Structural electrolytes comprising thermoset polymer and related articles, systems, and methods

Abstract

Structural electrolytes comprising thermoset polymer and related articles, systems, and methods are generally described.

Description

[0001] STRUCTURAL ELECTROLYTES COMPRISING THERMOSET POLYMER AND RELATED ARTICLES, SYSTEMS, AND METHODS

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 652,157, filed May 27, 2024, and entitled “Thermoset Structural Polymer Electrolyte,” which is incorporated herein by reference in its entirety for all purposes.

[0004] GOVERNMENT SPONSORSHIP

[0005] This invention was made with government support under N00014-22-1-2630 and N00014-24- 1-2176 awarded by the Office of Naval Research. The government has certain rights in the invention.

[0006] TECHNICAL FIELD

[0007] Structural electrolytes comprising thermoset polymer and related articles, systems, and methods are generally described.

[0008] BACKGROUND

[0009] Electrochemical cells and many other devices include electrolytes that facilitate the transport of ions during operation of the device. Developing materials that fulfil the ion transport function required by such devices while enhancing energy density and specific energy of such devices would be desirable.

[0010] SUMMARY

[0011] Structural electrolytes comprising thermoset polymer and related articles, systems, and methods are generally described. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles. This Summary introduces a selection of concepts in simplified form that are described further below in the Detailed Description.

[0012] Certain aspects relate to compositions. In some embodiments, the composition comprises thermoset polymer; and ionic liquid in combination with the thermoset polymer; wherein: the Young’s modulus of the combination of the thermoset polymer and the ionic liquid is greater than or equal to 100 MPa; and the composition has an ionic conductivity, with respect to at least one monovalent ion and / or at least one divalent ion, of at least IxlO'6S / cm.

[0013] 13991335.1In certain embodiments, the composition comprises thermoset polymer; and ionic liquid; wherein: the thermoset polymer and the ionic liquid are present in bicontinuous phases or a single continuous phase; and less than or equal to 5 vol% of the composition is made up of voids having a maximum cross-sectional dimension of greater than or equal to 100 micrometers.

[0014] Certain aspects are directed to methods of forming compositions. In some embodiments, the method comprises establishing a combination of thermoset polymer precursor and ionic liquid, wherein the combination comprises a low-valency ion, such that the low-valency ion at least partially cures the thermoset polymer precursor to form thermoset polymer, wherein the curing results in bicontinuous phases or a single continuous phase comprising the thermoset polymer and the ionic liquid.

[0015] In certain embodiments, the method comprises establishing a combination of thermoset polymer precursor and ionic liquid, wherein the combination comprises a low-valency ion, such that the low-valency ion at least partially cures the thermoset polymer precursor to form thermoset polymer, wherein the curing results in a combination of thermoset polymer and ionic liquid, the combination having a Young’s modulus of greater than or equal to 100 MPa and an ionic conductivity, with respect to at least one monovalent ion and / or at least one divalent ion, of at least IxlO'6S / cm.

[0016] In some embodiments, compositions are provided in which the composition comprises a structural phase comprising a mixture of epoxy resin, and ionic liquid.

[0017] One aspect of the disclosure herein is a composition comprising

[0018] a. a structural phase comprising a 50% mixture of

[0019] i. an epoxy resin, preferably diglycidyl ether of bisphenol F, most preferably EPON 862 [EPON]; and

[0020] ii. a curing agent, preferably a bisphenol-F epoxy resin and an aromatic amine, most preferably EPIKURE W [W]; and

[0021] iii. an ionic liquid phase comprising

[0022] 1. bis(trifluoromethane)sulfonimide lithium salt [LiTFSI]; and 2. l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI) [IL],

[0023] In one embodiment of the disclosed composition, the composition consists of a highly interpenetrated bicontinuous phase or a single continuous phase.

[0024] In one embodiment of the disclosed composition, the ratio of EPON:W preferably ranges between 2:3 and 1:3, most preferably is a ratio of 79:21.

[0025] 13991335.1In one embodiment, the disclosed composition has an ionic conductivity of at least 0.005xl0'3mS / cm. In one embodiment, the disclosed composition has an ionic conductivity between 0.005xl0'3mS / cm and 7xl0'3mS / cm.

[0026] In one embodiment, the disclosed composition has a modulus of at least 1.65 GPa.

[0027] In one embodiment, the disclosed composition has a Tgbetween 88° C and 97° C.

[0028] One aspect of the disclosure herein is a method of making the disclosed composition, the method comprising:

[0029] a. stirring IL with lithium salt, preferably LiTFSI to produce a lithium solution; b. mixing the epoxy resin (EPON) with the curing agent (W). preferably in a ratio between 2 / 3 or 1 / 3, most preferably at a ratio of 79:21, to produce an epoxy product;

[0030] c. adding the epoxy product with the lithium solution, stirring, and degassing; and d. heating the mixture, preferably a 120° C for 40 min and 150° C for 8 hours. In one embodiment of the disclosed method, the epoxy product and lithium solution are mixed under nitrogen, preferably where [H2O] and [O2] are less than 0.5 ppm.

[0031] This Summary neither identifies key or essential features, nor limits the scope, of the claimed subject matter.

[0032] The following Detailed Description references the accompanying drawings which form a part this application, and which show, by way of illustration, specific example implementations. Other implementations may be made without departing from the scope of the disclosure. Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure.

[0035] 13991335.1FIG. 1 shows a combination of a thermoset polymer and an ionic liquid, in accordance with some embodiments.

[0036] FIG. 2A shows a combination of a thermoset polymer and an ionic liquid, with the combination being a single phase, in accordance with certain embodiments.

[0037] FIG. 2B shows a combination of a thermoset polymer and an ionic liquid, with the combination being in bicontinuous phases, in accordance with some embodiments.

[0038] FIG. 3 shows a composite composition that includes both a combination of a thermoset polymer and an ionic liquid as well as another component, in accordance with some embodiments.

[0039] FIG. 4 is a cross-sectional schematic illustration of a separator, according to certain embodiments.

[0040] FIG. 5 is a cross-sectional schematic illustration of an energy storage device, according to certain embodiments.

[0041] FIG. 6 is a cross-sectional schematic illustration of a layer, according to certain embodiments.

[0042] FIGS. 7A-7D show cross-sectional scanning electron microscope (SEM) imaging of the hand-fractured surfaces of: (A) SPE-1W, (B) SPE-2 / 3W, (C) SPE-1 / 3W and (D) SPE-OW samples. The scale bars in FIGS. 7A-7D indicate a length of 2 micrometers.

[0043] FIGS. 8A-8B show differential scanning calorimetry (DSC) plots of (A) cured and (B) uncured samples (exothermic up).

[0044] FIGS. 9A-9B show Nyquist plots and associated electrochemical impedance spectroscopy (EIS) semicircles of (A) SPE-1W and SPE-2 / 3W and (B) SPE-1 / 3W and SPE-OW.

[0045] DETAILED DESCRIPTION

[0046] Structural electrolytes comprising thermoset polymer and related articles, systems, and methods are generally described. Certain aspects are directed to articles comprising a combination of thermoset polymer and ionic liquid. The combination can, in some embodiments, have a relatively high Young’s modulus and a relatively high ionic conductivity (e.g., with respect to lithium ions or other ions). The presence of both a relatively high Young’s modulus and a relatively high ionic conductivity can, in accordance with certain embodiments, make the combination particularly useful as a structural polymer electrolyte, which provides both high ionic conductivity for ion transport and robust mechanical reinforcement. These electrolytes can lead to enhancements in energy density and specific energy of devices into which they are incorporated, such as energy storage device. In certain embodiments, thermoset 13991335.1polymer and ionic liquid are present in combination in bicontinuous phases or as a single continuous phase, with few or no voids present within the combination. Such arrangements can beneficially result in high Young’s moduli and ionic conductivity. For example, in some such arrangements, the polymer component can provide structural reinforcement while the ionic liquid component can provide high ionic conductivity.

[0047] Also disclosed herein are methods of making combinations of thermoset polymers and ionic liquids. In certain embodiments, a low valency ion can be included in a combination of a thermoset polymer precursor and an ionic liquid. The low valency ion can at least partially cure the thermoset polymer precursor to form a thermoset polymer, which can lead to beneficial material properties of the final combination (e.g., high Young’s modulus and / or high ionic conductivity).

[0048] Generally speaking, Young’s modulus (E) and ionic conductivity (IC) are inversely proportional, such that increases in one property accompany decreases in the other. For example, many structural polymers such as many epoxies have very low IC values (e.g., essentially 0), and many polymer electrolytes (e.g., PEG) have very low Young’s moduli.

[0049] Certain aspects of the present disclosure relate to the surprising discovery that both high Young’s modulus and high ionic conductivity (e.g., for Li+ions or other ions) can be achieved in a combination of polymer and ionic liquid (e.g., present as a single phase or as bicontinuous phases).

[0050] Structural polymers blended with ionic conductive mediums are candidates for structural polymer electrolytes (SPEs). Their properties depend on how these phases are distributed in the SPE, which is dependent on the curing process. According to certain embodiments, it is shown that by reducing the hardener-to-resin ratio, lithium salt can play a role in the curing process, which allows an advantageous intermixing of the solid and liquid phases. Even with no hardener, the SPE yielded, in accordance with certain embodiments, a modulus E = 73MPa (similar to polymer electrolytes blended with the same ratio of ionic liquid). In certain embodiments, at a tailored hardener and Li salt dual curing condition, only a single solid phase was discernible, achieving an ionic conductivity of 7.4xl0'3mS / cm and a modulus of 1.65 GPa.

[0051] Structural polymer electrolytes (SPEs) that combine considerable load-bearing mechanical properties and high ionic conductivities are generally useful for multifunctional energy storage devices, which aim to obtain a net weight and volume savings compared to the use of independent monofunctional materials. This concept is highly attractive for a broad range of applications, such as mobile energy storage in portable electronics, hybrid electric vehicles, and unmanned aerial vehicles, where weight savings is vital. Such devices can include batteries, 13991335.1fuel cells, and supercapacitors; all being improved by multifunctional matrices that can address the conflicting requirements of enabling an ionic path while bearing mechanical load.

[0052] SPEs generally fit into three categories: (1) polymer electrolytes with intrinsic ionic conductivity (e.g. p(VDF-HFP)); (2) a blend of a structural polymer with an ionic medium (e.g. epoxy with ionic liquid and lithium salt) or; (3) a copolymer comprised of monomers of an ionic conductive polymer and monomers of a structural polymer, (e.g. PEDGE, containing PEG and epoxy monomers).

[0053] A large variety of epoxy resin and hardener systems are commercially available, where the resin is a high molecular weight polymer which contains epoxide group(s) and the hardener is a normally an organic molecule containing one or more amine groups, in addition to different solvents, catalysts and fillers. During cure, the amine opens the oxirane ring from epoxy resin forming an aminoalcohol, which further reacts with another oxirane ring. As the curing continues, other epoxy-amine reactions occur, creating crosslinking bonds, as well as other sidereactions that add different linkages to the main epoxy chain. Aside from amines, other organic and inorganic molecules can also initiate these ring-opening polymerization (ROP) reactions, which include ionic liquids and lithium salts, resulting in different epoxy polymers, with different types and degrees of crosslinking.

[0054] As noted above, the present disclosure is generally directed to structural electrolytes comprising thermoset polymer and related articles, systems, and methods. Certain embodiments relate to compositions comprising thermoset polymer and ionic liquid. In accordance with some embodiments, the ionic liquid is in combination with the thermoset polymer. As the phrase is used herein with respect to thermoset polymer and ionic liquid, thermoset polymer and ionic liquid are said to be in “combination” when the outer boundary of the volume occupied by the thermoset polymer component overlaps with the outer boundary of the volume occupied by the ionic liquid component, and the outer boundary of the volume occupied by the ionic liquid component overlaps with the outer boundary of the volume occupied by the thermoset polymer component. Such arrangements might be observed, for example, when the thermoset polymer and ionic liquid components are mixed. The “combination” form factor is in contrast to form factors in which the ionic liquid is in one layer and the thermoset polymer is in another layer that does not overlap volumetrically with the ionic liquid layer (and such arrangements of layers would not be said to form a “combination” of ionic liquid and thermoset polymer).

[0055] One example of a combination of ionic liquid and thermoset polymer is shown in FIG. 1. In FIG. 1, combination 100 comprises thermoset polymer 102 (gray phase) and ionic liquid 104 (white phase). (The cube shown in black lines in FIG. 1 is included only to indicate that the 13991335.1drawing in FIG. 1 is a three-dimensional drawing, and it is not part of the combination itself.) The combination of ionic liquid and thermoset polymer can form, in some embodiments, a structural phase.

[0056] In some embodiments, the ionic liquid within the composition (e.g., the ionic liquid within the combination of ionic liquid and thermoset polymer) may be a single type of ionic liquid. In other embodiments, the ionic liquid within the composition (e.g., the ionic liquid within the combination of ionic liquid and thermoset polymer) may include a plurality of types of ionic liquids. Similarly, in some embodiments, the thermoset polymer within the composition (e.g., the thermoset polymer within the combination of ionic liquid and thermoset polymer) may be a single type of thermoset polymer. In other embodiments, the thermoset polymer within the composition (e.g., the thermoset polymer within the combination of ionic liquid and thermoset polymer) may include a plurality of types of thermoset polymers.

[0057] The thermoset polymer and ionic liquid combination may, in some embodiments, be further combined with materials other than thermoset polymer and ionic liquid, such as nanotubes, nanofibers, microfibers, or other structures. For example, in some embodiments, the compositions described herein may comprise both the combination of ionic liquid and thermoset polymer as well as other components. In instances where this is the case, the physical properties (e.g., the Young’s modulus and the ionic conductivity) of the combination of the ionic liquid and thermoset polymer are to be measured in a way such that the contributions from materials other than thermoset polymer and ionic liquid are not included. Young’s moduli of such combinations can be determined without including the contributions of other materials, for example, using nanoindentation. Ionic conductivity of such combinations can be determined without including the contributions of other materials, for example, by performing electrochemical impedance spectroscopy on just the combination of the thermoset polymer and ionic liquid.

[0058] In some embodiments, the combination of thermoset polymer and ionic liquid exists in an advantageous phase arrangement. In certain embodiments, the combination of thermoset polymer and ionic liquid is present as a single continuous phase. One example of such an arrangement is shown in FIG. 2A, in which combination 200 includes a single continuous phase 202 that is a mixture of ionic liquid and thermoset polymer. The continuous phase can be arranged, in accordance with certain embodiments, such that ions can be transported from one boundary of the continuous phase to an opposing boundary of the continuous phase. For example, in certain embodiments in which the combination of the ionic liquid and the thermoset polymer are in the form of (or are part of a composition that is in the form of) a layer, the

[0059] 13991335.1continuous phase can be arranged, in accordance with certain embodiments, such that ions can be transported through the entire thickness of the layer.

[0060] In some embodiments, the combination of thermoset polymer and ionic liquid is present as bicontinuous phases. The term “bicontinuous phases” is given its normal meaning in the art and refers to an arrangement in which a first interconnected phase and a second interconnected phase are present, and the volumes defined by the exterior boundaries of the first and second interconnected phases overlap with each other. Combinations of ionic liquids and thermoset polymers are present as bicontinuous phases when ionic liquid is present as a first interconnected phase and thermoset polymer is present as a second interconnected phase, and the volumes defined by the exterior boundaries of the first interconnected phase and the second interconnected phase overlap with each other. One example of such an arrangement is shown in FIG. 2B, in which combination 220 includes a first interconnected phase 222 (shown in white) and a second interconnected phase 224 (shown in gray). While separate areas of interconnected phase 222 appear in the cross-section shown in FIG. 2B, those separate areas are connected by regions of phase 222 that lie outside the plane of FIG. 2B (e.g., into and out of the page), such that a single, interconnected phase 222 is present. In some embodiments, interconnected phase 222 can be an interconnected phase of ionic liquid (e.g., one ionic liquid or more than one ionic liquid), and interconnected phase 224 can be an interconnected phase of thermoset polymer (e.g., a single type of thermoset polymer or more than one thermoset polymers). In some embodiments, the thermoset polymer can provide structural support (e.g., leading to a relatively high Young’s modulus), and the ionic liquid can provide a pathway for the conduction of ions (e.g., leading to a relatively high ionic conductivity). As used herein, the outer boundaries of a particular phase or component are defined by the three-dimensional convex hull of that phase or component (i.e., the smallest convex shape that encloses all points of the phase or component). Accordingly, the outer boundaries of a phase or component do not follow the contours of pores or other interior deviations from the three-dimensional convex hull of that phase or component.

[0061] In some embodiments, the composition and / or combination of ionic liquid the thermoset polymer can comprise (or can consist of) highly interpenetrated bicontinuous phases. For example, in some embodiments, at least 50 vol%, at least 75 vol%, at least 90 vol%, at least 95 vol%, at least 98 vol%, at least 99 vol%, at least 99.9 vol%, or more (e.g., 100 vol%) of the ionic liquid of the combination lies within the outer boundaries of the thermoset polymer of the combination. In some embodiments, at least 50 vol%, at least 75 vol%, at least 90 vol%, at least 95 vol%, at least 98 vol%, at least 99 vol%, at least 99.9 vol%, or more (e.g., 100 vol%) of the thermoset polymer of the combination lies within the outer boundaries of the ionic liquid of the 13991335.1combination. The bicontinuous phases can be arranged, in accordance with certain embodiments, such that ions can be transported from one boundary of the bicontinuous phases to an opposing boundary of the bicontinuous phases (e.g., via the continuous ionic liquid phase). For example, in certain embodiments in which the combination of the ionic liquid and the thermoset polymer are in the form of (or are part of a composition that is in the form of) a layer, the bicontinuous phases can be arranged, in accordance with certain embodiments, such that ions can be transported through the entire thickness of the layer.

[0062] To determine the type of phase present within a given combination of ionic liquid and thermoset polymer, one would analyze cross-sectional images of the combination of the ionic liquid and thermoset polymer produced by a scanning electron microscope. In some such embodiments, the determination of the phases is made at a magnification of (or of no more than) l,000,000x.

[0063] In accordance with certain embodiments, the use of combinations of ionic liquid and thermoset polymer that are in the form of bicontinuous phases or a single continuous phase can be advantageous for a variety of reasons. For example, the combination having bicontinuous phases or a single continuous phase may result in properties that are substantially different from the properties of the individual components of the combination. This can lead, for example, to a combination having both a relatively high Young’s modulus as well as a relatively high ionic conductivity (e.g., for at least one low-valency ion, such as Li+).

[0064] In some embodiments, the combination of thermoset polymer and the ionic liquid can have a relatively high Young’s modulus. High Young’s modulus can make the combination suitable for use as a structural material (e.g., in the separator of a battery or capacitor, in a membrane, or in other articles). According to some embodiments, the Young’s modulus of the combination is greater than or equal to 100 MPa, greater than or equal to 500 MPa, greater than or equal to 700 MPa, greater than or equal to 1 GPa, greater than or equal to 1.65 GPa, or greater than or equal to 5 GPa. According to some embodiments, the Young’s modulus of the combination is less than or equal to 10 GPa, less than or equal to 5 GPa, or less than or equal to 2 GPa. Combinations of these ranges are possible (e.g., greater than or equal to 100 MPa and less than or equal to 10 GPa).

[0065] In some embodiments, the composition that comprises the combination of thermoset polymer and the ionic liquid (which can also include other components, such as carbon nanotubes) can have a relatively high Young’s modulus. According to some embodiments, the Young’s modulus of the composition that comprises the combination is greater than or equal to 100 MPa, greater than or equal to 500 MPa, or greater than or equal to 700 MPa, greater than or 13991335.1equal to 1 GPa, greater than or equal to 1.65 GPa, or greater than or equal to 5 GPa. According to some embodiments, the Young’s modulus of the combination is less than or equal to 10 GPa, less than or equal to 5 GPa, or less than or equal to 2 GPa. Combinations of these ranges are possible (e.g., greater than or equal to 100 MPa and less than or equal to 10 GPa).

[0066] In some embodiments, the combination of the thermoset polymer and the ionic liquid has a relatively high ionic conductivity. High ionic conductivity can make the combination suitable for use as an ion-transporting material (e.g., in the separator of a battery or capacitor, in a membrane, or in other articles).

[0067] According to some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of greater than or equal to IxlO'6S / cm, greater than or equal to 5xl0'6S / cm, greater than or equal to IxlO'5S / cm, greater than or equal to 5x1 O'5S / cm, greater than or equal to IxlO-4S / cm, greater than or equal to 4x1 O'4S / cm, greater than or equal to IxlO'3S / cm, greater than or equal to 5xl0'3S / cm, greater than or equal to IxlO'2S / cm, or greater than or equal to 5xl0'2S / cm. According to some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of less than or equal to IxlO'1S / cm, less than or equal to 5xl0'2S / cm, less than or equal to IxlO'2S / cm, less than or equal to IxlO'3S / cm, less than or equal to 8xl0'4S / cm, less than or equal to bxlO"4S / cm, or less than or equal to 5xl0'4S / cm. Combinations of these ranges are possible (e.g., greater than or equal to IxlO'6S / cm and less than or equal to IxlO'1S / cm, or greater than or equal to IxlO'6S / cm and less than or equal to IxlO'3S / cm). In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of at least 0.005xl0'3mS / cm. In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of between 0.005xl0'3mS / cm and 7xl0'3mS / cm.

[0068] According to some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of greater than or equal to IxlO'6S / cm, greater than or equal to 5xl0'6S / cm, greater than or equal to IxlO'5S / cm, greater than or equal to 5xl0'5S / cm, greater than or equal to IxlO'4S / cm, greater than or equal to 4x1 O'4S / cm, greater than or equal to IxlO'3S / cm, greater than or equal to 5xl0'3S / cm, greater than or equal to IxlO'2S / cm, or greater than or 13991335.1equal to 5xl0'2S / cm. According to some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of less than or equal to IxlO'1S / cm, less than or equal to 5xl0'2S / cm, less than or equal to IxlO'2S / cm, less than or equal to IxlO'3S / cm, less than or equal to 8xl0'4S / cm, less than or equal to bxlO-4S / cm, or less than or equal to SxlO'4S / cm. Combinations of these ranges are possible (e.g., greater than or equal to IxlO'6S / cm and less than or equal to IxlO'1S / cm, or greater than or equal to IxlO'6S / cm and less than or equal to IxlO'3S / cm). In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of at least 0.005xl0'3mS / cm. In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of between 0.005xl0'3mS / cm and 7xl0'3mS / cm.

[0069] According to some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions (e.g., Li+), of greater than or equal to IxlO'6S / cm, greater than or equal to 5x1 O'6S / cm, greater than or equal to IxlO'5S / cm, greater than or equal to 5xl0'5S / cm, greater than or equal to IxlO'4S / cm, greater than or equal to 4x1 O'4S / cm, greater than or equal to IxlO'3S / cm, greater than or equal to 5x1 O'3S / cm, greater than or equal to IxlO'2S / cm, or greater than or equal to 5xl0'2S / cm. According to some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions (e.g., Li+), of less than or equal to IxlO'1S / cm, less than or equal to 5xl0'2S / cm, less than or equal to IxlO'2S / cm, less than or equal to IxlO'3S / cm, less than or equal to SxlO"4S / cm, less than or equal to 6xl0'4S / cm, or less than or equal to 5xl0'4S / cm. Combinations of these ranges are possible (e.g., greater than or equal to IxlO'6S / cm and less than or equal to IxlO'1S / cm, or greater than or equal to IxlO'6S / cm and less than or equal to IxlO'3S / cm). In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions (e.g., Li+), of at least 0.005xl0'3mS / cm. In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity, with respect to lithium ions (e.g., Li+), of between 0.005xl0'3mS / cm and 7xl0'3mS / cm.).

[0070] According to some embodiments, the composition within which the combination of the ionic liquid and the thermoset polymer is present (which may include components other than the ionic liquid and the thermoset polymer) has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), 13991335.1of greater than or equal to IxlO'6S / cm, greater than or equal to 5x1 O'6S / cm, greater than or equal to IxlO'5S / cm, greater than or equal to 5x1 O'5S / cm, greater than or equal to lx IO"4S / cm, greater than or equal to 4x1 O'4S / cm, greater than or equal to IxlO'3S / cm, greater than or equal to 5xl0'3S / cm, greater than or equal to IxlO'2S / cm, or greater than or equal to 5xl0'2S / cm. According to some embodiments, the composition within which the combination of the ionic liquid and the thermoset polymer is present has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of less than or equal to IxlO'1S / cm, less than or equal to 5xl0'2S / cm, less than or equal to IxlO'2S / cm, less than or equal to IxlO'3S / cm, less than or equal to 8xl0'4S / cm, less than or equal to 6xl0'4S / cm, or less than or equal to 5xl0'4S / cm. Combinations of these ranges are possible (e.g., greater than or equal to IxlO'6S / cm and less than or equal to IxlO'1S / cm, or greater than or equal to IxlO'6S / cm and less than or equal to IxlO'3S / cm). In some embodiments, the composition has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of at least 0.005xl0'3mS / cm. In some embodiments, the composition has an ionic conductivity, with respect to at least one monovalent ion (e.g., monovalent cation) and / or at least one divalent ion (e.g., divalent cation), of between 0.005xl0'3mS / cm and 7xl0'3mS / cm.

[0071] According to some embodiments, the composition within which the combination of the ionic liquid and the thermoset polymer is present (which may include components other than the ionic liquid and the thermoset polymer) has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of greater than or equal to IxlO'6S / cm, greater than or equal to 5xl0'6S / cm, greater than or equal to IxlO'5S / cm, greater than or equal to 5x1 O'5S / cm, greater than or equal to IxlO'4S / cm, greater than or equal to 4x1 O'4S / cm, greater than or equal to IxlO'3S / cm, greater than or equal to 5xl0'3S / cm, greater than or equal to IxlO'2S / cm, or greater than or equal to 5xl0'2S / cm. According to some embodiments, the composition within which the combination of the ionic liquid and the thermoset polymer is present has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of less than or equal to IxlO'1S / cm, less than or equal to 5xl0'2S / cm, less than or equal to IxlO'2S / cm, less than or equal to IxlO'3S / cm, less than or equal to 8xl0'4S / cm, less than or equal to 6xl0'4S / cm, or less than or equal to SxlO"4S / cm. Combinations of these ranges are possible (e.g., greater than or equal to IxlO'6S / cm and less than or equal to IxlO'1S / cm, or greater than or equal to IxlO'6S / cm and less than or equal to IxlO'3S / cm). In some embodiments, the composition has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of at least 0.005xl0'3mS / cm. In some 13991335.1embodiments, the composition has an ionic conductivity, with respect to lithium ions, sodium ions, magnesium ions, and / or potassium ions, of between 0.005xl0'3mS / cm and 7xl0'3mS / cm.

[0072] According to some embodiments, the composition within which the combination of the ionic liquid and the thermoset polymer is present (which may include components other than the ionic liquid and the thermoset polymer) has an ionic conductivity, with respect to lithium ions (e.g., Li+), of greater than or equal to IxlO'6S / cm, greater than or equal to 5xl0'6S / cm, greater than or equal to IxlO'5S / cm, greater than or equal to 5x1 O'5S / cm, greater than or equal to IxlO'4S / cm, greater than or equal to 4x1 O'4S / cm, greater than or equal to IxlO'3S / cm, greater than or equal to 5x1 O'3S / cm, greater than or equal to IxlO'2S / cm, or greater than or equal to 5x1 O'2S / cm. According to some embodiments, the composition within which the combination of the ionic liquid and the thermoset polymer is present has an ionic conductivity, with respect to lithium ions (e.g., Li+), of less than or equal to IxlO'1S / cm, less than or equal to 5xl0'2S / cm, less than or equal to IxlO'2S / cm, less than or equal to IxlO'3S / cm, less than or equal to 8xl0'4S / cm, less than or equal to 6xl0'4S / cm, or less than or equal to SxlO"4S / cm. Combinations of these ranges are possible (e.g., greater than or equal to IxlO'6S / cm and less than or equal to IxlO'1S / cm, or greater than or equal to IxlO'6S / cm and less than or equal to IxlO'3S / cm). In some embodiments, the composition has an ionic conductivity, with respect to lithium ions (e.g., Li+), of at least 0.005xl0'3mS / cm. In some embodiments, the composition has an ionic conductivity, with respect to lithium ions (e.g., Li+), of between 0.005xl0'3mS / cm and 7xl0'3mS / cm.

[0073] In some embodiments, the composition has an ionic conductivity of at least 0.005x1 O'3mS / cm. In some embodiments, the composition has an ionic conductivity between 0.005xl0'3mS / cm and 7x1 O'3mS / cm.

[0074] In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity of at least 0.005xl0'3mS / cm. In some embodiments, the combination of the ionic liquid and the thermoset polymer has an ionic conductivity between 0.005x1 O'3mS / cm and 7xl0'3mS / cm.

[0075] In certain embodiments, the composition and / or the combination of the ionic liquid and thermoset polymer can have a glass transition temperature (Tg) that is relatively low. For example, in some embodiments, the composition and / or the combination of the ionic liquid and thermoset polymer can have a glass transition temperature that is less than or equal to 97°C. In some embodiments, the composition and / or the combination of the ionic liquid and thermoset polymer can have a glass transition temperature between 88°C and 97°C.

[0076] 13991335.1In certain embodiments the combination of the ionic liquid and the thermoset polymer and / or a composition comprising the combination of the ionic liquid and the thermoset polymer may have a relatively small number of large voids. The absence of large voids can, in accordance with certain embodiments, lead to enhancements in structural stability of the combination and / or composition while maintaining high ionic conductivity. In this context, the term “void” is used to refer to any volume that is occupied by (1) a liquid that is not an ionic liquid or a thermoset polymer, (2) any gas, or (3) vacuum. As non-limiting examples, a volume occupied by an aqueous solution of lithium ions that is not in the form of an ionic liquid would be considered a void. Similarly, a volume occupied by nitrogen gas would be considered a void. As another example, a volume occupied by vacuum would be considered a void. A volume occupied by a solid (e.g., a carbon nanotube) would not be considered a void for the purposes of the determinations described herein. Voids may be open-celled or closed-celled.

[0077] Sizes of voids can be characterized by their maximum cross-sectional dimensions. As used herein, the “maximum cross-sectional dimension” of a void is the largest dimension that passes through a first boundary of the void, through the geometric center of the void, and to a second boundary of the void that is opposite the first boundary of the void.

[0078] In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the composition comprising the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 100 micrometers. In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the composition comprising the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 10 micrometers. In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the composition comprising the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 1 micrometer. In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the composition comprising the ionic liquid

[0079] 13991335.1and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 100 nanometers.

[0080] In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the combination of the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 100 micrometers. In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the combination of the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 10 micrometers. In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the combination of the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 1 micrometer. In certain embodiments, less than or equal to 5 vol% (or less than or equal to 2 vol%, less than or equal to 1 vol%, less than or equal to 0.5 vol%, less than or equal to 0.1 vol%, less than or equal to 0.05 vol%, less than or equal to 0.01 vol%, or less) of the combination of the ionic liquid and the thermoset polymer is made up of voids having a maximum cross-sectional dimension of greater than or equal to 100 nanometers.

[0081] A variety of thermoset polymers may be used, in accordance with certain embodiments. In some embodiments, the thermoset polymer comprises an epoxy (e.g., epoxy resin). Nonlimiting examples of epoxies include glycidyl epoxy, non-glycidyl epoxy, aliphatic epoxy, cycloaliphatic epoxy, bisphenol epoxy, and novolac epoxy. Other examples of thermoset polymers that can be used include polyurethane resins, phenolic resins, melamine formaldehyde resins, bakelite resins, polyimide resins, cyanide ester resins, and unsaturated polyester resins. As noted above, the thermoset polymer component of the compositions and combinations described herein may include more than one type of thermoset polymer. In certain embodiments, it can be particularly advantageous to use a bisphenol F epoxy resin (e.g., EPON™ 862) as the epoxy resin.

[0082] Various embodiments may also make use of a variety of ionic liquids. Ionic liquids are salts that exist in a liquid state, typically at or below room temperature. In some embodiments, the ionic liquids that are used herein are in a liquid state at 25°C and 1 atm of pressure. The 13991335.1ionic liquid can include a variety of cations, such as l-ethyl-3-methylimidazolium (EMIM), 1-butyl-3-methylimidazolium (BMIM), l-hexyl-3-methylimidazolium (HMIM), n-butyl-n-methylpyrrolidinium (PYRu), 1 -methyl- 1-propylpyrrolidinium (PYR ), 1 -butyl- 1-methylpiperidinium (PIPu), choline (Ch), and trihexyl(tetradecyl)phosphonium (Peeeu). The ionic liquid can also include a variety of anions, such as bis(trifluoromethylsulfonyl)imide (TFSI), tetrafluoroborate (BF4), bis(fluorosulfonyl)imide (FSI), hexafluorophosphate (PFe), chloride (Cl), lactate (La), and isoleucine (He). Non-limiting examples of ionic liquids that may be used in the articles and methods described herein include l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), l-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4), l-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI), l-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4), l-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PFe), l-hexyl-3-methylimidazolium chloride (HMIM-C1), n-butyl-n-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYRM-TFSI), 1 -methyl- 1-propylpyrrolidinium bis(fluorosulfonyl)imide (PYR13-FSI), 1 -butyl- 1-methylpiperidinium bis(trifluoromethylsulfonyl)imide (PIPM-TFSI), choline lactate (Ch-La), choline isoleucine (Chile), trihexyl(tetradecyl)phosphonium chloride (Peeeu-Cl), and trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide (Peeeu-TFSI). In certain embodiments, it can be particularly advantageous to use EMIM-TFSI as the ionic liquid.

[0083] In some embodiments, the ionic liquid may comprise a low-valency cation (e.g., dissolved within the ionic liquid). For example, a low-valency cation may be solubilized within the ionic liquid. In instances in which ions or other materials are present within the ionic liquid (e.g., supplemental low-valency ions solubilized or otherwise present within the ionic liquid), such materials are considered to be part of the ionic liquid for the purposes of calculating the parameters and properties (e.g., ionic conductivities, Young’s modulus, etc.) of the ionic liquids, the combinations of the ionic liquids and the thermoset polymers, and the compositions comprising the ionic liquid described herein.

[0084] As used herein, a “low-valency cation” is a cation having a valency of +1 or +2. Nonlimiting examples of low-valency cations include lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, and radium. In certain embodiments, it can be particularly advantageous to include lithium, sodium, potassium, beryllium, magnesium, and / or calcium ions in the ionic liquid. In certain embodiments, it can be particularly advantageous to include lithium, sodium, potassium, and / or magnesium ions in the ionic liquid. In certain embodiments, it can be particularly advantageous to include lithium ions in the ionic liquid. In certain embodiments, the ionic liquid includes low-valency cations that 13991335.1are of the same type as the cations the composition or combination is configured to conduct. For example, in some embodiments in which the composition or combination is configured to conduct lithium ions, the ionic liquid of the composition or combination comprises lithium ions.

[0085] In certain embodiments, the concentration of the low-valency cation within the ionic liquid can be relatively high. For example, in some embodiments, the concentration of the low-valency cation within the ionic liquid can be greater than or equal to 0.01 mol / L, greater than or equal to 0.025 mol / L, greater than or equal to 0.05 mol / L, greater than or equal to 0.1 mol / L, greater than or equal to 0.25 mol / L, greater than or equal to 0.5 mol / L, greater than or equal to 0.75 mol / L, greater than or equal to 1 mol / L, greater than or equal to 2.5 mol / L, greater than or equal to 5 mol / L, or greater than or equal to 10 mol / L. In some embodiments, the concentration of the low- valency cation within the ionic liquid can be less than or equal to 30 mol / L, less than or equal to 20 mol / L, less than or equal to 10 mol / L, less than or equal to 5 mol / L, less than or equal to 4 mol / L, less than or equal to 3 mol / L, less than or equal to 2 mol / L, less than or equal to 1.5 mol / L, less than or equal to 1 mol / L, less than or equal to 0.5 mol / L, or less.

[0086] Combinations of these ranges are also possible (e.g., greater than or equal to 0.1 mol / L and less than or equal to 2 mol / L).

[0087] Low- valency cations can be added to the ionic liquid, for example, by dissolving a salt within the ionic liquid. Any of a variety of suitable anions can be part of the salt that contains the low-valency cations, such as bis(trifluoromethylsulfonyl)imide (TFSI), tetrafluoroborate (BF4), bis(fluorosulfonyl)imide (FSI), hexafluorophosphate (PFe), chloride (Cl), lactate (La), isoleucine (He), perchlorate (CIO4), and sulfate (SO4). Non-limiting examples of suitable salts that can be used include, but are not limited to, LiPFe, LiTFSI, LiCICU, LiFSI, LiCl, Li2SO4, NaPF6, NaTFSI, NaCICL, NaFSI, NaCl, Na2SO4, Mg(PF6)2, Mg(TFSI)2, Mg(C104)2, Mg(FSI)2, MgCl2, MgSO4, Ca(PF6)2, Ca(TFSI)2, Ca(C104)2, Ca(FSI)2, CaCl2, and CaSO4. In certain embodiments, it can be particularly advantageous to use LiTFSI to add lithium ions to the ionic liquid.

[0088] The compositions comprising the ionic liquid and thermoset polymer can have relatively large volume, in some embodiments. For example, in some embodiments, the composition comprising the ionic liquid and thermoset polymer can have a volume of greater than or equal to 10,000 cubic micrometers; greater than or equal to 100,000 cubic micrometers; greater than or equal to 0.001 cubic millimeters; greater than or equal to 0.01 cubic millimeters; greater than or equal to 0.1 cubic millimeters; greater than or equal to 1 cubic millimeter; greater than or equal to 10 cubic millimeters; greater than or equal to 100 cubic millimeters; greater than or equal to 1 cubic centimeter; greater than or equal to 10 cubic centimeters; greater than or equal to 100 13991335.1cubic centimeters; greater than or equal to 1,000 cubic centimeters; greater than or equal to 10,000 cubic centimeters; greater than or equal to 0.1 cubic meters; greater than or equal to 1 cubic meter; or more. In some embodiments, the composition comprising the ionic liquid and thermoset polymer can have a volume of less than or equal to 1,000 cubic meters, less than or equal to 100 cubic meters, less than or equal to 10 cubic meters, or less. Combinations of these ranges are also possible (e.g., greater than or equal to 10,000 cubic micrometers and less than or equal to 1,000 cubic meters).

[0089] The combination of the ionic liquid and the thermoset polymer can have relatively large volume, in some embodiments. For example, in some embodiments, the combination of the ionic liquid and the thermoset polymer has a volume of greater than or equal to 10,000 cubic micrometers; greater than or equal to 100,000 cubic micrometers; greater than or equal to 0.001 cubic millimeters; greater than or equal to 0.01 cubic millimeters; greater than or equal to 0.1 cubic millimeters; greater than or equal to 1 cubic millimeter; greater than or equal to 10 cubic millimeters; greater than or equal to 100 cubic millimeters; greater than or equal to 1 cubic centimeter; greater than or equal to 10 cubic centimeters; greater than or equal to 100 cubic centimeters; greater than or equal to 1,000 cubic centimeters; greater than or equal to 10,000 cubic centimeters; greater than or equal to 0.1 cubic meters; greater than or equal to 1 cubic meter; or more. In some embodiments, the combination of the ionic liquid and the thermoset polymer has a volume of less than or equal to 1,000 cubic meters, less than or equal to 100 cubic meters, less than or equal to 10 cubic meters, or less. Combinations of these ranges are also possible (e.g., greater than or equal to 10,000 cubic micrometers and less than or equal to 1,000 cubic meters).

[0090] In certain embodiments, the composition comprising ionic liquid and thermoset polymer is arranged such that the ionic liquid remains associated with the thermoset polymer when the composition is handled. This behavior is in contrast to, for example, separators in which liquid electrolyte fills pores of a solid separator but is released from the separator when the separator is handled. In some embodiments, when the composition comprising the ionic liquid and the thermoset polymer is lifted off of a glass (e.g., fused quartz) surface, at least 90 vol%, at least 95 vol%, at least 99 vol%, at least 99.9 vol%, at least 99.99 vol%, at least 99.999 vol%, at least 99.9999 vol%, or 100 vol% of the ionic liquid remains within the composition and associated with the thermoset polymer. In some embodiments, when the composition comprising the ionic liquid and the thermoset polymer is lifted off of a glass (e.g., fused quartz) surface, at least 90 vol%, at least 95 vol%, at least 99 vol%, at least 99.9 vol%, at least 99.99 vol%, at least 99.999 vol%, at least 99.9999 vol%, or 100 vol% of the ionic liquid remains in a phase of bicontinuous 13991335.1phases with the thermoset polymer. In some embodiments, when the composition comprising the ionic liquid and the thermoset polymer is lifted off of a glass (e.g., fused quartz) surface, at least 90 vol%, at least 95 vol%, at least 99 vol%, at least 99.9 vol%, at least 99.99 vol%, at least 99.999 vol%, at least 99.9999 vol%, or 100 vol% of the ionic liquid remains in a single continuous phase with the thermoset polymer.

[0091] In certain embodiments, the ionic liquid and the thermoset polymer make up a relatively large percentage of the volume of the composition comprising the ionic liquid and the thermoset polymer. For example, in some embodiments, at least 25 vol%, at least 50 vol%, at least 75 vol%, at least 90 vol%, at least 95 vol%, at least 98 vol%, at least 99 vol%, at least 99.9 vol%, at least 99.99 vol%, at least 99.999 vol%, or more (e.g., 100 vol%) of the composition comprising ionic liquid and thermoset polymer are made up of ionic liquid or thermoset polymer.

[0092] It should be understood that the compositions described herein can include components other than ionic liquid and thermoset polymer. In accordance with certain embodiments, any of a variety of components may be added (e.g., mixed with before or during a curing process) to the components that ultimately form the composition. Examples of components that can be added include, but are not limited to, fillers, colorants, flame retardants, processing aids, and lubricants. In another set of embodiments, the components are particles, rods, spheres, wires, tubes, or the like. In some embodiments, the additional components can be microscale components (e.g., microparticles, microrods, microspheres, microwires, and / or microtubes). In some embodiments, the additional components can be nanoscale components (e.g., nanoparticles, nanorods, nanospheres, nanowires, and / or nanotubes). In some embodiments, the combination and the additional component(s) may form a composite. For example, as shown in FIG. 3, composition 300 is in the form of a composite comprising combination 302 of ionic liquid and thermoset polymer as well as nanotubes 304. In some embodiments, the component included within the composition that is not ionic liquid or thermoset polymer comprises nanotubes (e.g., single-walled nanotubes or multi-walled nanotubes such as double-walled nanotubes). Nonlimiting examples of nanotubes include carbon nanotubes and boron nitride nanotubes.

[0093] Components other than ionic liquid and thermoset polymer may be present in any of a variety of suitable ratios. In some embodiments, amount of components in the composition that are not ionic liquid or thermoset polymer is less than or equal to 10 wt%, less than or equal to 5 wt%, less than or equal to 1 wt%, less than or equal to 0.5 wt%, or less than or equal to 0.1 wt% of the total weight of the composition. In some embodiments, amount of components in the composition that are not ionic liquid or thermoset polymer is greater than or equal to 0.01 wt%, greater than or equal to 0.05 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.5 13991335.1wt%, or greater than or equal to 1 wt% of the total weight of the composition. Combinations of these ranges are also possible (e.g., greater than or equal to 0.01 wt% and less than or equal to 10 wt%).

[0094] The compositions and / or combinations of ionic liquid and thermoset polymer described herein can be used in a variety of applications. Non-limiting examples include supercapacitors (e.g., structural supercapacitors, electric double layer capacitors), pseudocapacitors, hybrid capacitors, batteries (e.g., structural batteries, lithium-ion batteries, lithium-metal batteries), and ion-selective membranes (e.g., ultra-high Li+selective membranes, blue energy storage membranes). In some embodiments, the compositions and / or combinations of ionic liquid and thermoset polymer described herein can be used in transistors, ionic semiconductors, photovoltaic cells, sensors, thermoelectric devices, capacitors, and / or iontronic devices.

[0095] The compositions and / or combinations of ionic liquid and thermoset polymer can be used to conduct a variety of ions, including sodium ions, potassium ions, magnesium ions, and lithium ions, among others described herein. In some embodiments, it can be particularly advantageous to use the compositions and / or combinations of ionic liquid and thermoset polymer described herein to conduct lithium ions.

[0096] In some embodiments, the compositions and / or combinations of ionic liquid and thermoset polymer can be or can be part of a membrane. In some embodiments, the membrane can be, in some embodiments, part of a separator. The separator can be used to selectively transport one or more types of ions through the thickness of the membrane, in accordance with certain embodiments. One example of such a separator is shown in FIG. 4. In FIG. 4, separator 400 comprises membrane 402, retentate side 404, and permeate side 406. Fluid can be transported into separator 400 via input 408. In some embodiments, ions (e.g., lithium ions or other ions) can be selectively transported through membrane 402, from retentate side 404 to permeate side 406. In some embodiments, ouput 410, which includes ions that were selectively transported through membrane 402 (and which may be enriched with such ions relative to input 408 and / or output 412), can be removed from permeate side 406. In some embodiments, output 412, which is lean in the ions that were selectively transported through membrane 402 relative to input 408, can be removed from retentate side 404. In some embodiments, the ions that are selectively transported through membrane 402 are transported through membrane 402 with a flux that is at least 2 times (or at least 5 times, at least 10 times, or more and / or up to 100 times, up to 1,000 times, up to 10,000 times, up to 100,000 times, or more) higher than the flux of at least one, at least two, or all other ions within input 408.

[0097] 13991335.1In some embodiments, the compositions and / or combinations of ionic liquid and thermoset polymer can be or can be part of a separator of an energy storage device (e.g., a primary battery, a secondary battery, a capacitor, a fuel cell, an electroplating cell, or another type of electrochemical cell). One example of such an energy storage device is shown in FIG. 5. In FIG. 5, energy storage device 500 comprises separator 502, anode 504, and cathode 506. All or part of separator 502 may be made of any of the compositions and / or combinations or ionic liquid and thermoset polymer described herein. Energy storage device may also include housing 508, which contains separator 502, anode 504, and cathode 506. Separator 502 can electronically insulate anode 504 from cathode 506 while also providing sufficient ionic conductivity (e.g., for Li+or any other working ion of energy storage device 500) to allow the energy storage device to be discharged without short circuiting. In cases where energy storage device 500 is rechargeable, separator 502 may also provide sufficient ionic conductivity to allow the energy storage device 500 to be recharged.

[0098] In certain embodiments, the compositions and / or combinations of ionic liquid and thermoset polymer can be in the form of a layer. A “layer” is a form factor having a thickness dimension and two lateral dimensions, with each lateral dimension perpendicular to the thickness dimension and to the other lateral dimension, and in which each lateral dimension has a length that is at least three (3) times the thickness dimension. A layer also has two “major surfaces,” which are surfaces that are defined by the two lateral dimensions. In FIG. 6, for example, layer 600 has thickness dimension 602, first lateral dimension 604, and second lateral dimension 606. Layer 600 also has first major surface 608a and second major surface 608b (hidden from view). In certain embodiments, the layer is arranged such that the length of at least one lateral dimension (or both lateral dimensions) is at least 5 times, at least 10 times, at least 1,000 times, at least 100,000 times, or at least 1,000,000 times the thickness. In certain embodiments, at least one major surface of the layer (or both major surfaces of the layer) have a geometric surface area of at least 0.1 square millimeters, at least 0.5 square millimeters, at least 1 square millimeter, at least 5 square millimeters, at least 10 square millimeters, at least 50 square millimeters, at least 1 square centimeter, at least 5 square centimeters, at least 10 square centimeters, at least 50 square centimeters, at least 100 square centimeters, at least 500 square centimeters, at least 1,000 square centimeters, at least 5,000 square centimeters, at least 1 square meter, at least 5 square meters, at least 10 square meters, at least 50 square meters, at least 100 square meters, or more.

[0099] The layer can be arranged, in accordance with certain embodiments, such that ions can be transported from one boundary of the layer to an opposing boundary of the layer. For

[0100] 13991335.1example, the layer can be arranged, in accordance with certain embodiments, such that ions can be transported from one major surface of the layer (e.g., major surface 608b in FIG. 6), through the thickness of the layer, and to the opposing major surface of the layer (e.g., major surface 608a in FIG. 6).

[0101] In addition to compositions, methods of forming compositions are also disclosed herein. The methods described herein can be used to form any of the compositions described above or elsewhere herein.

[0102] According to some embodiments, the method of forming a composition comprises establishing a combination of thermoset polymer precursor and ionic liquid. The thermoset polymer precursor can comprise a precursor of any of the thermoset polymers described elsewhere herein. In some embodiments, the thermoset polymer precursor comprises an epoxide. As one non-limiting example, the thermoset polymer precursor can be an epoxide, such as bisphenol F diglycidyl ether (BFDGE), which is a precursor of bisphenol F epoxy. Other thermoset polymer precursors that can be used include, but are not limited to, bisphenol A (BPA), bisphenol S (BPS), bisphenol AF (BPAF), and bisphenol E (BPE). The ionic liquid can be any of the ionic liquids described above or elsewhere herein.

[0103] Establishing a combination of the thermoset polymer precursor and the ionic liquid can comprise combining those material in any order. For example, the thermoset polymer precursor can be added to the ionic liquid, the ionic liquid can be added to the thermoset polymer precursor, or the two components can be added to container at the same time.

[0104] In certain embodiments, the combination of thermoset polymer precursor and ionic liquid comprises a low-valency cation (e.g., monovalent cation, divalent cation). The low-valency cation can be any of the low-valency cations mentioned above or elsewhere herein, and it can be sourced from any of the sources mentioned above or elsewhere herein. In some embodiments, the low-valency cation at least partially cures (or substantially completely cures) the thermoset polymer precursor. In accordance with some embodiments, the cured polymer thermoset polymer precursor forms a thermoset polymer (also referred to herein as cured thermoset polymer). Curing the polymer precursor, in some embodiments, may result in the formation of the compositions and / or combinations described above or elsewhere herein. For example, curing the polymer precursor may, in some embodiments, result in the formation of bicontinuous phases of ionic liquid and thermoset polymer or a single continuous phase of ionic liquid and thermoset polymer. The composition and / or combination may have any of the properties (e.g., Young’s modulus, ionic conductivity, etc.) mentioned above or elsewhere herein.

[0105] 13991335.1In some embodiments, during the forming, the thermoset polymer precursor undergoes a chemical reaction with one or more components of the ionic liquid. The chemical reaction may comprise, for example, a ring-opening polymerization reaction. Without wishing to be bound by any particular theory, it is believed that, in accordance with certain embodiments, without hardener, epoxy precursor may crosslink or harden via ring-opening reactions initiated by nucleophiles. It is believed that low-valency ions (e.g., lithium ions) can enhance this process by activating the epoxide ring, but do not themselves form bonds with the resin. It is believed that low-valency ions (e.g., lithium ions) can coordinate to the oxygen atom of the epoxide ring, increasing its electrophilicity and making it more susceptible to nucleophilic attack, which it is believed may lead to partial curing.

[0106] As described and elaborated elsewhere herein, a composition comprising a combination may be at least partially cured in the presence of a low-valency cation. In some embodiments, a curing agent other than the low-valency cation (e.g., a hardener) is also present during the curing (e.g., by including the curing agent in the combination of the ionic liquid and the thermoset polymer precursor). In some such embodiments, the curing agent at least partially cures the thermoset polymer precursor that is within the combination. A variety of curing agents can be used. In some embodiments, the curing agent comprises an aromatic amine. In some embodiments, the curing agent comprises an amine-based curing agent (e.g., Epikure 3274; Epikure 3271; Epikure 3270; Epikure 3223; and / or 4, 4’ -diaminodiphenyl sulfone (DDS)), an anhydride-based curing agent (e.g., hexahydrophthalic anhydride (HHPA), methylhexahydrophthalic anhydride (MHHPA), nadic methyl anhydride (NMA), and / or methyl tetrahydrophthalic anhydride (MTHPA)), and / or an imidazole (e.g., 2-methylimidazole (2-MI), 1 -methylimidazole (1-MI), dicyandiamide (DICY), and / or triethylenetetramine (TETA)). In some embodiments, it can be particularly advantageous to use EPIKURE W as a curing agent. In some embodiments, the method comprises mixing thermoset polymer precursor with a curing agent to make an epoxy product. The epoxy product can then be added to a lithium solution to make a mixture, in certain embodiments. The lithium solution can be made, for example, by adding a lithium salt (e.g., LiTFSI) to an ionic liquid. In some embodiments, the mixture can be heated.

[0107] In certain embodiments in which a curing agent other than the low-valency ion is employed, the curing agent only partially contributes to the curing the thermoset polymer precursor. In some such embodiments, the amount of curing agent that is present is less than 80 mol%, less than 70 mol%, less than 60 mol%, or less than 50 mol% of the amount of curing agent that would be required to achieve full curing.

[0108] 13991335.1In certain embodiments in which a curing agent is used, the thermoset polymer (e.g., epoxy) precursor and the curing agent are present in a ratio between 2 / 3 and 1 / 3. In certain embodiments in which a curing agent is used, the thermoset polymer (e.g., epoxy) precursor and the curing agent are present in a ratio of 79:21.

[0109] In certain embodiments, the method of forming the composition comprises mixing the thermoset polymer precursor and the ionic liquid (which may also contain the low-valency cation and, optionally, the curing agent). The mixing may comprise, for example, stirring the mixture, using a magnetic mixer, using a mixing blade, or any other suitable mixing technique. In certain embodiments, the mixing is conducted under nitrogen. In certain embodiments, [H2O] and [O2] are less than 0.5 ppm during the mixing.

[0110] In certain embodiments, the method of forming the composition comprises degassing the combination of the thermoset polymer precursor and the ionic liquid (which may also contain the low-valency cation and, optionally, the curing agent). Some embodiments comprise stirring and degassing thermoset polymer (e.g., epoxy) precursor and / or thermoset polymer (e.g., epoxy) product (e.g., comprising thermoset polymer product cured by the curing agent) and a lithium solution (e.g., made by dissolving a lithium salt within ionic liquid).

[0111] In certain embodiments, the method of forming the composition comprises heating the combination of the thermoset polymer precursor and the ionic liquid (which may also contain the low-valency cation and, optionally, the curing agent). In some embodiments, the heating comprises heating the mixture at 120° C for 40 min and then heating the mixture at 150° C for 8 hours.

[0112] U.S. Provisional Patent Application No. 63 / 652,157, filed May 27, 2024, and entitled “Thermoset Structural Polymer Electrolyte,” is incorporated herein by reference in its entirety for all purposes.

[0113] The following example is intended to illustrate certain embodiments of the present invention, but does not exemplify the full scope of the invention.

[0114] EXAMPLE

[0115] This example describes the fabrication and testing of a composition comprising a combination of a thermoset epoxy and ionic liquid. In this work, EPON 862 (epoxy resin) with EPIKURE W (hardener) was used as the structural phase (50wt%) and a solution of bis(trifluoromethane)sulfonimide lithium salt (LiTFSI) in l-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI) was used as the ionic conductive phase (50wt%). By reducing the ratio of hardener-to-epoxy resin (relative to the recommended amount), the ionic conductivity and Young’s modulus (E) of the SPE system was able to be 13991335.1tailored. Even with no hardener (0% of W), the SPE could be partially cured via lithium salt-catalyzed epoxide ROP. When the hardener was added to the system at ratios lower than 100% of W, a dual curing process was induced, both by the lithium salt and the aromatic amine from the hardener. Moreover, no clear interface was visualized between structural and ionic conductive phases by scanning electron microscopy, indicating presence of highly interpenetrated bicontinuous phases at the nanoscale or even a single continuous phase.

[0116] Materials and Methods

[0117] Sample fabrication

[0118] Epoxy resin EPON 862 and EPIKURE curing agent W were purchased directly from Miller-Stephenson. The ionic liquid (IL) EMIM-TFSI and the Li salt LiTFSI were from Sigma Aldrich. Pure epoxy was made following the recommended ratio of 79:21 resin-to-hardener. The structural polymer electrolyte samples were fabricated using 50wt% of EMIM-TFSI with IM of LiTFSI and 50wt% of EPON&W. The quantity of the hardener was varied from the recommended amount to 2 / 3, to 1 / 3, and to no hardener (SPE-1W, SPE-2 / 3W, SPE1 / 3W and SPE-OW, respectively). See Table 1 for more details. All samples were made inside a nitrogen-filled glove box ([H2O], [O2] < 0.5 ppm), first stirring the IL with Li salt and W. Then, the EPON was added, stirred, and degassed until no bubbles were visible. The mixture was then poured into a stainless- steel coin cell case and heated from room temperature to 120°C for 40 min and then to 150 °C for 8 hours.

[0119] Table 1- DSC results for all samples.

[0120] IL with IM

[0121] EPON W HR Tg

[0122] Samples ID LiTFSI

[0123] (wt%) (wt%) (°C)

[0124] (wt%) (J / g)

[0125] SPE-1W 39.5 10.5 50 0 129.3

[0126] SPE-2 / 3W 42.5 7.5 50 18.9 97 SPE-1 / 3W 44.4 5.6 50 15.7 88.6 SPE-OW 50 0 50 105.9 - Epoxy 79 21 0 0 132.2

[0127] Epoxy uncured 79 21 0 300.9 - SPE-1 / 3W uncured 44.4 5.6 50 142.3 -

[0128]

[0129] SPE-OW uncured 50 0 50 340.9 -

[0130] Scanning electron microscopy (SEM)

[0131] Samples were imaged by a Zeiss Sigma 300 VP Field Emission SEM at 3 kV. Prior to imaging, the samples were broken in small pieces (to access its cross-section) by hand, and immersed and degassed into acetonitrile and isopropanol to remove the IL.

[0132] 13991335.1Thermal analysis

[0133] Differential scanning calorimetry was performed with a TA Instruments Discovery DSC RCS 1-3277 using the TA Instruments TRIOS Software version 4.4.1 for enthalpy and Tgcalculations. Approximately 9 mg of each sample was sealed in a hermetic aluminum DSC pan inside the glovebox. The samples were subjected to 2 heating cycles from 20°C to 300°C at a ramp rate of 5°C / min in nitrogen gas.

[0134] Electrochemical impedance spectroscopy (EIS)

[0135] After cure, the coin cell containing the SPE was glued to a stainless-steel spacer with silver paste to ensure good contact. This modified coin cell assembly (anode case - SPE -stainless steel spacer) was then placed inside a homemade split-cell using stainless steel as blocking electrodes. EIS measurements were performed using VMP3 (potentiostat with frequency response analyzer, Bio-logic) in ambient conditions with an open circuit potential of 10 mV amplitude and frequency range from 10-2to 106Hz. The obtained EIS data was analyzed using the circular fit feature from the EC-Lab software (Bio-Logic) in a Nyquist plot. Ionic conductivity was calculated using the x-axis cross over of the Nyquist plot as the real impedance of the SPE.

[0136] N anoindentation

[0137] The investigation of the mechanical properties was carried out using nanoindentation (Hystiron TI950 TriboIndenter). The indentation modulus values, referred to hereafter simply as modulus, were obtained per Oliver and Pharr’s method (Oliver, W.C. et al., “An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments,” J. Mater. Res. 7 (1992) 1564-1583, which is incorporated herein by reference) using a Berkovich tip and trapezoidal loading function (10 mN peak load for 5 seconds, 1 mN / s loading and unloading). A linear array of 30 quasi-static indents per sample was performed with a spacing of 20 times the measured indentation depth to avoid overlapping plastic zones.

[0138] Results and Discussion

[0139] SPE morphology

[0140] The morphology of the four SPE systems can be seen in FIGS 7A-7D. SPE-1W (FIG.

[0141] 7 A) shows a complete phase separation between the ionic liquid (circular pores) and the epoxy matrix. Despite these pores being uniform and well distributed over the entire sample, they were not interconnected, which was detrimental for ion mobility through the SPE. As the hardener amount was reduced (SPE-2 / 3W), a single phase started to appear (FIG. 7B), while some small circular pores were still visible. For both SPE-1 / 3W and 0W (FIGS. 7C and 7D, 13991335.1respectively) only one single phase could be visualized in SEM. The difference in texture between these two was related to the mechanical properties of the matrix, the SPE-OW went through significant plastic deformation before breaking during the sample preparation for SEM, while SPE-1 / 3W was observed to be more brittle.

[0142] Micro-CT images were taken with a voxel size of approximately 1 micrometer. No voids were perceived at that scale.

[0143] Thermal analysis

[0144] The DSC of both cured (FIG. 8A) and uncured (FIG. 8B) samples gives better insight into the characteristics of these SPEs. SPE-1W showed no exothermic peaks, indicating a fully-cured epoxy under the proposed cure conditions, which was also not affected by the IL or Li salt present in it. Indeed, no cured sample went through an exothermic event at temperatures under 150 °C (the maximum curing temperature). As the hardener amount was decreased, an exothermic peak appeared around 260°C, with a left shoulder around 230°C. The heat of reaction (HR) increased as the hardener decreased, indicating a lower degree of cure for a lower W. It is important to note that even with no hardener, SPE-OW was solid, with an estimated degree of cure of 69%, calculated (as discussed in Shanku, R., et al., “Rheological characteristics and cure kinetics of EPON 862 / W epoxy used in pultrusion,” Adv. Polym.

[0145] Technol. 16 (1997) 297-311, which is incorporated herein by reference) using the HR of the cured and uncured SPE-OW. See Table 1. This double peak can hence be associated with the curing of the epoxy promoted “by the Li salt,” as the same double peak was present in the cured and uncured samples without any hardener (SPE-OW), but not in the pure epoxy (containing only epon resin and W).

[0146] Moreover, FIG. 8B shows that the uncured SPE containing both W and IL (with Li salt) possessed the same double peak while another endothermic peak at about 92°C appeared, potentially related to the curing reaction by the hardener W, but at much lower temperature (about 181°C for uncured epoxy with only W). This effect can be associated with a catalytic effect of the lithium ions, or other synergistic effect. The total HR of the ROP is also drastically reduced for SPE-1 / 3W, further demonstrating this dual curing process, which also obviates calculating the degree of cure using the known approaches once the HR of each peak is intrinsically intertwined. Another characteristic of these blends is a small endothermic rise after about 280°C, which is likely associated with the beginning of a decomposition process.

[0147] The Tgalso increased with the amount of hardener, being almost equal for pure epoxy and SPE-1W, another indication that full cure was achieved. SPE-2 / 3W and SPE-1 / 3W showed a reduction in Tg, mainly associated with the lower degree of cure, but also due the higher

[0148] 13991335.1mobility of epoxy chains closely surrounded by the IL. SPE-OW displayed no apparent Tgabove room temperature, consistent with its rubbery physical state.

[0149] Ionic conductivity and mechanical properties

[0150] SPE-1W acted as a pure dielectric material. This is believed to be due to the lack of interconnection between IL-filled pores. It is believed that, as the dual curing process began, ionic channels started to be formed, resulting in some (but low) ionic conductivity for SPE-2 / 3W (FIG. 9A). With further reduction in the W hardener content, the ionic conductivity increased a few orders of magnitude (FIG. 9B), reaching levels normally associated with typical SPEs.

[0151] Table 2 provides a summary of nanoindentation modulus and ionic conductivity for the tested samples. Inversely, the nanoindentation modulus increased as W increased. SPE-OW yielded a modulus of 73 MPa, which is similar to polymer electrolytes blended with the same ratio of ionic liquid. SPE-1 / 3W achieved a modulus of 1.65GPa, twice the modulus of MVR444, one of the best epoxy / ionic liquid systems in literature, with also higher ionic conductivity. SPE-2 / 3W achieved a modulus of 2.43GPa. The pure epoxy (i.e., 79 wt% EPON and 21 wt% hardener W, with no LiTFSI) exhibited a modulus of 3.25 GPa.

[0152] Table 2- Nanoindentation and Ionic conductivity of SPEs.

[0153] Nanoindentation Ionic

[0154] Samples

[0155] modulus Conductivity

[0156] ID

[0157] (Gpa) (mS / cm)

[0158] SPE-1W 3.18 + 0.011 0

[0159] SPE-2 / 3W 2.43 + 0.014 0.0000514

[0160] SPE-1 / 3W 1.65 + 0.012 0.0073800

[0161]

[0162] SPE-OW 0.07 + 0.006 0.0312600

[0163] Additional samples were made using procedures similar to those used to fabricate the SPE-1 / 3W samples referenced above. The additional samples exhibited Young’s moduli of 867 MPa with ionic conductivities of 4x1 O'4S / cm.

[0164] Conclusions

[0165] This example shows how the dual curing process by a hardener and a lithium salt can drastically change the interaction between structural and ionic mediums, resulting in relatively high ionic conductivity while retaining mechanical properties. At the ratio of 33% of W, the SPE achieved an ionic conductivity of 7.4xl0'3mS / cm and a Eof 1.65GPa. Moreover, the lack of any observed porosity, notably when compared with “traditional” epoxy / IL systems, can further improve other mechanical properties such as durability metrics. The potential of such

[0166] 13991335.1systems is high, especially considering additional processing variations towards optimizing the thermoset SPE system for structural and energy storage properties simultaneously.

[0167] It should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific implementations described above. The specific implementations described above are disclosed as examples only.

[0168] While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present invention.

[0169] 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.”

[0170] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A

[0171] 13991335.1(optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0172] 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 separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0173] 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 elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0174] As used herein, “wt%” is an abbreviation of weight percentage. As used herein, “at%” is an abbreviation of atomic percentage. As used herein, “vol%” is an abbreviation of volumeric percentage.

[0175] Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way.

[0176] Accordingly, embodiments may be constructed in which acts are performed in an order different 13991335.1than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

[0177] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0178] When a portion (e.g., a layer, a structure, a region) is “on”, “adjacent”, “above”, “over”, “overlying”, or “supported by” another portion, it can be directly on the portion, or an intervening portion (e.g., layer, structure, region) may also be present. Similarly, when a portion is “below” or “underneath” another portion, it can be directly below the portion, or an intervening portion (e.g., layer, structure, region) may also be present. A portion that is “directly adjacent”, “directly on”, “immediately 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”, “above”, “adjacent”, “over”, “overlying”, “in contact with”, “below”, or “supported by” another portion, it may cover the entire portion or a part of the portion.

[0179] 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.

[0180] 13991335.1

Claims

CLAIMSWhat is claimed is:

1. A composition, comprising:thermoset polymer; andionic liquid in combination with the thermoset polymer;wherein:the Young’s modulus of the combination of the thermoset polymer and the ionic liquid is greater than or equal to 100 MPa; andthe composition has an ionic conductivity, with respect to at least one monovalent ion and / or at least one divalent ion, of at least IxlO'6S / cm.

2. A composition, comprising:thermoset polymer; andionic liquid;wherein:the thermoset polymer and the ionic liquid are present in bicontinuous phases or a single continuous phase; andless than or equal to 5 vol% of the composition is made up of voids having a maximum cross-sectional dimension of greater than or equal to 100 micrometers.

3. The composition of any one of claims 1-2, wherein less than or equal to 5 vol% of the composition is made up of voids having a maximum cross-sectional dimension of greater than or equal to 1 micrometer.

4. The composition of any one of claims 1-3, wherein the thermoset polymer comprises an epoxy.

5. The composition of any one of claims 1-4, wherein the composition has a volume of greater than or equal to 10,000 cubic micrometers.13991335.

16. The composition of any one of claims 1-5, wherein the composition is or is part of a membrane.

7. The composition of any one of claims 1-6, wherein the composition is or is part of a separator of an energy storage device.

8. The composition of any one of claims 1-7, wherein the ionic liquid comprises a low-valency cation.

9. The composition of any one of claims 1-8, wherein the ionic liquid comprises lithium.

10. The composition of any one of claims 1-9, wherein the composition has an ionic conductivity, with respect to lithium cations, of at least IxlO'6S / cm.

11. The composition of any one of claims 2-10, wherein the Young’s modulus of the combination of the thermoset polymer and the ionic liquid is greater than or equal to 100 MPa.

12. The composition of any one of claims 2-11, wherein the composition has an ionic conductivity, with respect to at least one monovalent ion and / or at least one divalent ion, of at least IxlO'6S / cm.

13. The composition of any one of claims 1-12, wherein the composition is a composite comprising the ionic liquid, the thermoset polymer, and at least one of nanofibers, nanotubes, and microfibers.

14. A method of forming a composition, comprising:establishing a combination of thermoset polymer precursor and ionic liquid, wherein the combination comprises a low-valency ion, such that the low-valency ion at least partially cures the thermoset polymer precursor to form thermoset polymer, wherein the curing results in bicontinuous phases or a single continuous phase comprising the thermoset polymer and the ionic liquid.13991335.

115. A method of forming a composition, comprising:establishing a combination of thermoset polymer precursor and ionic liquid, wherein the combination comprises a low-valency ion, such that the low-valency ion at least partially cures the thermoset polymer precursor to form thermoset polymer, wherein the curing results in a combination of thermoset polymer and ionic liquid, the combination having a Young’s modulus of greater than or equal to 100 MPa and an ionic conductivity, with respect to at least one monovalent ion and / or at least one divalent ion, of at least IxlO'6S / cm.

16. The method of any one of claims 14-15, wherein the thermoset polymer precursor comprises an epoxide.

17. The method of any one of claims 14-16, wherein the thermoset polymer precursor comprises diglycidyl ether bisphenol F.

18. The method of any one of claims 14-17, wherein the thermoset polymer precursor undergoes a chemical reaction with a component of the ionic liquid.

19. The method of claim 18, wherein the chemical reaction is a ring-opening polymerization reaction.

20. The method of any one of claims 14-19, further comprising including a hardener in the combination of the thermoset polymer precursor and the ionic liquid.

21. The method of claim 20, wherein the hardener contributes to the curing of the thermoset polymer precursor.

22. The method of any one of claims 14-21, wherein the low-valency ion comprises a lithium ion.

23. A composition comprising:a structural phase comprising a mixture of:13991335.1epoxy resin, andionic liquid.

24. The composition of claim 23, wherein the ionic liquid comprises bis(trifluoromethane)sulfonimide lithium salt [LiTFSI] and l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI) [IL].

25. The composition of any one of claims 23-24, wherein the epoxy resin comprises diglycidyl ether of bisphenol F.

26. The composition of claim 25, wherein the epoxy resin comprises EPON 862 [EPON],27. The composition of any one of claims 23-26, further comprising a curing agent for the epoxy resin, optionally wherein the curing agent comprises an aromatic amine.

28. The composition of claim 27, wherein the curing agent comprises EPIKURE W [W],29. The composition of any one of claims 23-28, wherein the composition consists of highly interpenetrated bicontinuous phases or a single continuous phase.

30. The composition of any one of claims 23-29, wherein the ratio of the epoxy resin to curing agent ranges between 2:3 and 1:3, or wherein the ratio of the epoxy resin to curing agent is 79:21.

31. The composition of claim 30, wherein the ratio of EPON:W ranges between 2:3 and 1:3, or wherein the ratio of EPON:W is 79:21.

32. The composition of any one of claims 23-31, with an ionic conductivity between 0.005xl0'3mS / cm and 7xl0'3mS / cm.13991335.

133. The composition of any one of claims 23-32, with a modulus of at least 1.65 GPa.

34. The composition of any one of claims 23-33, with a Tgbetween 88° C and 97° C.

35. A method of making the composition of any one of claims 23-34, the method comprising:mixing the epoxy resin with curing agent to produce an epoxy product; adding the epoxy product to a lithium solution; andheating the mixture.

36. The method of claim 35, further comprising stirring IL with lithium salt to produce the lithium solution.

37. The method of claim 36, wherein the lithium salt comprises LiTFSI.

38. The method of any one of claims 35-37, further comprising stirring and degassing the added epoxy product and lithium solution.

39. The method of any one of claims 35-38, wherein the mixing comprises mixing the epoxy resin with the curing agent in a ratio between 2 / 3 and 1 / 3.

40. The method of any one of claims 35-39, wherein the mixing comprises mixing the epoxy resin with the curing agent in a ratio of 79:21.

41. The method of any one of claims 35-40, wherein the heating comprises heating the mixture at 120° C for 40 min and at 150° C for 8 hours.

42. The method of any one of claims 35-41, wherein the epoxy product and lithium solution are mixed under nitrogen.

43. The method of claim 42, wherein [H2O] and [O2] are less than 0.5 ppm.13991335.1

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