon-containing precursor sol is removed from the solution from which the silicon-containing precursor sol was applied, and the step of converting the silicon-containing precursor sol to a silica-based ceramic is performed. For example, referring now to step 3 in

[0246] In some embodiments, the step of converting the silicon-containing precursor sol that coats at least a portion of the porous support membrane into a silica-based ceramic (e.g., via hydrolysis and condensation reactions) is performed for at least one second, at least 1 minute, at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, or more. In some embodiments, the step of converting the silicon-containing precursor sol that coats at least a portion of the porous support membrane into a silica-based ceramic is performed for less than or equal to 2 weeks, less than or equal to 1 week, less than or equal to 96 hours, less than or equal to 48 hours, less than or equal to 24 hours, or less. Combinations of these ranges are possible. For example, in some embodiments, the step of converting is performed for at least 1 second and less than or equal to 2 weeks, at least 2 hours and less than or equal to 48 hours, or at least 4 hours and less than or equal to 24 hours. The step of converting the silicon-containing precursor sol that coats at least a portion of the porous support membrane into a silica-based ceramic (e.g., via hydrolysis and condensation reactions) can be performed under any of a variety of conditions. In some cases, the conversion step is performed in an open environment (e.g., open to ambient air), while in some embodiments, the conversion step is performed in a sealed environment (e.g., in an environment that is fluidly isolated from ambient air). In some embodiments, the conversion step is performed in an environment having a humidity of at least 0% and up to 100% humidity.

[0247] The step of converting the silicon-containing precursor sol that coats at least a portion of the porous support membrane into a silica-based ceramic (e.g., via hydrolysis and condensation reactions) can be performed at any of a variety of temperatures, depending on the composition of the silicon-containing precursor sol and the desired properties of the anion exchange membrane. In some embodiments, the conversion step occurs at room temperature or cooler, while in some embodiments, the conversion step occurs at an elevated temperature. In some such cases, the coated porous support membrane is held in a desiccator (e.g., an oven) during the conversion step. For example, Figure 6During at least a portion of step 3, the exemplary coated porous support 20 is optionally maintained in a dryer 24, according to some embodiments. In some embodiments, the conversion step is performed with the coated porous support membrane maintained in an environment having a temperature greater than or equal to 0 °C, greater than or equal to 20 °C, or higher. In some embodiments, the conversion step is performed with the coated porous support membrane maintained in an environment having a temperature less than or equal to 150 °C, less than or equal to 80 °C, less than or equal to 60 °C, or lower. Combinations of these ranges are possible. For example, in some embodiments, the conversion step is performed with the coated porous support membrane maintained in an environment having a temperature greater than or equal to 0 °C and less than or equal to 150 °C, greater than or equal to 0 °C and less than or equal to 80 °C, or greater than or equal to 20 °C and less than or equal to 60 °C. The temperature of the conditions under which the conversion step (e.g., hydrolysis and condensation of a silicon-containing precursor sol to form a silica-based ceramic) occurs can be relatively low compared to certain prior art techniques for forming ceramics, such as high-temperature sintering and calcination. In some cases, the use of relatively low temperatures to form a silica-based ceramic allows for a reduction in the cost and resources required to manufacture anion exchange membranes compared to certain prior art techniques.

[0248] In some embodiments, the conversion step can be performed with the coated porous support membrane positioned on or in contact with a surface. For example, in some embodiments, the conversion step can be performed with the coated porous support membrane positioned on a relatively flat surface or a relatively flat and porous surface. However, it should be understood that the coated porous support membrane is not necessarily positioned on or in contact with a surface during the conversion step. In some embodiments, the coated porous support membrane is positioned in a horizontal orientation relative to the surface (e.g., in a horizontal orientation relative to an oven surface), while in some embodiments, the coated porous support membrane is positioned in a vertical orientation relative to the surface (e.g., in a vertical orientation relative to an oven surface).

[0249] In some embodiments, the converting step can optionally be terminated to end Step 3. For example, in some embodiments, the reactions (e.g., hydrolysis and condensation reactions) that occur during the converting step can be quenched by applying an aqueous solution. The aqueous solution can be applied using standard coating processes such as dip coating, spray coating, doctor blade coating, screen printing. For example, in some embodiments, quenching the reactions includes contacting the converted coated porous support membrane with an aqueous solution (e.g., via applying an aqueous solution to the converted coated porous support membrane, via immersing the coated porous support membrane into an aqueous solution, etc.). In some embodiments, the aqueous solution used to quench the reactions has a pH greater than or equal to -1, greater than or equal to zero, greater than or equal to 1, greater than or equal to 2, greater than or equal to 3, greater than or equal to 4, greater than or equal to 5, greater than or equal to 6, greater than or equal to 7, greater than or equal to 8, greater than or equal to 9, greater than or equal to 10, or greater. In some embodiments, the aqueous solution used to quench the reactions has a pH less than or equal to 14, less than or equal to 13, less than or equal to 12, less than or equal to 11, less than or equal to 10, less than or equal to 9, less than or equal to 8, less than or equal to 7, less than or equal to 6, less than or equal to 5, less than or equal to 4, less than or equal to 3, or less. Combinations of these ranges are possible. For example, in some embodiments, the aqueous solution used to quench the reactions has a pH greater than or equal to -1 and less than or equal to 14, greater than or equal to -1 and less than or equal to 7, greater than or equal to 5 and less than or equal to 7.

[0250] In some cases, it is desirable to remove excess silica-based ceramic from the anion exchange membrane (e.g., to reduce or eliminate surface excess). The excess silica-based ceramic can be removed using any of a variety of suitable methods. Exemplary methods include, but are not limited to, removal via mechanical squeegee, removal via air knife, and / or removal via heating (e.g., to an elevated temperature).

[0251] In some embodiments, the method for manufacturing anion exchange membranes described herein is completed after step 3 above. For example, in some embodiments, the membrane 282 produced after step 3 is a fully manufactured anion exchange membrane (e.g., the anion exchange membrane 150 described herein). In some cases, the steps of the above method may be repeated. For example, in some embodiments, steps 2 and 3 of the manufacturing method may be repeated. In some cases, repeating steps 2 and 3 may result in an increased coating of silica-based ceramics on and / or within the porous support membrane. For example, repeating steps 2 and 3 may allow a silica-containing precursor sol to penetrate into areas of the porous support membrane that were not penetrated by the silica-containing precursor sol during the previous step 2. In some cases, such repetition of steps 2 and 3 may result in the porous support membrane being filled with up to 100% silica-based ceramics. However, it should be understood that in some cases, repeating steps 2 and 3 too many times may result in an excessive buildup of silica-based ceramics on the surface of the porous support membrane. In other words, in some cases, a silica-based ceramic layer that is too thick may form on the outer surface of the anion exchange membrane, which may be detrimental to the performance of the anion exchange membrane in certain applications. It has been observed that, in some cases, performing steps 2 and 3 a total of 1 to 3 times can impart beneficial performance characteristics to the anion exchange membrane. It has also been observed that, in some cases, performing steps 2 and 3 a total of 1 to 6 times (e.g., 4 to 6 times) can impart beneficial performance characteristics to the anion exchange membrane.

[0252] As described above, in some implementations, it is possible to complete the process as described above and as follows: Figure 6 Step 3, as shown, prepares the fully manufactured anion exchange membrane. For example, in some embodiments where the silica-containing precursor sol includes a component containing functional groups desired to be present in the finished anion exchange membrane (e.g., a silane containing a quaternary ammonium group), these functional groups can be present in the anion exchange membrane produced after step 3, thus making the anion exchange membrane produced at the end of step 3 suitable for certain applications without further modification. As a non-limiting example, in some embodiments where the silica-containing precursor sol includes a tetraalkyl orthosilicate (e.g., TEOS) and a trimekrylalkyl-N,N,N-trialkylammonium (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium, TMAPS) as precursors, further modification of the anion exchange membrane may not be necessary after completing step 3, at least because the anion exchange membrane at this stage contains quaternary ammonium groups.

[0253] However, in some embodiments, one or more additional steps can be performed after step 3 of the methods described herein. For example, in some embodiments, the porous support membrane coated with a silica-based ceramic does not contain a functional group (e.g., a quaternary ammonium group) that is desired to be present in the anion exchange membrane completed after step 3. For example, in some embodiments, the silicon-containing precursor sol used to coat the porous support membrane does not contain a component that contains the desired functional group. As one non-limiting example, in some embodiments, the silicon-containing precursor sol contains tetraalkyl orthosilicate (e.g., TEOS) and a silane containing a moiety containing a leaving group (e.g., a halogen group, a tosylate group, a trifluoromethane group) as a precursor. In some such cases, it can be necessary to perform a further chemical reaction to convert the moiety containing the leaving group to the desired quaternary ammonium group (e.g., via nucleophilic substitution). Thus, in some cases, a further chemical reaction can be performed to form the desired functional group.

[0254] In some embodiments, an optional step of exposing the coated porous support membrane after step 3 to water can be performed. For example, as shown in FIG. 2B, an optional step 4 in which the membrane 282 is contacted with water can be performed. In some embodiments, exposing the coated porous support membrane after step 3 to water can result in the removal of certain components that can not be desired in subsequent steps of the manufacturing process. For example, in some embodiments, exposing the coated porous support membrane to water can remove acid from the membrane structure. Water can be applied using one or more standard coating processes such as dipping, spraying, doctor blade, and screen printing. Figure 6

[0255] In some embodiments, the method for forming an anion exchange membrane includes a step of exposing a porous support membrane having at least a portion thereof coated with a silica-based ceramic containing a moiety containing a leaving group to an amine. As shown in FIG. 2C, in some embodiments, the membrane 282 includes a porous support membrane coated with a silica-based ceramic containing a moiety containing a leaving group, and the membrane 282 is exposed to an amine in solution 272 during optional step 5. In some embodiments, the method further reacts the amine with the moiety to release the leaving group and form a quaternary ammonium group covalently bonded to the silica-based ceramic. In some such cases, the step of exposing the porous support membrane to an amine and reacting the moiety with the amine to form a quaternary ammonium group results in the anion exchange membrane containing (e.g., covalently bonded to the silica-based ceramic) a quaternary ammonium group. Figure 6

[0256] ​​In some embodiments, the silica-based ceramic comprising a moiety comprising a leaving group comprises a relatively high percentage of silicon. For example, in some embodiments, the silica-based ceramic comprises Si in an amount greater than or equal to 6 wt%, greater than or equal to 10 wt%, greater than or equal to 12 wt%, greater than or equal to 15 wt%, greater than or equal to 17 wt%, greater than or equal to 20 wt%, greater than or equal to 24 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 60 wt%, or greater, based on the silica-based ceramic. In some embodiments, the silica-based ceramic comprises Si in an amount less than or equal to 60 wt%, less than or equal to 50 wt%, less than or equal to 47 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, less than or equal to 28 wt%, less than or equal to 26 wt%, less than or equal to 24 wt%, less than or equal to 22 wt%, less than or equal to 20 wt%, less than or equal to 17 wt%, or less, based on the silica-based ceramic. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic comprises Si in an amount greater than or equal to 6 wt% and less than or equal to 60 wt%, or greater than or equal to 17 wt% and less than or equal to 26 wt%, based on the silica-based ceramic.

[0257] The moiety comprising a leaving group can be any functional group that can release a leaving group to form a quaternary ammonium group upon a nucleophilic substitution step. For example, in some embodiments, the moiety comprising a leaving group is a substituted alkyl group (e.g., a haloalkyl group, such as chloropropyl).

[0258] The amine can be any amine suitable for reacting with the moiety comprising a leaving group to form a quaternary ammonium group. In some embodiments, the amine is a tertiary amine. In some embodiments, the amine is trimethylamine.

[0259] Exposing the porous support membrane coated with the silica-based ceramic comprising a moiety comprising a leaving group to an amine reagent can include the step of applying the amine to the coated membrane in any of a variety of suitable ways. For example, as described above, in some embodiments, the exposing step includes exposing the coated porous support membrane to a solution comprising the amine (e.g., a solution of trimethylamine in water), as described above. Figure 6In some cases, the amine can be applied to the coated porous support membrane using a standard coating process such as dip coating, spray coating, roll coating, doctor blade coating, or screen printing. In some embodiments, the amine (e.g., trimethylamine) can be applied to the coated porous support membrane by applying (e.g., via immersion) a solution comprising at least 1 vol.%, at least 5 vol.%, at least 10 vol.%, at least 15 vol.%, at least 20 vol.%, or more amine (e.g., trimethylamine). In some embodiments, the amine (e.g., trimethylamine) can be applied to the coated porous support membrane by applying (e.g., via immersion) a solution comprising less than or equal to 50 vol.%, less than or equal to 40 vol.%, less than or equal to 30 vol.%, less than or equal to 25 vol.%, less than or equal to 20 vol.%, less than or equal to 15 vol.%, less than or equal to 10 vol.%, or less amine (e.g., trimethylamine). Combinations of these ranges are possible. For example, in some embodiments, the amine can be applied to the coated porous support membrane by applying a solution comprising greater than or equal to 1 vol.% and less than or equal to 50 vol.%, greater than or equal to 10 vol.% and less than or equal to 50 vol.%, or greater than or equal to 20 vol.% and less than or equal to 50 vol.% amine (e.g., trimethylamine).

[0260] In some embodiments, the step of reacting the moiety containing a leaving group with an amine to form a quaternary ammonium group is performed using a solution comprising the amine maintained at a suitable temperature. For example, in some embodiments, the temperature of the solution comprising the amine used for the reaction is greater than or equal to 0 °C, greater than or equal to 20 °C, or higher. In some embodiments, the temperature of the solution comprising the amine used for the reaction is less than or equal to 100 °C, less than or equal to 60 °C, less than or equal to 50 °C, or lower. Combinations of these ranges are possible. For example, in some embodiments, the temperature of the solution comprising the solution comprising the amine used for the reaction is greater than or equal to 0 °C and less than or equal to 100 °C, greater than or equal to 0 °C and less than or equal to 60 °C, or greater than or equal to 20 °C and less than or equal to 50 °C. The duration of the oxidation reaction to convert the moiety containing a leaving group to a quaternary ammonium group can depend on the reaction kinetics as well as, for example, the concentration of the leaving group (e.g., a halogen group, such as a chlorine group) on or within the coated porous support comprising a silica-based ceramic. In some cases, the reaction can be performed for at least 1 minute, at least 30 minutes, at least 1 hour, or longer. In some cases, the reaction can be performed for less than or equal to 1 week, less than or equal to 48 hours, less than or equal to 24 hours, or less. Combinations of these ranges are possible. For example, in some embodiments, the reaction can be performed for greater than or equal to 1 minute and less than or equal to 1 week, greater than or equal to 30 minutes and less than or equal to 48 hours, or greater than or equal to 1 hour and less than or equal to 24 hours.

[0261] In some embodiments, an optional drying step can be performed on the anion exchange membrane after the amine is reacted with the moiety containing a leaving group to form a quaternary ammonium group. Figure 6 An optional step 6 is shown in which the reacted membrane 284 containing quaternary ammonium groups is dried by being held in an optional dryer 26, according to some embodiments. However, it is understood that in some embodiments, the drying step can be performed without holding the reacted anion exchange membrane in a dryer. In some embodiments, the step of drying the reacted anion exchange membrane containing quaternary ammonium groups is performed for at least 1 second, at least 1 minute, at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, or more. In some embodiments, the step of drying the reacted anion exchange membrane containing quaternary ammonium groups is performed for up to 24 hours, up to 2 days, up to one week, up to 2 weeks, or more. Combinations of these ranges are possible. For example, in some embodiments, the step of drying the reacted anion exchange membrane containing quaternary ammonium groups is performed for at least 1 second and up to 2 weeks, at least 2 hours and up to 2 days, or at least 4 hours and up to 24 hours. The step of drying the reacted anion exchange membrane containing quaternary ammonium groups can be performed under any of a variety of conditions. In some cases, the drying step is performed in an open environment (e.g., open to ambient air), while in some embodiments, the drying step is performed in a sealed environment (e.g., in an environment that is fluidly isolated from ambient air). In some embodiments, the drying step is performed in an environment having a humidity of at least 0% and up to 100% humidity.

[0262] The step of drying the reacted anion exchange membrane containing quaternary ammonium groups can be performed at any of a variety of temperatures. In some embodiments, the drying step occurs at room temperature or cooler, while in some embodiments, the drying step occurs at an elevated temperature. In some embodiments, the drying step is performed with the reacted anion exchange membrane held in an environment having a temperature greater than or equal to 0 °C, greater than or equal to 20 °C, or more. In some embodiments, the drying step is performed with the coated porous support membrane held in an environment having a temperature less than or equal to 150 °C, less than or equal to 80 °C, less than or equal to 60 °C, or less. Combinations of these ranges are possible. For example, in some embodiments, the drying step is performed with the reacted anion exchange membrane held in an environment having a temperature greater than or equal to 0 °C and less than or equal to 150 °C, greater than or equal to 0 °C and less than or equal to 80 °C, or greater than or equal to 20 °C and less than or equal to 60 °C. In some cases, the resulting anion exchange membrane after the reaction step and / or optional drying step can be suitable for use in any of a variety of applications.

[0263] In some embodiments, the anion exchange material described herein is not in the form of a membrane. For example, in some embodiments, the anion exchange material can comprise a silica-based ceramic comprising quaternary ammonium groups covalently bonded to the silica-based ceramic as described herein without being in the form of a membrane. In some such cases, the anion exchange material comprises a silica-based ceramic as described herein but does not necessarily include a porous support membrane (e.g., a silica-based ceramic is coated on and / or within). One non-limiting example of an anion exchange material that is not in the form of a membrane is an ion exchange resin. In some embodiments, the anion exchange material is in the form of a bead, e.g., formed using an emulsion method (e.g., as an anion exchange bead comprising a silica-based ceramic described herein). As a non-limiting example, Figure 7 A schematic of an anion exchange material 300 comprising a silica-based ceramic 150 is shown, according to some embodiments, wherein the anion exchange material 300 is in the form of a bead. According to some embodiments, as shown, Figure 7 the silica-based ceramic 150 comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, in some cases.

[0264] In some embodiments, the anion exchange material (e.g., resin) is in the form of a plurality of particles (e.g., powder) comprising functional groups (e.g., silica-based ceramic comprising quaternary ammonium groups). In some embodiments, the anion exchange material in the form of particles (e.g., powder) is formed by mechanically breaking the silica-based ceramic described herein (e.g., via any suitable technique known in the art, such as milling). The anion exchange material particles can be packed into an ion exchange column and used in any of a variety of applications. In some embodiments, the anion exchange material is in the form of a plurality of particles (e.g., powder) having an average maximum cross-sectional dimension greater than or equal to 1 pm, greater than or equal to 2 pm, greater than or equal to 5 pm, greater than or equal to 8 pm, greater than or equal to 10 pm, greater than or equal to 15 pm, greater than or equal to 20 pm, greater than or equal to 30 pm, greater than or equal to 50 pm, greater than or equal to 75 pm, greater than or equal to 100 pm, greater than or equal to 200 pm, greater than or equal to 500 pm, greater than or equal to 1 mm, or greater. In some embodiments, the anion exchange material is in the form of a plurality of particles (e.g., powder) having an average maximum cross-sectional dimension less than or equal to 10 mm, less than or equal to 5 mm, less than or equal to 2 mm, less than or equal to 1 mm, less than or equal to 500 pm, less than or equal to 200 pm, less than or equal to 100 pm, less than or equal to 80 pm, less than or equal to 60 pm, less than or equal to 50 pm, less than or equal to 40 pm, less than or equal to 25 pm, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange material is in the form of a plurality of particles (e.g., powder) having an average maximum cross-sectional dimension greater than or equal to 1 pm and less than or equal to 10 mm.

[0265] In some embodiments, an anion exchange material (e.g., bead, particle) comprising a silica-based ceramic comprising covalently bonded quaternary ammonium groups is provided, wherein, as described above, the silica-based ceramic comprises a relatively large amount of Si in the silica-based ceramic. In some embodiments, as described above, the silica-based ceramic of the anion exchange material (e.g., bead) comprises relatively small pores (e.g., pores having a number average pore size less than or equal to 10 nm or less). In some embodiments, the anion exchange material (e.g., in the form of a bead) has a relatively high anion exchange capacity (e.g., greater than 0.01 meq / g anion exchange membrane).

[0266] In some embodiments, anion exchange material that is not in the form of a membrane can be prepared by reacting a silica-based ceramic containing moieties containing leaving groups with an amine, where the silica-based ceramic is not part of a membrane. For example, in some embodiments, an anion exchange membrane comprising a silica-based ceramic in the form of a resin (e.g., a resin comprising a plurality of particles or beads) and comprising quaternary ammonium groups can be manufactured using reaction steps similar to those described above with respect to anion exchange membranes. For example, some embodiments include exposing a resin comprising a silica-based ceramic to an amine (e.g., triethylamine) as described above, the silica-based ceramic comprising moieties containing leaving groups (e.g., substituted alkyl groups containing halogen groups). In some embodiments, the method further releases the leaving groups and forms quaternary ammonium groups.

[0267] In some embodiments, the resin of silica-based ceramic comprises Si in an amount greater than or equal to 6 wt%, greater than or equal to 10 wt%, greater than or equal to 12 wt%, greater than or equal to 15 wt%, greater than or equal to 17 wt%, greater than or equal to 20 wt%, greater than or equal to 24 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 60 wt%, or greater in the silica-based ceramic. In some embodiments, the resin of silica-based ceramic comprises Si in an amount less than or equal to 60 wt%, less than or equal to 50 wt%, less than or equal to 47 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, less than or equal to 28 wt%, less than or equal to 26 wt%, less than or equal to 24 wt%, less than or equal to 22 wt%, less than or equal to 20 wt%, less than or equal to 17 wt%, or less in the silica-based ceramic. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic comprises Si in an amount greater than or equal to 6 wt% and less than or equal to 60 wt%, or greater than or equal to 17 wt% and less than or equal to 26 wt% in the resin of silica-based ceramic. In some embodiments, the resin of silica-based ceramic comprising Si in an amount according to the above wt% ranges is a resin comprising leaving groups as described herein.

[0268] The anion exchange membranes and materials described herein can be used for any of a variety of applications. For example, in some embodiments, the anion exchange membranes described herein are used in electrochemical applications. In some cases, electrochemical applications involve the application of an electric current or voltage in order to, for example, effectuate the separation of charged ionic species. The use of an anion exchange membrane in an electrochemical application can include contacting the anion exchange membrane with an electrolyte. In some embodiments, the use of an anion exchange membrane in an electrochemical application can include passing an electric current through an electrode in electrical communication with an electrolyte. For example, in some embodiments, an anion exchange membrane is incorporated into an electrochemical device (e.g., a battery, a fuel cell, an electrolytic device, etc.). In some such embodiments, the electrochemical device includes an electrolyte (e.g., a fluid (liquid) electrolyte or a solid electrolyte) in contact with the anion exchange membrane and an electrode in electrical communication with the electrolyte. In some embodiments, the electrochemical device contains one or more gases (e.g., in contact with the anion exchange membrane) during at least a portion of a charging and / or discharging process (e.g., a fuel cell). Examples of such gases include, but are not limited to, oxygen (O2), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and combinations thereof. In some cases, during operation of the electrochemical device (e.g., a charging or discharging process), an electric current is passed through the electrode (e.g., during an electrochemical reaction). In some embodiments in which an anion exchange membrane is incorporated into an electrochemical device, the anion exchange membrane is paired with an anion exchange membrane. In some cases, an anion exchange membrane can be loaded into a cell, and multiple such cells can be loaded into a stack comprising more than one anion exchange membrane. Non-limiting examples of electrochemical applications of anion exchange membranes include electrodialysis, batteries (e.g., redox flow batteries), fuel cells, chemical commodity production (e.g., chlor-alkali production), electrolysis, demineralization, wastewater treatment, chromatography, electrodeionization, desalination (e.g., enhanced oil recovery (EOR) desalination, organic wastewater desalination), removal of chemical contaminants from wastewater (e.g., removal of ammonia from wastewater), water treatment (e.g., mine runoff and tailings treatment), food and beverage production, dairy / whey purification, wine stabilization, biopurification, biochemical production, coating (e.g., electrodeposition coating), desalination processes, ultrapure water production, recovery of electroplating solutions, recovery of amines, acid recovery processes, caustic recovery processes, and acid removal processes (e.g., removal of tartaric acid, malic acid, citric acid). It should be appreciated that, in some cases, an anion exchange membrane can be used for separation applications other than applications involving the application of an electric field. For example, in some embodiments, an anion exchange membrane is used in dialysis techniques. One non-limiting example includes diffusion dialysis (DD). Diffusion dialysis can be used in acid recovery processes (e.g., using a concentration gradient to selectively transport anions).

[0269] In some embodiments, the anion exchange membranes described herein are used as adsorbent materials. For example, in some embodiments, the anion exchange membranes are incorporated into an adsorption device. In some such embodiments, the anion exchange membranes are used as adsorbent materials to remove a liquid from a gas stream. In some cases, the anion exchange membranes are used as adsorbent materials to remove dissolved ions from a liquid stream (e.g., in an ion exchange process). In some embodiments, using the anion exchange membranes as adsorbent materials includes flowing a fluid through the anion exchange membranes. In some such embodiments, using the anion exchange membranes as adsorbent materials further includes adsorbing a component of the fluid that flows through the anion exchange membranes (e.g., the liquid when removing the liquid from the gas stream, the ions when removing the ions from the liquid stream). Non-limiting examples of using the anion exchange membranes described herein as adsorbent materials include using the anion exchange membranes in pervaporator systems, dehumidifier systems, and / or desiccant or climate control systems.

[0270] In some embodiments, the anion exchange membranes described herein are used in separation applications. In some such embodiments, the anion exchange membranes are used in separation applications that include applying a transmembrane pressure to the anion exchange membranes. Non-limiting examples of separation applications in which the anion exchange membranes are used by applying a transmembrane pressure to the anion exchange membranes include reverse osmosis, microfiltration (e.g., organic solvent microfiltration, aqueous solvent microfiltration), nanofiltration (e.g., organic solvent nanofiltration, aqueous solvent nanofiltration), and ultrafiltration applications. For example, in some embodiments, the anion exchange membranes are incorporated into a reverse osmosis device, a filtration device, or an ultrafiltration device. In some cases, applying a transmembrane pressure to the anion exchange membranes can include contacting the anion exchange membranes with a liquid (e.g., a liquid solution) and applying a static or hydraulic pressure to the liquid such that a transmembrane pressure is applied to the anion exchange membranes. In some such embodiments, at least a portion of the liquid passes through the anion exchange membranes (e.g., as a permeate from a first side of the anion exchange membranes to a second side of the anion exchange membranes).

[0271] As described above, in some embodiments, anion exchange materials that are not in the form of a membrane (e.g., in the form of a resin comprising a plurality of silica-based ceramic particles or beads) are also described herein. Anion exchange materials that can comprise silica-based ceramics containing functional groups as described herein can be used in any of a variety of applications. For example, in some embodiments, resins comprising the anion exchange materials described herein are packed into ion exchange columns. In some such embodiments, the ion exchange columns comprising the anion exchange materials can be used in waste treatment (e.g., nuclear waste treatment) and purification processes such as ultra-pure water production or protein and biologic purification.

[0272] Definitions of specific functional groups and chemical terms are described below. For purposes of this application, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75thEd., inside cover, and specific functional group terms are generally defined as in Organic Chemistry, Thomas Sorrell, University Science Books, Sausalito: 1999, the entire contents of which are incorporated herein by reference.

[0273] As used herein, the term "aliphatic" refers to alkyl, alkenyl, alkynyl, and carbocyclic groups. Likewise, the term "heteroaliphatic" refers to heteroalkyl, heteroalkenyl, heteroalkynyl, and heterocyclic groups.

[0274] The term "alkyl" is provided its ordinary meaning in the art and refers to a radical of a saturated aliphatic group, including straight-chain alkyl, branched-chain alkyl, cycloalkyl (alicyclic), alkyl-substituted cycloalkyl, and cycloalkyl-substituted alkyl groups. In some instances, an alkyl group can be lower alkyl, i.e., an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl). In some embodiments, straight-chain or branched-chain alkyl groups can have 30 or fewer carbon atoms in their backbone, and in some cases, 20 or fewer carbon atoms in their backbone. In some embodiments, straight-chain or branched-chain alkyl groups can have 12 or fewer, 6 or fewer, or 4 or fewer carbon atoms in their backbone (e.g., C1 to C 12 , C3 to C 12 for branched-chain). Likewise, cycloalkyl groups can have from 3 to 10 carbon atoms in their ring structure, or 5, 6, or 7 carbons in the ring structure. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, t-butyl, cyclobutyl, hexyl, and cyclohexyl.

[0275] The term "alkylene" as used herein refers to a divalent alkyl group. An "alkylene" is a polymethylene, i.e., -(CH2) z - where z is a positive integer, e.g., 1 to 20, 1 to 10, 1 to 6, 1 to 4, 1 to 3, 1 to 2, or 2 to 3. A substituted alkylene chain is a polymethylene in which one or more of the methylene hydrogen atoms is replaced by a substituent. Suitable substituents include those described herein with respect to substituted aliphatic groups. An alkylene group can be cyclic or acyclic, branched or unbranched, substituted or unsubstituted.

[0276] In general, the suffix "-ylidene" is used to describe divalent groups. Thus, any term defined herein can be modified with the suffix "-ylidene" to describe the divalent form of the moiety. For example, a divalent carbocyclic ring is an "carbocyclylidene", a divalent aryl ring is an "arylidene", a divalent phenyl ring is a "phenylidene", a divalent heterocyclic ring is a "heterocyclylidene", a divalent heteroaryl ring is a "heteroarylidene", a divalent alkyl chain is an "alkylidene", a divalent alkenyl chain is an "alkenylidene", a divalent alkynyl chain is an "alkynylidene", a divalent heteroalkyl chain is a "heteroalkylidene", a divalent heteroalkenyl chain is a "heteroalkenylidene", a divalent heteroalkynyl chain is a "heteroalkynylidene", and the like.

[0277] The term "aryl" is provided in its ordinary sense within the art and refers to an optionally substituted aromatic carbocyclic radical having a single ring (e.g., phenyl), multiple rings (e.g., biphenyl), or multiple condensed rings wherein at least one ring is aromatic (e.g., 1,2,3,4-tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl). That is, at least one ring can have a conjugated pi-electron system, while other adjacent rings can be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, and / or heterocyclyl. As described herein, aryl groups can be optionally substituted. Substituents include, but are not limited to, any of the aforementioned substituents that result in the formation of a stable compound, i.e., the substituents detailed with respect to aliphatic moieties or with respect to other moieties disclosed herein. In some instances, aryl is a stable monocyclic or polycyclic unsaturated moiety preferably having 3 to 14 carbon atoms, each of which can be substituted or unsubstituted. "Carbocyclic aryl" refers to aryl groups in which the ring atoms on the aromatic ring are carbon atoms. Carbocyclic aryl includes monocyclic carbocyclic aryl and polycyclic or fused compounds (e.g., two or more adjacent ring atoms are shared by two adjacent rings), such as naphthyl.

[0278] The term "arylene" as used herein refers to an aryl diradical derived by the removal of two hydrogen atoms from an aryl group as defined herein. Arylene groups can be substituted or unsubstituted. Arylene substituents include, but are not limited to, any of the substituents described herein that result in the formation of a stable moiety. In addition, arylene groups can be incorporated as linking groups in an alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, or heteroalkynylene group as defined herein. Arylene groups can be branched or unbranched.

[0279] The terms "halo" and "halogen" as used herein refer to an atom selected from fluorine, chlorine, bromine, and iodine.

[0280] The term "alkoxy" as used herein refers to an alkyl group, as previously defined, attached to the parent molecular moiety through an oxygen atom or through a sulfur atom. In certain embodiments, the alkyl group comprises 1 to 20 aliphatic carbon atoms. In certain further embodiments, the alkyl group comprises 1 to 10 aliphatic carbon atoms. In other embodiments, the alkyl, alkenyl, and alkynyl groups employed in the present application comprise 1 to 8 aliphatic carbon atoms. In yet other embodiments, the alkyl group comprises 1 to 6 aliphatic carbon atoms. In still other embodiments, the alkyl group comprises 1 to 4 aliphatic carbon atoms. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propyloxy, isopropyloxy, n-butyloxy, t-butyloxy, neopentyloxy, and n-hexyloxy. Examples of thioalkyl groups include, but are not limited to, methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, and the like. The alkoxy group can be cyclic or acyclic, branched or unbranched, substituted or unsubstituted.

[0281] As used herein, quaternary ammonium groups include quaternary (-N + R x R y R z ) amine groups (e.g., quaternary ammonium salts), wherein R x , R y , and R z are independently aliphatic, cycloaliphatic, heteroaliphatic, heterocyclic, aryl, or heteroaryl moieties as defined herein. In some embodiments, quaternary ammonium groups include N + (C 1-4 alkyl)4salts.

[0282] The term “heterocyclyl” or “heterocycle” refers to a 3- to 14-membered non-aromatic ring system group having ring carbon atoms and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“3- to 14-membered heterocyclyl”). In heterocyclyl groups comprising one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, when valence permits. Heterocyclyl groups can be monocyclic (“monocyclic heterocyclyl”) or polycyclic (e.g., a fused, bridged, or spiro ring system, such as a bicyclic ring system (“bicyclic heterocyclyl”) or a tricyclic ring system (“tricyclic heterocyclyl”)), and can be saturated or can comprise one or more carbon-carbon double bonds or triple bonds. The ring system of a heterocyclyl polycycle can comprise one or more heteroatoms in one or both rings. “Heterocyclyl” also includes ring systems in which a heterocyclyl ring as defined above is fused to one or more carbocyclyl rings, wherein the point of attachment is on either the carbocyclyl or heterocyclyl ring; or includes ring systems in which a heterocyclyl ring as defined above is fused to one or more aryl or heteroaryl groups, wherein the point of attachment is on the heterocyclyl ring, and in such cases the number of ring members continues to indicate the number of ring members in the heterocyclyl ring system. Unless otherwise specified, each instance of a heterocyclyl group is independently unsubstituted (“unsubstituted heterocyclyl”) or substituted with one or more substituents (“substituted heterocyclyl”). In certain embodiments, a heterocyclyl group is an unsubstituted 3- to 14-membered heterocyclyl. In certain embodiments, a heterocyclyl group is a substituted 3- to 14-membered heterocyclyl.

[0283] The term “heteroaryl” refers to a 5- to 14-membered monocyclic or polycyclic (e.g., bicyclic, tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in a cyclic array) group having ring carbon atoms provided in the aromatic ring system and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5- to 14-membered heteroaryl”). In heteroaryl groups comprising one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, when valence permits. The ring system of a heteroaryl polycycle can comprise one or more heteroatoms in one or both rings. “Heteroaryl” includes ring systems in which a heteroaryl ring as defined above is fused to one or more carbocyclyl or heterocyclyl groups, wherein the point of attachment is on the heteroaryl ring, and in such cases the number of ring members continues to indicate the number of ring members in the heteroaryl ring system. “Heteroaryl” also includes ring systems in which a heteroaryl ring as defined above is fused to one or more aryl groups, wherein the point of attachment is on the aryl or heteroaryl ring, and in such cases the number of ring members indicates the number of ring members in the fused polycyclic (aryl / heteroaryl) ring system. Where one of the rings does not comprise a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, etc.), the point of attachment can be on either ring, i.e., on the ring with the heteroatom (e.g., 2-indolyl) or on the ring that does not comprise a heteroatom (e.g., 5-indolyl).

[0284] As used herein, "leaving group" (LG) is a term understood in the art to refer to a molecular fragment that donates a pair of electrons in a heterolytic bond cleavage, wherein the molecular fragment is an anion or a neutral molecule. As used herein, a leaving group can be an atom or a group that can be displaced by a nucleophile. See, e.g., Smith, March Advanced Organic Chemistry 6thEd. (501-502).

[0285] It will be understood that the above groups and / or compounds, as described herein, can be optionally substituted with any number of substituents or functional moieties. That is, any of the above groups can be optionally substituted. As used herein, the term "substituted" is contemplated to include all permissible substituents of organic compounds, "permissible" being in the context of the chemical rules of valence known to those of ordinary skill in the art. In general, the term "substituted" and substituents contemplated in the formulas of this application, whether preceded by the term "optionally" or not, refer to the replacement of a hydrogen radical in a given structure with a group other than hydrogen. When more than one position in any given structure can be substituted with more than one substituent, each position is independently substituted with the same or different substituents. It will be understood that "substituted" also includes substitution with a moiety that results in the formation of a stable compound, e.g., a compound that does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. In some instances, "substituted" can generally mean replacement of a hydrogen with a substituent as described herein. However, as used herein, "substituted" does not encompass replacement of a key functional group of a molecule by another group, e.g., such that the "substituted" functional group becomes a different functional group after substitution. For example, in this definition, "substituted phenyl" must still comprise a phenyl moiety, and cannot be modified by substitution to become, e.g., a pyridine ring. In a broad aspect, permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and nonaromatic, substituents of organic compounds. Exemplary substituents include, e.g., those described herein. Permissible substituents can be one or more and the same or different for each atom to which they are attached. For organic compounds, a heteroatom such as nitrogen can have a hydrogen substituent and / or any permissible substituents of organic compounds described herein that satisfy the valencies of the heteroatom. Further, this application is not intended to be limited in any way by the permissible substituents of organic compounds. Combinations of substituents and variables envisioned by this application are preferably those that result in the formation of stable compounds. The term "stable", as used herein, preferably refers to compounds that possess sufficient stability to permit manufacture and that remain intact for a sufficient period of time to be detected and preferably for a sufficient period of time to be used for the purposes detailed herein.

[0286] Examples of substituents include, but are not limited to, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamide, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moiety, -CF3, -CN, aryl, aryloxy, perhaloalkoxy, aralkyloxy, heteroaryl, heteroaryloxy, heteroarylalkyl, heteroaralkoxy, azido, amino, halide, alkylthio, oxo, acylalkyl, carboxyl ester, carboxamido, acyloxy, aminoalkyl, alkylaminoaryl, alkylaryl, alkylaminoalkyl, alkoxyaryl, arylamino, aralkylamino, alkylsulfonyl, amidoalkylaryl, amidoaryl, hydroxyalkyl, haloalkyl, alkylaminoalkylcarboxyl, aminoamidoalkyl, cyano, alkoxyalkyl, perhaloalkyl, arylalkoxyalkyl, and the like.

[0287] U.S. Provisional Application Serial No. 62 / 857,227, filed June 4, 2019, entitled “CERAMIC ANION EXCHANGE MATERIALS,” is incorporated by reference herein in its entirety for all purposes.

[0288] The following examples are intended to illustrate certain embodiments of the present application, and are not intended to exemplify the full scope of the application.

[0289] Example 1

[0290] This example illustrates performance and structural properties of an exemplary anion exchange membrane. The anion exchange membranes of this example were fabricated on a nonwoven glass porous support membrane with polymerized edges according to the following procedure. The porous support membrane was made of binderless borosilicate glass fibers with an average / mean pore size of 1 micron. The porous support membrane was initially 254 microns thick prior to sol-gel impregnation. The porous support membrane was initially edged with a UV-curable silicone to form a disc with an outer diameter of 35 mm and an inner active area diameter of 10 mm to 15 mm. An initial mixture was prepared comprising 65:35 mass ratio of TEOS: 50% N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) in methanol, and 0.3 M hydrochloric acid was added to achieve a final water: silicon molar ratio (R) of 2 and 4. The mixture was stirred and heated to 40 °C for 4 hours, then applied to the porous support membrane. The coated porous support membrane was allowed to dry overnight, and a group with a second coating was applied following the same procedure for comparison. The membranes were soaked in 0.5 M NaCl and then characterized, where they were found to have an apparent anion permselectivity of 82% to 96% (Table 1). Figure 8A) ; a chloride conductivity of 0.0008 S / cm to 0.001 S / cm Figure 8B ) ; and a permeate water permeance of 2.95 mL.m -2 . hr -1 . bar -1 to 5.2 mL.m -2 . hr -1 . bar -1 . The anion exchange capacity of similarly prepared samples was 0.61 meq / g to 0.95 meq / g. SAXS analysis (based on data shown in Figure 8C and model fitting) showed that the membrane prepared with a water: silicon molar ratio equal to 4 had an average volume porosity of 9.5%, Figure 8D an average pore radius of 2.5 nm, and an average log-normal polydispersity index of 0.24.

[0291] Example 2

[0292] This example illustrates the structural properties of an exemplary anion exchange membrane. The anion exchange membrane of this example was fabricated on a non-woven glass porous support membrane with polymerized edges according to the following steps. The porous support membrane was made of binderless borosilicate glass fibers with an average / mean pore size of 1 micron. The porous support membrane was initially 254 microns thick prior to sol-gel impregnation. The porous support membrane was initially edged with a UV-curable silicone to form a disc with an outer diameter of 35 mm and an inner active area diameter of 10 mm to 15 mm. An initial mixture comprising 50% N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) in TEOS:methanol at different molar ratios (2:1, 4:1, 6:1, 8:1, and 10:1) was prepared and 0.3 M hydrochloric acid was added to each initial mixture to achieve a final water: silicon molar ratio (R) of 2. The mixture was stirred and heated to 40 °C for 4 hours before being applied to the porous support membrane. The coated porous support membrane was allowed to dry overnight and a second coating was applied following the same procedure. SAXS analysis (based on data shown in Figure 9A and Teubner-Strey model fitting) showed that the membrane had pores with a radius of to and a volume porosity of 4% to 22%. As shown in Figures 9B to 9C , a 6:1 TEOS:TMAPS ratio resulted in a pore radius of 2.5 nm and a volume porosity of 21%. Anion exchange capacity of the same membranes is shown. Figure 9D

[0293] Example 3

[0294] ​​This example illustrates the performance characteristics and structural characteristics of exemplary anion exchange membranes. Anion exchange membranes of this example were fabricated on non-woven porous polymer support membranes of two different thicknesses (190 microns and 210 microns) without polymer edge seals following similar procedures as described in Example 2, but with a molar ratio of TEOS to TMAPS of 6:1 and an R value of 2. The mixture was aged at 40 °C for 1 hour, then subjected to an additional open aging step at 100 °C for 30 minutes, then it was coated onto the porous support. The coated support was allowed to dry at room temperature for 2 hours, then the coating step was repeated. After the final membrane had 4 layers of coating it was allowed to dry overnight. The anion exchange membranes were soaked in a 0.5 M NaCl solution and then characterized. The anion exchange membranes were found to have an apparent anion permselectivity of 92% to 94% (see Figure 10A ), and a chloride ion conductivity of 0.0062 S / cm to 0.0079 S / cm (see Figure 10B ). The average anion exchange capacity of similarly prepared membranes was found to be 1.4 meq / g.

[0295] FIG. 11 shows a cross-sectional SEM image of one of the anion exchange membranes of this example, in which the cross-section includes a non-woven porous polymer support membrane showing dark polymer fibers occupying the central horizontal region of the cross-section. Some of the polymer fibers extend horizontally in the plane of the image, while others extend in a direction perpendicular to the plane of the image and appear as circles in the cross-section. The cross-section contains the nanoporous silica-based ceramic of the anion exchange membrane as a dense, uniform, plate-like, lighter contrast material surrounding the porous support membrane on and within the porous support membrane.

[0296] Example 4

[0297] This example illustrates the performance characteristics and structural characteristics of exemplary anion exchange membranes. Anion exchange membranes of this example were fabricated on non-woven porous glass support membranes with polymer edge seals following similar procedures as described in Example 2, but with a molar ratio of TEOS to TMAPS of 6:1, an R value of 2, and with 2 to 5 layers of coating. The time spent coating the sol on the samples (15 minutes to 60 minutes) and whether the samples were dried in an open or closed environment were varied to study performance changes. All samples were soaked in a 0.5 M NaCl solution and then characterized. The apparent permselectivity of these samples was found to be 88% to 100% (see Figure 11A ). The chloride ion conductivity was 0.0009 S / cm to 0.003 S / cm (see Figure 11B ).

[0298] Figure 11C A cross-sectional SEM image of one of the anion exchange membranes of this example is shown inFigure 11C In this case, the cross-section includes a nonwoven porous polymer support film showing dark polymer fibers 401 occupying the central horizontal region of the cross-section. Some of the polymer fibers extend horizontally in the plane of the figure, while others extend in a direction perpendicular to the plane of the figure and are shown as circular in the cross-section. The cross-section contains a nanoporous silica-based ceramic as a dense, uniform, plate-like, lighter contrast material 402 on and within the porous support film of anion exchange membrane.

[0299] While several embodiments of the present application have been described and illustrated herein, those of ordinary skill in the art will contemplate a variety of other means and / or structures for implementing the functions and / or

[0300] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0301] The phrase "and / or," as used herein in the specification and in the claims, should be understood to mean "either or both of" when applied to a list of two or more items, and "at least one of" when applied to a list of two or more items. Unless otherwise indicated, the use of the term "includes" in the specification and in the claims should not be understood as being consistent with the phrase "comprises only." Accordingly, the use of terms such as "comprises" or "comprising," when used in the specification and / or claims, should not be interpreted as suggesting that the aspects of the application are limited to the listed members alone, but rather that the aspects of the application are susceptible to insubstantial variations and / or modifications.

[0302] As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when used in the context of listing items, "or" should be interpreted as the inclusive, i.e., the language "A or B" covers A and / or B. Only the

[0303] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one, or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that the

[0304] In the claims, as well as in the specification above, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of and "consisting essentially of shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. An anion exchange membrane comprising: a porous support membrane; and a silica-based ceramic coating at least a portion of the porous support membrane, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and wherein the silica-based ceramic has an average pore size of less than or equal to 10 nm.

2. An anion exchange membrane comprising: a porous support membrane; and a silica-based ceramic forming a coating on and / or within the porous support membrane, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, wherein the anion exchange membrane has a chloride ion conductivity of greater than or equal to 0.00001 S / cm, and wherein the silica-based ceramic has an average pore size of less than or equal to 10 nm.

3. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, wherein the anion exchange membrane has a water uptake of greater than or equal to 10 wt% and a linear expansion of less than or equal to 10%, wherein the silica-based ceramic has an average pore size of less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

4. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and wherein greater than or equal to 50% of the pore volume of the porous support membrane is filled with the silica-based ceramic, and wherein the silica-based ceramic has an average pore size of less than or equal to 10 nm.

5. An anion exchange membrane comprising: a porous support membrane; and a silica-based ceramic forming a coating on and / or within the porous support membrane, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, wherein the anion exchange membrane has an anion exchange capacity of greater than or equal to 0.01 meq / g, and wherein the silica-based ceramic has an average pore size of less than or equal to 10 nm.

6. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and wherein the quaternary ammonium groups are present in the anion exchange membrane in an amount greater than or equal to 0.01 mmol per gram of the anion exchange membrane, and wherein the average pore size of the silica-based ceramic is less than or equal to 10 nm.

7. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, the silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic, wherein the anion exchange capacity of the anion exchange membrane is greater than or equal to 0.01 meq / g, wherein the average pore size of the silica-based ceramic is less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

8. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, wherein the anion exchange membrane has an anion exchange capacity greater than or equal to 0.01 meq / g and a linear expansion less than or equal to 10%, wherein the average pore size of the silica-based ceramic is less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

9. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, the silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic, wherein the anion selectivity of the anion exchange membrane is greater than or equal to 65%, wherein the average pore size of the silica-based ceramic is less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

10. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, the silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic, wherein the chloride ion conductivity of the anion exchange membrane is greater than or equal to 0.00001 S / cm, wherein the average pore size of the silica-based ceramic is less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

11. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, wherein the anion exchange membrane has a chloride ion conductivity greater than or equal to 0.00001 S / cm and a linear expansion less than or equal to 10%, wherein the silica-based ceramic has an average pore diameter less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

12. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a ceramic based on silicon dioxide coating at least a portion of the porous support membrane, the ceramic based on silicon dioxide comprising Si in an amount greater than or equal to 6 wt% of the ceramic based on silicon dioxide, wherein the anion exchange membrane has a permeate water permeance less than or equal to 100 mL / (hour bar m 2 ), wherein the ceramic based on silicon dioxide has an average pore diameter less than or equal to 10 nm, and wherein the ceramic based on silicon dioxide comprises quaternary ammonium groups covalently bonded to the ceramic based on silicon dioxide.

13. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, the silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic, the silica-based ceramic including pores, wherein the average diameter of the pores of the silica-based ceramic is greater than or equal to 1.1 times as great when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state, wherein the silica-based ceramic has an average pore diameter less than or equal to 10 nm, and wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

14. An anion exchange membrane comprising: a porous support membrane, wherein the porous support membrane is in the form of an open cell structure; and a silica-based ceramic coating at least a portion of the porous support membrane, the silica-based ceramic comprising Si in an amount greater than or equal to 6 wt% of the silica-based ceramic, the silica-based ceramic including pores, wherein the silica-based ceramic has an average pore diameter less than or equal to 10 nm, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and wherein: when the anion exchange membrane is in a dry state, the pores of the silica-based ceramic conform to a model of a small angle scattering spectrum in which intensity (I) is a function of scattering vector q, as follows: where a, cl, and c2 are adjustable parameters and bck is background scattering; and when the anion exchange membrane is in a hydrated state, the pores of the silica-based ceramic conform to a core-shell model of a small angle scattering spectrum in which intensity (I) is a function of scattering vector q, as follows: where R o is the radius of the structural unit (pore), p 溶剂 is the scattering length density of the silica-based ceramic, D f is the fractal dimension, x is the correlation length, G is the standard mathematical gamma function, the proportion is the volume fraction of the structural unit of the silica-based ceramic measured, V c is the volume of the core, V s is the volume of the shell, p c is the scattering length density of the core, p s is the scattering length density of the shell, p 单元 is the scattering length density of the pore, r c is the radius of the core, r s is the radius of the shell, and bck is the background scattering.

15. The anion exchange membrane of any one of claims 1 to 14, wherein the quaternary ammonium groups are directly adjacent to a surface of the porous support membrane.

16. The anion exchange membrane of any one of claims 1-5 and 7-14, wherein the quaternary ammonium groups are present in the anion exchange membrane in an amount greater than or equal to 0.01 mmol per gram of the anion exchange membrane.

17. The anion exchange membrane of any one of claims 1-14, wherein the quaternary ammonium groups are present in the anion exchange membrane in an amount greater than or equal to 0.1 mmol per gram of the anion exchange membrane.

18. The anion exchange membrane of any one of claims 2 and 5, wherein the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic based on an average amount of quaternary ammonium groups across a thickness of the coating.

19. The anion exchange membrane of any one of claims 2 and 5, wherein the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic based on a maximum amount of quaternary ammonium groups across a thickness of the coating.

20. The anion exchange membrane of any one of claims 1-4, 6, and 9-14, wherein the anion exchange capacity of the anion exchange membrane is greater than or equal to 0.01 meq / g.

21. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange capacity of the anion exchange membrane is greater than or equal to 0.1 meq / g.

22. The anion exchange membrane of any one of claims 1-6, 8, and 11, wherein the silica-based ceramic comprises Si in an amount greater than or equal to 6 wt% of the silica-based ceramic.

23. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic comprises Si in an amount greater than or equal to 1.5 mol% of the silica-based ceramic.

24. The anion exchange membrane of any one of claims 1-2, 4-7, 9-10, and 12-14, wherein the linear expansion of the anion exchange membrane is less than or equal to 10%.

25. The anion exchange membrane of any one of claims 1-14, wherein the linear expansion of the anion exchange membrane is less than or equal to 5%.

26. The anion exchange membrane of any one of claims 1-7 and 10-14, wherein the anion permselectivity of the anion exchange membrane is greater than or equal to 65%.

27. The anion exchange membrane of any one of claims 1, 3-9, and 12-14, wherein the chloride conductivity of the anion exchange membrane is greater than or equal to 0.00001 S / cm.

28. The anion exchange membrane of any one of claims 1-10 and 13-14, wherein the anion exchange membrane has a permeate water permeance of less than or equal to 100 mL / (hour-bar-m 2 ).

29. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane has a permeate water permeance of less than or equal to 50 mL / (hr-bar-m2). 2 ) 30. The anion exchange membrane of any one of claims 1-14, wherein there is no intermediate layer between the silica-based ceramic comprising the quaternary ammonium groups and the porous support membrane.

31. The anion exchange membrane according to any one of claims 1 to 12 and 14, wherein the silica-based ceramic comprises pores, and wherein the average diameter of the pores of the silica-based ceramic is greater than or equal to 1.1 times as large when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state.

32. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic comprises pores, and wherein the average diameter of the pores of the silica-based ceramic is less than or equal to 5 times as large when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state.

33. The anion exchange membrane according to any one of claims 1 to 13, wherein the silica-based ceramic comprises pores, and wherein: when the anion exchange membrane is in a dry state, the pores of the silica-based ceramic conform to a model of a small angle scattering spectrum in which intensity (I) is a function of scattering vector q, as follows: where a, cl, and c2 are adjustable parameters and bck is background scattering; and when the anion exchange membrane is in a hydrated state, the pores of the silica-based ceramic conform to a core-shell model of a small angle scattering spectrum in which intensity (I) is a function of scattering vector q, as follows:

34. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic forms a monolayer on the porous support membrane. where R o is the radius of the structural unit (pore), p 溶剂 is the scattering length density of the silica-based ceramic, D f is the fractal dimension, X is the correlation length, G is the standard mathematical gamma function, the proportion is the volume fraction of the structural unit of the silica-based ceramic measured, V c is the volume of the core, V s is the volume of the shell, p c is the scattering length density of the core, p s is the scattering length density of the shell, p 单元 is the scattering length density of the pore, r c is the radius of the core, r s is the radius of the shell, and bck is the background scattering.

35. The anion exchange membrane according to any one of claims 1 to 14, wherein the quaternary ammonium groups are within 1 pm of the surface of the porous support membrane.

36. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic is sol-gel derived.

37. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic is derived from the co-condensation of silicon-containing precursors comprising ammonium groups or moieties comprising leaving groups.

38. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic has a silicon to nitrogen molar ratio greater than or equal to 1 :

1.

39. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic has a silicon to nitrogen molar ratio less than or equal to 120:

1.

40. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic has a silicon to carbon molar ratio greater than or equal to 1 :

100.

41. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic has a silicon to carbon molar ratio greater than or equal to 1 :

50.

42. The anion exchange membrane according to any one of claims 1 to 14, wherein the silica-based ceramic has a silicon to carbon molar ratio less than or equal to 3,000:

1. ​ 43. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a silane comprising nitrogen.

44. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (IV): Where R 1 R 2 and R 3 Independently selected from the arbitrarily substituted C 1-18 Alkoxy and halogen, L is selected from the optionally substituted C 1-18 Alkylene and arylene, and X is a leaving group.

45. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (V): wherein A 1 independently selected from hydrogen, methyl, ethyl, propyl, or butyl, n is greater than or equal to 1 and less than or equal to 18, and X is a leaving group.

46. The anion exchange membrane of any one of claims 1 to 14, wherein X is selected from chlorine, bromine, iodine, tosyl, or triflate.

47. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising (3-chloropropyl)triethoxysilane.

48. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VI): Where R 4 R 5 and R 6 Independently selected from the arbitrarily substituted C 1-18 Alkyl or halogen, where L is selected from the optionally substituted C 1-18 Alkylene or arylene, and R 7 R 8 and R 9 Independently selected from the arbitrarily substituted C 1-18 Alkyl, cycloyl, or aryl.

49. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VII): wherein A 2 is independently selected from hydrogen, methyl, ethyl, propyl, or butyl, n is greater than or equal to 1 and less than or equal to 18, and R 10 , R 11 , and R 12 are independently selected from methyl, ethyl, propyl, butyl, cyclohexyl, or benzyl.

50. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising trimethoxysilylpropyl-N,N,N- trimethylammonium.

51. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VIII): wherein R 13 is independently selected from hydrogen or optionally substituted C 1-18 alkyl.

52. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having the structure of tetraethyl orthosilicate.

53. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VIII), a compound having structure (IV), and water in a molar ratio of 1 :0.01 to 20: 1 to 30.

54. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VIII), a compound having structure (VI), and water in a molar ratio of 1 :0.01 to 10: 1 to 30.

55. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic has an average pore size of less than or equal to 2 nm.

56. The anion exchange membrane of any one of claims 1 to 14, wherein the silica-based ceramic has an average pore size of greater than or equal to 0.25 nm.

57. The anion exchange membrane of any one of claims 1 to 14, wherein the anion exchange membrane has a bulk porosity of greater than or equal to 1%.

58. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane has a volumetric porosity of less than or equal to 70%.

59. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic comprises pores, and wherein the pores of the silica-based ceramic have an aspect ratio of less than or equal to 40:

1.

60. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic comprises pores, and wherein the pores of the silica-based ceramic have an ordered structure.

61. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic comprises pores, and wherein the pores of the silica-based ceramic are substantially spherical.

62. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic comprises pores, and wherein the pores of the silica-based ceramic conform to a spherical model of small angle scattering spectra where chi 2 the value of N is less than or equal to 10, where Chi 2 is the sum of the squared differences in intensity between the spherical model and small angle scattering spectral data, and where N is the number of points of the small angle scattering data points within the range of the spherical model fit.

63. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic has a fractal porous structure.

64. The anion exchange membrane of any one of claims 1-14, wherein the silica-based ceramic comprises pores, and wherein the pores of the silica-based ceramic have a lognormal polydispersity index of pore radii of less than or equal to 0.

8.

65. The anion exchange membrane of any one of claims 1-14, wherein, in the absence of the silica-based ceramic, the porous support membrane comprises pores having an average pore size of greater than or equal to 50 nm.

66. The anion exchange membrane of any one of claims 1-14, wherein, in the absence of the silica-based ceramic, the porous support membrane comprises pores having an average pore size of less than or equal to 50 pm.

67. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane has a cross-sectional thickness of greater than or equal to 3 pm.

68. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane has a cross-sectional thickness of less than or equal to 1,000 pm.

69. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane has a volumetric porosity of greater than or equal to 10%.

70. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane has a volumetric porosity of less than or equal to 99%.

71. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane comprises support components having an average diameter of greater than or equal to 10 nm.

72. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane comprises support components having an average diameter of less than or equal to 50 pm.

73. The anion exchange membrane of any one of claims 1-14, wherein the support components are selected from the group consisting of fibers or threads.

74. The anion exchange membrane of claim 73, wherein the support components comprise strands.

75. The anion exchange membrane of any one of claims 1-2 and 5, wherein the porous support membrane is in the form of an open cell structure.

76. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a nonwoven fabric.

77. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a nonwoven web.

78. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a yarn.

79. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a knitted fabric.

80. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a woven fabric.

81. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a woven web.

82. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of a fibril and node structure.

83. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane is in the form of an open cell foam.

84. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane comprises a polymeric material.

85. The anion exchange membrane of claim 84, wherein the polymeric material is selected from polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyether ether ketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, or a combination or derivative of the foregoing.

86. The anion exchange membrane of claim 85, wherein the cellulose is selected from microfibrillated cellulose, nanofibrillated cellulose, or a combination or derivative of the foregoing.

87. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane comprises a ceramic material.

88. The anion exchange membrane of claim 87, wherein the ceramic material comprises borosilicate glass, silicon dioxide, titanium dioxide, zirconium oxide, aluminum oxide, silicon carbide, silicon nitride, boron nitride, lithium silicate, potassium silicate, tin oxide, iron oxide, or a combination thereof.

89. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane comprises a metal and / or metal alloy.

90. The anion exchange membrane of claim 89, wherein the metal and / or metal alloy comprises iron or steel.

91. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane comprises one or more amphiphilic molecules on a surface of the support membrane.

92. The anion exchange membrane of claim 91, wherein the amphiphilic molecules comprise sodium alkyl sulfate, dialkyl sulfosuccinate, or alkyl trimethyl ammonium halide.

93. The anion exchange membrane of any one of claims 1-4 and 6-14, wherein greater than or equal to 50% of the pore volume of the porous support membrane is filled with the silica-based ceramic.

94. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane comprises an edge seal material comprising a polymeric material.

95. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane comprises an edge seal material selected from the group consisting of silicone, epoxy, polyurethane, acrylic, silicone rubber, poly(styrene-isoprene-styrene), poly(styrene-isobutylene-styrene), polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyether ether ketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, or a combination or derivative of the foregoing.

96. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane has a water uptake of greater than or equal to 1%.

97. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane has a linear expansion of less than or equal to 0.5%.

98. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane has a linear expansion of greater than or equal to 0.01%.

99. The anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane has an anion permselectivity of greater than or equal to 85%.

100. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane has a mechanical burst pressure of greater than or equal to 1.5 N.

101. The anion exchange membrane of any one of claims 1-14, wherein the porous support membrane has a mechanical burst pressure of greater than or equal to 13.79 kiloPascals.

102. The anion exchange membrane of claim 37, wherein the leaving group is selected from the group consisting of chloride, bromide, iodide, tosyl, or triflate.

103. The anion exchange membrane of claim 37, wherein the leaving group is chloride.

104. An electrochemical device comprising the anion exchange membrane of any one of claims 1-14.

105. A reverse osmosis device, nanofiltration device, or ultrafiltration device, wherein the device comprises the anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane is incorporated into the reverse osmosis device, nanofiltration device, or ultrafiltration device.

106. A sorption device comprising the anion exchange membrane of any one of claims 1-14, wherein the anion exchange membrane is incorporated into the sorption device.

107. A method for using the anion exchange membrane of any one of claims 1-14 in an electrochemical application, comprising: contacting the anion exchange membrane with an electrolyte; and and passing an electric current through an electrode in electrical communication with the electrolyte.

108. A method for using the anion exchange membrane of any one of claims 1-14 as an adsorbent material, comprising flowing a fluid through the anion exchange membrane; and adsorbing a component of the fluid.

109. A method for using the anion exchange membrane of any one of claims 1-14 in a separation application, comprising applying a transmembrane pressure to the anion exchange membrane.

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