Method for assembling a bipolar membrane, bipolar membrane, and use of said bipolar membrane

Abstract

A method for assembling a bipolar membrane is provided that eliminates or at least reduces one or more of the problems of the prior art and / or is more efficient as compared to prior art methods and systems. The present invention relates to a method of assembling a bipolar membrane and the bipolar membrane, the method comprising the steps of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer, electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning an attachment layer, and electrospinning and / or centrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer.

Description

[Technical field]

[0001] The present invention relates to a method for assembling a bipolar membrane, to a bipolar membrane and to uses of said bipolar membrane. Furthermore, the present invention relates to a bipolar membrane obtainable by the method for assembling a bipolar membrane according to the present invention. [Background technology]

[0002] Bipolar membranes can have multiple layers, for example, a cation exchange layer, a mixed anion and cation exchange layer, and an anion exchange layer. In conventional bipolar membranes, the cation exchange layer and the anion exchange layer are bonded together, for example, by hot pressing, or by casting, or by extrusion. Heterogeneous bipolar membranes are formed by combining an anion exchange layer composed of anion exchange resin particles in a supported inert polymer with a cation exchange layer composed of cation exchange resin particles in a supported inert polymer. The support polymer may be formed, for example, from polyethylene or polypropylene or polyetheretherketone. Homogeneous bipolar membranes are formed by combining an anion exchange layer made of a polymer with positively charged residues, for example, tertiary and quaternary ammonium groups, with a cation exchange layer made of a polymer with negatively charged residues, for example, carboxylate and sulfonate groups. Conventional fabrication of bipolar membranes is carried out by connecting the above-mentioned anion-exchange layer and cation-exchange layer by casting and / or by attaching the anion-exchange layer and the cation-exchange layer at a water-splitting 2D interface between the anion-exchange layer and the cation-exchange layer, where a water-splitting catalyst can be applied, for example, by casting or spraying.

[0003] A problem with conventional 2D interfacial bipolar membranes and / or methods for producing such bipolar membranes is delamination, also referred to as swelling, which can occur due to pressure (osmotic pressure) building up at the interfacial junction between the anion and cation exchange layers, for example, during start-up and shut-down of the electrodialysis system. This problem becomes even more problematic when the bipolar membranes are enlarged in size and when said membranes are produced in a batch-wise process. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a method for assembling a bipolar membrane that eliminates or at least reduces one or more of the above problems and / or is more efficient compared to conventional methods and systems. [Means for solving the problem]

[0005] This object is achieved by a method for assembling a bipolar membrane, the method comprising the steps of: - electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer; - electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the bonding layer, and - electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 shows a schematic overview of the method according to the invention. [Diagram 2] FIG. 2 shows a schematic overview of a bipolar membrane according to the present invention comprising a bonding layer, a first cation exchange layer, and a first anion exchange layer. [Diagram 3]FIG. 3 shows a schematic overview of an alternative bipolar membrane according to the present invention, comprising a tie layer, first and second cation exchange layers, and first and second anion exchange layers. [Figure 4] FIG. 4 shows a schematic overview of a further alternative bipolar membrane according to the present invention comprising a first water splitting catalyst and a second water splitting catalyst electrosprayed in a stepwise manner. [Diagram 5] FIG. 5 shows the current density versus bipolar membrane voltage for a bipolar membrane according to the present invention and a conventional bipolar membrane. [Figure 6] FIG. 6 shows the water binding curves for a bipolar membrane according to the invention tested in solutions of 0.5M and 1M HCl and NaOH. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The method according to the present invention may start with electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of a first cation exchange layer, may start with electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of a bonding layer, or may start with electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of a first anion exchange layer. Depending on the layer that is assembled first, adjacent layers may be assembled subsequent to the first assembled layer. For example, the method according to the present invention may start with electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of a bonding layer. This step may be followed by a step of electrospinning and / or centrifugal spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer. In this way, the first cation exchange layer is disposed on one side of the bonding layer. This step may then be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. This first anion exchange layer is attached adjacent to the bare surface of the attachment layer. Alternatively, following the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the attachment layer, the first anion exchange layer may be electrospun and / or centrifugally spinning and / or electrocentrifugally spinning first, and then the first cation exchange layer may be electrospun and / or centrifugally spinning and / or electrocentrifugally spinning.

[0008] Alternatively, the method of the present invention may begin with electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer. Preferably, the first cation exchange layer is assembled adjacent to or on a carrier, which may be inert with respect to the first cation exchange layer. Preferably, the carrier is an electrically conductive carrier layer.

[0009] Thus, in a preferred embodiment, the method according to the invention comprises the step of providing a carrier. The carrier, which is preferably inert to any of the layers (cation exchange layer, anion exchange layer and attachment layer), allows the bipolar membrane to be easily removed and damage to the bipolar membrane is reduced. Preferably, the carrier is an electrically conductive carrier layer.

[0010] The step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer may be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning an attachment layer, which is assembled adjacent to (on the bare surface of) the first cation exchange layer. Furthermore, the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the attachment layer may be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. The first anion exchange layer is attached adjacent to the attachment layer.

[0011] In another alternative embodiment, the method of the present invention may begin with electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. Preferably, the first anion exchange layer is assembled adjacent to or on a carrier, which may be inert to the first anion exchange layer. Preferably, the carrier is an electrically conductive carrier layer.

[0012] The step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first anion exchange layer may be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning an attachment layer, which is assembled adjacent to (on the bare surface of) the first anion exchange layer. Furthermore, the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the attachment layer may be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer. The first cation exchange layer is disposed adjacent to the attachment layer.

[0013] In other words, the different layers (cation exchange layer, attachment layer, anion exchange layer) may be applied in any desired order, with the attachment layer having an adjacent cation exchange layer and an adjacent anion exchange layer on the other side of the attachment layer, such that the cation exchange layer and the anion exchange layer are each provided on opposite sides of the attachment layer.

[0014] It should be noted that assembling the different layers includes operatively linking the layers (cation exchange layer, junction layer, anion exchange layer) which indicates an interaction between the layers and refers to the fact that cations, e.g., protons, and / or anions, e.g., hydroxide ions, and / or electrons, can be transported from one side of the bipolar membrane to the other side of the membrane.

[0015] It has been found that the first cation exchange layer, the bonding layer, and the first anion exchange layer can be assembled by multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning. Multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows different compounds to be included in a single layer. Furthermore, multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows compounds with different solubilities and / or compounds soluble in immiscible solvents to be included in a single layer. It should be noted that multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning is not limited to the first cation exchange layer, the bonding layer, and the first anion exchange layer.

[0016] In a preferred embodiment, the electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning step comprises two spinneret, three spinneret, or four spinneret electrospinning and / or centrifugal spinning, preferably two spinneret electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning.

[0017] Multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning includes electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning with multiple spinnerets. For example, dual electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning includes electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning with two spinnerets, and triple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning includes electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning with three spinnerets. Thus, dual electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows for the assembly of a single layer that includes a compound that is dissolved or dispersed in an aqueous solvent or dispersion medium and a compound that is dissolved or dispersed in a non-aqueous solvent or dispersion medium and / or an organic solvent or dispersion medium. It should be noted that one spinneret provides compounds that are soluble or dispersible in an aqueous solvent or dispersion medium, while the other spinneret provides compounds that are soluble or dispersible in a non-aqueous solvent or dispersion medium and / or an organic solvent or dispersion medium.

[0018] A further advantage of multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning is that it uses a versatile way to incorporate nanomaterials into polymeric nanofiber structures in a controlled and / or uniform manner by allowing the simultaneous use of aqueous solutions and / or dispersions and organic solvent-based polymer dispersions and / or solutions by multiple, e.g. dual, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning.

[0019] Furthermore, the method according to the present invention provides a versatile way to introduce compounds, e.g. nanomaterials, into polymeric nanofiber structures in a controlled and / or uniform manner by allowing the simultaneous use of aqueous solutions / dispersions and / or organic solvents containing polymer solutions.

[0020] For example, fabricating the first cation exchange layer by double electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows the first water splitting catalyst and the first cation exchange polymer to be provided separately in the first cation exchange layer, resulting in the incorporation of an aqueous soluble / dispersible first water splitting catalyst and a non-aqueous soluble / dispersible first cation exchange polymer into the first cation exchange layer.

[0021] It should be noted that this approach is also applicable to additional cation-exchange layers, anion-exchange layers, and bonding layers.

[0022] Electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning different layers allows to achieve a bipolar membrane with uniformly connected layers and compact layers. In other words, layers are directly attached to adjacent layers and / or the adhesion of two adjacent layers is uniformly distributed. The advantage is that the delamination of the assembled bipolar membrane is reduced compared to conventional methods of assembling bipolar membranes. As a result, the method according to the present invention provides a bipolar membrane that is relatively less prone to delamination. Thus, a more efficient and effective method for assembling bipolar membranes is obtained.

[0023] Another advantage of the method according to the invention is that the homogeneously connected layers of the bipolar membrane provide a bipolar membrane that is highly chemically resistant and / or mechanically stable. In fact, the bipolar membrane is more chemically resistant and / or mechanically stable than conventional bipolar membranes. Thus, the method according to the invention allows for efficient and effective assembly of bipolar membranes.

[0024] In fact, the method according to the invention allows bipolar membranes without any surface connections between the different layers due to the ever-present provision of compounds to assemble the different layers.

[0025] Assembling a (multi-layer) bipolar membrane by using multiple, e.g. double, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows the simultaneous use of aqueous solutions and / or dispersions with inorganic and / or organic catalysts in the organic phase and allows single, multiple, e.g. double, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of one or more (preferably two) different polymer solutions and / or dispersions in the organic phase.

[0026] Furthermore, assembling (multi-layer) bipolar membranes by using multiple, e.g. double, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows the simultaneous use of aqueous solutions and / or dispersions with inorganic and / or organic catalysts in the organic phase and allows single, multiple, e.g. double, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of one or more (preferably two) different polymer solutions and / or dispersions in the organic phase, H + and OH - The use of nanometer-sized silica, preferably 2-4 nanometer-sized silica, as an inorganic catalyst for the water splitting of H + and OH - This involves the use of poly(4-vinylphenol) as an organic catalyst for the water splitting of

[0027] In a preferred embodiment, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning of the cation exchange layer, the attachment layer, and / or the anion exchange layer is electrospinning of the cation exchange layer, the attachment layer, and / or the anion exchange layer.

[0028] It has been found that electrospinning of the cation exchange layer, the attachment layer, and / or the anion exchange layer provides the layers in an effective and efficient manner.

[0029] In a preferred embodiment of the present invention, the method of the present invention further comprises the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer and / or the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second anion exchange layer comprising a second anion exchange polymer.

[0030] Optionally, the first cation exchange polymer and the second cation exchange polymer are the same and / or the first anion exchange polymer and the second anion exchange polymer are the same.

[0031] The steps of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer and / or electrospinning and / or centrifugally spinning a second anion exchange layer comprising a second anion exchange polymer may be performed in addition to the steps of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer and / or electrospinning and / or centrifugally spinning a first anion exchange layer.

[0032] Therefore, alternatively, the method according to the invention may start with a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer. Preferably, the second cation exchange layer is assembled adjacent to or on a carrier, which may be inert to the second cation exchange layer. This step may be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer, which is assembled adjacent to the second cation exchange layer. The bipolar membrane is further assembled as described above.

[0033] In another alternative embodiment, the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the second cation exchange layer is performed after the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer. It should be noted that the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the second cation exchange layer may be performed as a final step in assembling multiple layers or as an intermediate step in assembling multiple layers.

[0034] In another alternative embodiment, the method of the present invention may begin with a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second anion exchange layer comprising a second anion exchange polymer. Preferably, the second anion exchange layer is assembled adjacent to or on a carrier, which may be inert to the second anion exchange layer. This step may be followed by a step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer, which is assembled adjacent to the second anion exchange layer. The bipolar membrane is further assembled as described above.

[0035] The advantage of the method including electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer and / or electrospinning and / or centrifugally spinning a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer is that the first cation exchange layer and / or the first anion exchange layer are protected against harsh conditions. As a result, the valuable first water splitting catalyst and / or the second water splitting catalyst are protected. Thus, the efficiency of the bipolar membrane is maintained and does not deteriorate due to loss of water splitting catalyst over the life of the bipolar membrane.

[0036] In a preferred embodiment of the present invention, the steps of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer and / or electrospinning and / or centrifugally spinning the first anion exchange layer comprise electrospraying the first water splitting catalyst and / or the second water splitting catalyst in a stepwise (progressive) manner, preferably with a concentration of the first water splitting catalyst and / or the second water splitting catalyst decreasing in a direction extending from adjacent bonding layers.

[0037] It should be noted that "in a stepwise manner" indicates that the concentration of the first water splitting catalyst and / or the second water splitting catalyst increases or decreases through the thickness of the layer. It should be understood that the concentration of the cation exchange polymer and / or the anion exchange polymer exhibits an inverse relationship. In other words, the concentration of the first water splitting catalyst and / or the second water splitting catalyst changes or varies through the thickness of the first cation exchange layer and / or the first anion exchange layer.

[0038] Additionally, it should be noted that the thickness of the desired layer or layers is defined in a direction substantially perpendicular to adjacent surfaces of the bonding layer.

[0039] The use of dual electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows the inclusion of two compounds with different properties in a single layer. In this respect, the method according to the present invention allows the inclusion of an aqueous solution or dispersion of a first water splitting catalyst and / or a second water splitting catalyst, and a non-aqueous solution or dispersion of a cation exchange polymer and / or an anion exchange polymer. As a result, a combination of compounds can be introduced into a single layer.

[0040] Another advantage of electrospraying the first water splitting catalyst and / or the second water splitting catalyst in a stepwise manner is that a high concentration of the first water splitting catalyst and / or the second water splitting catalyst can be applied near the bonding layer, and / or the bonding layer and the first cation exchange layer and / or the first anion exchange layer can be gently fused to each other. As a result, the connection between these layers is broken, and a relatively strong membrane is obtained. It should be noted that the connection can refer to the integration of two adjacent layers and / or the adhesion of two adjacent layers.

[0041] Another advantage is that all layers are gently fused to each other. For example, the concentration of the first water splitting catalyst and / or the second water splitting catalyst can be zero on the surface of the cation exchange layer and / or the anion exchange layer opposite to the surface adjacent to the bonding layer. This allows the amount of layers to be reduced and reduces the number of connections between layers.

[0042] In a preferred embodiment, the method according to the invention comprises a method of continuous electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning, where different compounds are introduced simultaneously into the layers. By varying the concentration and / or composition of the inputs, different structures and compositions within the bipolar membrane can be achieved. This can be achieved by using multiple spinnerets, for example by using two or three spinnerets. As a result, a bipolar membrane is obtained in which the layers are defined by the composition over a defined thickness of the bipolar membrane. For conventional bipolar membranes, the layers are defined by the edges between different preformed layers.

[0043] In a preferred embodiment of the present invention, the first water splitting catalyst and the second water splitting catalyst are independently one or more selected from the group consisting of porous silica materials, aluminum silicates, zeolites, and organic catalysts. Preferably, the organic catalyst is one or more selected from the group consisting of poly(4-vinylphenol) and polyethylene glycol.

[0044] In a preferred embodiment of the present invention, the first water splitting catalyst and the second water splitting catalyst may be one or more independently selected from the group consisting of MCM-41, TiO2, IrO2, Al(OH)3, graphene oxide, graphite oxide, ZIF-7, ZIF-8, ZIF-90, MOF-5, IRMOF-1, HKUST-1, CuTPA, SiO2, and Mn(HCOO)2. Preferably, the first water splitting catalyst and / or the second water splitting catalyst may be MCM-41.

[0045] It should be noted that MCM-41 is a trademark, which is a developed mesoporous silica catalyst.

[0046] Further points to note: - ZIF-7 (zeolitic imidazolate framework 7) is Zn(bim)2, where bim stands for benzimidazole, and is formed by connecting a Zn(II) ion with a benzimidazole anion; - ZIF-8 (zeolitic imidazolate framework 8) is formed by Zn(II) ions coordinated by four imidazolate rings; - ZIF-90 (Zeolic Imidazolate Framework 90) is formed by Zn(II) nitrate and imidazolate-2-carboxaldehyde; - MOF-5 is a cubic metal-organic framework with the formula Zn4O(BDC)3, where BDC is 1,4-benzodicarboxylate; - IRMOF-1 is a cubic metal-organic framework with the formula Zn4O(BDC)3, where BDC is 1,4-benzodicarboxylate; - HKUST-1 is a framework of square metal units connected by benzene-1,3,5-tricarboxylates, for example copper benzene-1,3,5-tricarboxylate; - Cu-TPA is copper terephthalate.

[0047] It has been found that the first water splitting catalyst and the second water splitting catalyst, which are one or more independently selected from the group consisting of MCM-41, TiO2, IrO2, Al(OH)3, graphene oxide, graphite oxide, ZIF-7, ZIF-8, ZIF-90, MOF-5, IRMOF-1, HKUST-1, CuTPA, SiO2, and Mn(HCOO)2, provide an efficient and effective bipolar membrane. It has also been found that the first water splitting catalyst and / or the second water splitting catalyst, which are MCM-41, provide an efficient and effective bipolar membrane. Preferably, the first water splitting catalyst and the second water splitting catalyst are the same.

[0048] The advantage of the first water splitting catalyst and the second water splitting catalyst being the same is that only one solution / dispersion is provided to one of the spinnerets of the electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning apparatus.

[0049] In a preferred embodiment according to the invention, the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer.

[0050] Providing a tie layer comprising a third cation exchange polymer and / or a third anion exchange polymer allows for an efficient and effective bipolar membrane. Preferably, the third cation exchange polymer is provided by a spinneret and the third anion exchange polymer is provided by another spinneret.

[0051] In a preferred embodiment, the first cation exchange polymer and / or the second cation exchange polymer and / or the third cation exchange polymer are the same. In a further preferred embodiment, the first anion exchange polymer and / or the second anion exchange polymer and / or the third anion exchange polymer are the same.

[0052] In a preferred embodiment of the present invention, each cation exchange polymer may be one or more independently selected from the group consisting of sulfonated polyetheretherketone, copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone.

[0053] Experiments have demonstrated that cation exchange polymers independently selected from the group of sulfonated polyetheretherketone, copolymers of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), sulfonated polyethersulfone provide efficient and effective bipolar membranes.

[0054] It should be noted that each cation exchange polymer, for example, the first cation exchange polymer, the second cation exchange polymer, and the third cation exchange polymer, are independently selected from the above group. Thus, the first cation exchange polymer may be one or more selected from the group of sulfonated polyetheretherketone, copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone. The second cation exchange polymer and / or the third cation exchange polymer may optionally be one or more independently selected from the group of sulfonated polyetheretherketone, copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone.

[0055] In a preferred embodiment of the present invention, each anion exchange polymer may be one or more independently selected from the group consisting of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3.

[0056] It should be noted that FAA-3 is a trademark and refers to poly[oxy(2,6-dimethyl-1,4-phenylene)]-based polymers and / or aromatic polymers polyphenylene oxide having quaternary ammonium groups.

[0057] Experiments have shown that anion exchange polymers selected from the group consisting of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3 provide efficient and effective bipolar membranes.

[0058] It should be noted that each anion exchange polymer, for example, the first anion exchange polymer, the second anion exchange polymer, and the third anion exchange polymer, are independently selected from the above group. Thus, the first anion exchange polymer may be one or more selected from the group of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3. The second anion exchange polymer and / or the third anion exchange polymer may optionally be one or more independently selected from the group of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3.

[0059] In a preferred embodiment, the first cation exchange polymer and the second and / or third cation exchange polymer may be the same, and further, the first anion exchange polymer and the second and / or third anion exchange polymer may be the same.

[0060] In a preferred embodiment according to the invention, each cation exchange polymer may be a sulfonated polyetheretherketone and / or each anion exchange polymer may be FAA-3.

[0061] It has been found that sulfonated polyetheretherketone as the cation exchange polymer and / or FAA-3 as the anion exchange polymer provide efficient and effective bipolar membranes. Indeed, efficient and effective water dissociation has been achieved with bipolar membranes in which the respective cation exchange polymer may be sulfonated polyetheretherketone and / or the respective anion exchange polymer may be FAA-3.

[0062] In a preferred embodiment of the present invention, each of the one or more cation exchange polymers and / or each of the one or more anion exchange polymers may be dissolved and / or dispersed in a solvent and / or dispersion medium, and for each exchange polymer, the solvent may be one or more independently selected from the group: dimethylacetamide, dimethylformamide, propanol, dimethylsulfoxide, N-methyl-2-pyrrolidone.

[0063] It should be noted that the solvent and / or dispersion medium is independently selected from the group of dimethylacetamide, dimethylformamide, propanol, dimethylsulfoxide, N-methyl-2-pyrrolidone for each individual exchange polymer. In other words, the solvent and / or dispersion medium is independently selected from the group of dimethylacetamide, dimethylformamide, propanol, dimethylsulfoxide, N-methyl-2-pyrrolidone for the first cation exchange polymer and / or the second cation exchange polymer and / or the third cation exchange polymer and / or the first anion exchange polymer and / or the second anion exchange polymer and / or the third anion exchange polymer. Preferably, the solvent / dispersion medium is dimethylacetamide.

[0064] The advantage of independent selection of solvents and / or carriers for different cation and anion exchange polymers is that said polymers can be independently provided to the desired layer. The use of multiple electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning allows the introduction of different (exchange) polymers simultaneously to the desired layer.

[0065] In a preferred embodiment, the (exchange) polymer may be dissolved or dispersed in a solvent or dispersion medium, and the solution or dispersion contains 15% to 30% by weight of the (exchange) polymer. Preferably, the cation exchange polymer may be dissolved or dispersed in the solvent or dispersion medium in the range of 15% to 25% by weight, preferably in the range of 18% to 22% by weight, and / or the anion exchange polymer may be dissolved or dispersed in the solvent or dispersion medium in the range of 20% to 30% by weight, preferably in the range of 24% to 28% by weight.

[0066] In a preferred embodiment of the present invention, the first water splitting catalyst and the second water splitting catalyst may be dissolved and / or dispersed in a solvent and / or dispersion medium, and for each water splitting catalyst, the solvent and / or dispersion medium may be one or more independently selected from the group consisting of water, methanol, ethanol, and propanol.

[0067] Dissolving and / or dispersing the first water splitting catalyst and / or the second water splitting catalyst in one or more independently selected from the group consisting of water, methanol, ethanol, and propanol enables the steps of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer and electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first anion exchange polymer, respectively, to be carried out efficiently and effectively.

[0068] It has been found that a solution and / or dispersion comprising 90% water and 10% ethanol provides an efficient and effective solution or dispersion comprising the first water splitting catalyst and / or the second water splitting catalyst.

[0069] Furthermore, the first water splitting catalyst and / or the second water splitting catalyst may be present in a solution or dispersion containing the first water splitting catalyst or the second water splitting catalyst in an amount of 0.1 to 5% by weight, preferably in an amount of 0.5 to 3% by weight, more preferably in an amount of 1 to 2.5% by weight, and most preferably in an amount of about 2% by weight.

[0070] Providing a solution / dispersion containing the first water splitting catalyst or the second water splitting catalyst in an amount of 0.1 wt % to 5 wt %, preferably 0.5 wt % to 3 wt %, more preferably 1 wt % to 2.5 wt %, and most preferably about 2 wt %, in the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer and / or the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first anion exchange polymer, respectively, enables an efficient and effective method according to the present invention.

[0071] In a preferred embodiment, the first water splitting catalyst and / or the second water splitting catalyst are dissolved and / or dispersed in 90% water and 10% ethanol, preferably the first water splitting catalyst and the second water splitting catalyst are MCM-41, and the cation exchange polymer and / or the anion exchange polymer are dissolved and / or dispersed in dimethylacetamide. Preferably, the solution and / or dispersion of the first water splitting catalyst and / or the second water splitting catalyst contains about 2% by weight of the first water splitting catalyst and / or the second water splitting catalyst, and the solution and / or dispersion of the cation exchange polymer and / or the anion exchange polymer contains 18% to 22% by weight of the cation exchange layer polymer, or 24% to 28% by weight of the anion exchange polymer. The above solution / dispersion is used in the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the bonding layer, the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer, and / or the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first anion exchange layer.

[0072] In a preferred embodiment of the present invention, the method of the present invention further comprises a pressing step, and preferably the pressing step comprises a hot pressing step. Preferably, the hot pressing step may be carried out at a temperature in the range of 120°C to 180°C, preferably at a temperature in the range of 130°C to 170°C, more preferably at a temperature in the range of 140°C to 160°C, and most preferably at a temperature of about 150°C.

[0073] Pressing the different layers together allows for the compression and densification of the different layers and / or membranes. As a result, efficient and effective membranes can be obtained. In fact, bipolar membranes with lower transmembrane voltages compared to conventional bipolar membranes have been obtained.

[0074] In a preferred embodiment according to the invention, the pressing step may be carried out at a pressure in the range of 150 bar to 250 bar, preferably at a pressure of 175 bar to 225 bar, more preferably at a pressure of 195 bar to 205 bar, most preferably at a pressure of about 200 bar. Preferably, the hot pressing step may be carried out for a period of up to 2 hours, preferably in the range of 0.1 hour to 2 hours, more preferably in the range of 0.1 hour to 1.5 hours, even more preferably in the range of 0.1 hour to 1 hour, most preferably in the range of 0.1 hour to 0.25 hours.

[0075] Carrying out the hot pressing step at a pressure in the range of 150 bar to 250 bar, preferably at a pressure of 175 bar to 225 bar, more preferably at a pressure of 195 bar to 205 bar, and most preferably at a pressure of about 200 bar, for a period of up to 2 hours, preferably in the range of 0.1 hours to 2 hours, more preferably in the range of 0.1 hours to 1.5 hours, even more preferably in the range of 0.1 hours to 1 hour, and most preferably in the range of 0.1 hours to 0.25 hours provides an efficient and effective membrane with efficient and effective water dissociation.

[0076] In a preferred embodiment, the pressing step provides a bipolar membrane having a thickness in the range of 30 μm to 120 μm, preferably 30 μm to 100 μm, and more preferably 30 μm to 80 μm.

[0077] In a preferred embodiment of the present invention, the method of the present invention further comprises a step of conditioning the bipolar membrane. Preferably, the conditioning step is carried out in an aqueous sodium chloride solution having a concentration in the range of 0.5 M to 1.5 M, preferably in the range of 0.75 M to 1.25 M, more preferably about 1 M.

[0078] Conditioning the membrane in an aqueous sodium chloride solution having a concentration in the range of 0.5M to 1.5M, preferably in the range of 0.75M to 1.25M, more preferably about 1M, provides a cost-effective bipolar membrane.

[0079] The present invention also relates to a bipolar membrane comprising: - bonding layer, a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer, the first cation exchange layer may be assembled adjacent to the attachment layer; and a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer, the first anion exchange layer may be assembled adjacent to the bonding layer; Here, the first cation exchange layer has a concentration of a first water splitting catalyst that varies in a direction extending from the adjacent bonding layer, and / or the first anion exchange layer has a concentration of a second water splitting catalyst that varies in a direction extending from the adjacent bonding layer.

[0080] In other words, in the bipolar membrane, the first cation exchange layer has a concentration of a first water splitting catalyst that varies in a direction extending from the adjacent bonding layer, and / or the first anion exchange layer has a concentration of a second water splitting catalyst that varies in a direction extending from the adjacent bonding layer.

[0081] The bipolar membrane provides the same or similar effects and advantages as those described with respect to the method of the present invention.

[0082] It should be noted that assembling the different layers includes operably linking these layers (cation exchange layer, junction layer, anion exchange layer) indicating an interaction between these layers such that protons and / or anions and / or electrons can be transported from one side of the bipolar membrane to the other side of the membrane.

[0083] An advantage of the bipolar membrane according to the present invention is that it has nanomaterials incorporated into the polymeric nanofiber structure in a controlled and uniform manner by allowing the simultaneous use of aqueous solutions and / or dispersions and polymer solutions and / or dispersions based on organic solvents and / or carrier media using dual electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning.

[0084] In a preferred embodiment of the present invention, the bipolar membrane further comprises a second cation exchange layer comprising a second cation exchange polymer, which may be assembled adjacent to the first cation exchange layer, and / or the bipolar membrane comprises a second anion exchange layer comprising a second anion exchange polymer, which may be assembled adjacent to the first anion exchange layer.

[0085] The advantage of a bipolar membrane comprising a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer and / or a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer is that the first cation exchange layer and / or the first anion exchange layer are protected against harsh conditions. As a result, the valuable first water splitting catalyst and / or the second water splitting catalyst are protected. Thus, the efficiency of the bipolar membrane is maintained and does not deteriorate due to loss of the first water splitting catalyst and / or loss of the second water splitting catalyst over the life of the bipolar membrane.

[0086] Furthermore, as a result of the protective layer, a membrane with high cost efficiency is achieved. In a preferred embodiment of the present invention, the first water splitting catalyst and the second water splitting catalyst may be one or more independently selected from the group consisting of MCM-41, TiO2, IrO2, Al(OH)3, graphene oxide, graphite oxide, ZIF-7, ZIF-8, ZIF-90, MOF-5, IRMOF-1, HKUST-1, CuTPA, SiO2, and Mn(HCOO)2. Preferably, the first water splitting catalyst and the second water splitting catalyst may be the same. In a preferred embodiment, the first water splitting catalyst and / or the second water splitting catalyst may be MCM-41.

[0087] The advantage of the first water splitting catalyst and the second water splitting catalyst being the same is that only one solution / dispersion is provided to one of the spinnerets of the electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning apparatus.

[0088] In a preferred embodiment according to the invention, the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer.

[0089] Providing a tie layer comprising a third cation exchange polymer and / or a third anion exchange polymer allows for an efficient and effective bipolar membrane. Preferably, the third cation exchange polymer is provided by one spinneret and the third anion exchange polymer is provided by another spinneret.

[0090] In a preferred embodiment, the first cation exchange polymer and / or the second cation exchange polymer and / or the third cation exchange polymer are the same. In a further preferred embodiment, the first anion exchange polymer and / or the second anion exchange polymer and / or the third anion exchange polymer are the same.

[0091] In a preferred embodiment of the present invention, each cation exchange polymer may be one or more independently selected from the group consisting of sulfonated polyetheretherketone, copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone.

[0092] It should be noted that each cation exchange polymer, for example, the first cation exchange polymer, the second cation exchange polymer, and the third cation exchange polymer, are independently selected from the above group. Thus, the first cation exchange polymer may be one or more selected from the group of sulfonated polyetheretherketone, poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether copolymer, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone. The second cation exchange polymer and / or the third cation exchange polymer may optionally be one or more independently selected from the group of sulfonated polyetheretherketone, poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether copolymer, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone.

[0093] In a preferred embodiment of the present invention, each anion exchange polymer may be one or more independently selected from the group consisting of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3.

[0094] It should be noted that each anion exchange polymer, the first anion exchange polymer, for example, the second anion exchange polymer, and the third anion exchange polymer, are independently selected from the above group. Thus, the first anion exchange polymer may be one or more selected from the group of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3. The second anion exchange polymer and / or the third anion exchange polymer may optionally be one or more independently selected from the group of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3.

[0095] In a preferred embodiment of the present invention, the bipolar membrane does not have a spacer.

[0096] It should be noted that a bipolar membrane without spacers allows for the assembly of a bipolar membrane that includes multiple layers that are not separated from one another, which allows the bipolar membrane to be assembled in a continuous manner, in other words, the bipolar membrane is not blocked by separate layers.

[0097] The invention also relates to a bipolar membrane according to the invention which is obtainable by the method according to the invention and / or a bipolar membrane which is obtainable by the method according to the invention.

[0098] The bipolar membrane according to the invention which can be obtained by the method according to the invention and / or the bipolar membrane which can be obtained by the method according to the invention has the same effects and advantages as described for the method according to the invention.

[0099] In a preferred embodiment, the bipolar membrane has a thickness in the range of 30 μm to 120 μm, preferably in the range of 30 μm to 100 μm, more preferably in the range of 30 μm to 80 μm.

[0100] The invention also relates to the use of the bipolar membrane according to the invention in hydrogen production, acid-based flow batteries, fuel cells, carbon dioxide capture and / or inorganic and / or organic acid-based production and / or recovery. The use of the bipolar membrane according to the invention provides the same effects and advantages as described for the method according to the invention and the bipolar membrane according to the invention.

[0101] Use of the bipolar membranes of the present invention provides efficient and effective hydrogen production, acid-based flow batteries, fuel cells, carbon dioxide capture, and / or inorganic and / or organic acid-based production and / or capture.

[0102] In a preferred embodiment of the present invention, the bipolar membrane has an overvoltage of at least 1000 Am -2 has a current density of

[0103] In a preferred embodiment, the ion exchange resin has an overvoltage of less than 100 mV and is at least 1000 Am -2 The current density of H + and OH - This compares with the reversible potential of 828 mV for the decomposition of water into

[0104] The present invention also relates to a system comprising a bipolar membrane according to the present invention.

[0105] The system according to the invention provides the same effects and advantages as those described with respect to the method according to the invention, the bipolar membrane according to the invention and the use of the bipolar membrane according to the invention.

[0106] Further advantages, features and details of the present invention will now be described on the basis of preferred embodiments thereof with reference to the accompanying drawings, in which: A method 10 (FIG. 1) for assembling a bipolar membrane is carried out along a sequence of different steps.

[0107] In the illustrated embodiment, method 10A begins with step 16 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer. Optionally, method 10 begins with step 12 of providing a carrier, followed by step 16. Step 16 may be followed by step 14 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning an attachment layer adjacent to the first cation exchange layer. Optionally, the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer. Step 14 may then be followed by step 18 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer adjacent to the attachment layer. A semi-finished bipolar membrane is assembled.

[0108] Alternatively, in the illustrated embodiment, method 10B begins with step 18 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. Optionally, method 10 begins with step 12 of providing a carrier, followed by step 18. Step 18 may be followed by step 14 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a bonding layer adjacent to the first anion exchange layer. Optionally, the bonding layer comprises a third cation exchange polymer and / or a third anion exchange polymer. Step 14 may then be followed by step 16 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the bonding layer. A semi-finished bipolar membrane is assembled.

[0109] Alternatively, in the illustrated embodiment, method 10C begins with step 14 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a bonding layer. Optionally, the bonding layer includes a third cation exchange polymer and / or a third anion exchange polymer. Optionally, method 10 begins with step 12 of providing a carrier, followed by step 14. Step 14 may be followed by step 16 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the bonding layer, followed by step 20 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer. Step 20 may then be followed by step 18 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer adjacent to the attachment layer, followed by step 22 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer. A semi-finished bipolar membrane is assembled.

[0110] Alternatively, in the illustrated embodiment, method 10D begins with step 14 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a bonding layer. Optionally, the bonding layer includes a third cation exchange polymer and / or a third anion exchange polymer. Optionally, method 10 begins with step 12 of providing a carrier, followed by step 14. Step 14 may be followed by step 18 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer adjacent to the bonding layer, followed by step 22 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer. Then, after step 22, a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer may be electrospun and / or centrifugally spun and / or electrocentrifugally spun adjacent to the attachment layer in step 16, followed by electrospinning and / or centrifugally spun and / or electrocentrifugally spun a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer in step 20. A semi-finished bipolar membrane is assembled.

[0111] Alternatively, in the illustrated embodiment, method 10E begins with step 20 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer. Optionally, method 10 begins with step 12 of providing a carrier, followed by step 20. Step 20 may be followed by step 16 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the second cation exchange layer. Step 16 may then be followed by step 14 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning an attachment layer adjacent to the first cation exchange layer. Optionally, the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer. After step 14, a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer may be electrospun and / or centrifugally spun and / or electrocentrifugally spun adjacent to the attachment layer in step 18, and a second anion exchange layer comprising a second anion exchange polymer may be electrospun and / or centrifugally spun and / or electrocentrifugally spun adjacent to the first anion exchange layer in step 22. A semi-finished bipolar membrane is assembled.

[0112] Alternatively, in the illustrated embodiment, method 10F begins with step 22 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second anion exchange layer comprising a second anion exchange polymer. Optionally, method 10 begins with step 12 of providing a carrier, followed by step 22. Step 22 may be followed by step 18 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer adjacent to the second anion exchange layer. Step 18 may then be followed by step 14 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning an attachment layer adjacent to the first anion exchange layer. Optionally, the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer. Step 14 may be followed by step 16 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the attachment layer, and step 20 of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer. A semi-finished bipolar membrane is assembled.

[0113] This semi-finished bipolar membrane may then be pressed by a pressing step 24, which preferably includes a hot pressing step 26. Step 24 is followed by a conditioning step 28 of the bipolar membrane.

[0114] In a preferred embodiment, steps 14, 16, 18, 20 and 22 are part of a continuous process, and the water splitting catalyst and / or (exchange) polymer are introduced into the semi-finished bipolar membrane using multiple, e.g. double, electrospinning and / or centrifugal spinning and / or electrocentrifugal spinning. Thus, a first spinneret may provide a first water splitting catalyst and a second spinneret may provide a cation exchange polymer, or a first spinneret may provide a cation exchange polymer and a second spinneret may provide an anion exchange polymer, or a first spinneret may provide a second water splitting catalyst and a second spinneret may provide an anion exchange polymer.

[0115] In the illustrated embodiment, the bipolar membrane 100 (FIG. 2) has a bonding layer 102, a first cation exchange layer 104, and a first anion exchange layer 106. The bonding layer 102 has a third cation exchange polymer 108 (a line from the upper left to the lower right) and a third anion exchange polymer 110 (a line from the lower left to the upper right). The first cation exchange layer 104 has a first water splitting catalyst (a cross) and a first cation exchange polymer 114 (a line from the upper left to the lower right). The first anion exchange layer 106 has a second water splitting catalyst 116 (a circle) and a first anion exchange polymer 118 (a line from the lower left to the upper right).

[0116] In the illustrated embodiment, an alternative bipolar membrane 200 (FIG. 3) has a bonding layer 102, a first cation exchange layer 204, a second cation exchange layer 205, a first anion exchange layer 206, and a second anion exchange layer 207. The bonding layer 202 has a third cation exchange polymer 208 (a line from the upper left to the lower right) and a third anion exchange polymer 210 (a line from the lower left to the upper right). The first cation exchange layer 204 has a first water splitting catalyst 212 (a cross) and a first cation exchange polymer 214 (a line from the upper left to the lower right). The second cation exchange layer 205 has a second cation exchange polymer 220. The first anion exchange layer 206 has a second water splitting catalyst 216 (a circle) and a first anion exchange polymer 218 (a line from the lower left to the upper right). The second anion exchange layer 207 has a second cation exchange polymer 222. The water splitting catalysts 212, 216 may be uniformly distributed across their respective layers or may be distributed according to a desired graded distribution, preferably graded transversely to the bonding layer 202.

[0117] In the illustrated embodiment, the bipolar membrane 300 (FIG. 4) has a bonding layer 302, a first cation exchange layer 304, and a first anion exchange layer 206. The bonding layer 302 has a third cation exchange polymer 308 (line from upper left to lower right) and a third anion exchange polymer 310 (line from lower left to upper right). The cation exchange polymer and the anion exchange polymer are preferably the same in the bonding layer 302 and the cation exchange layer 304, and in the bonding layer 302 and the anion exchange layer 306, respectively. The cation exchange layer 304 has a first water splitting catalyst 312 and a cation exchange polymer 308. The anion exchange layer 306 has a second water splitting catalyst 316 and an anion exchange polymer 310. The bipolar membrane 300 further exhibits an increase in the concentration of the first water splitting catalyst 312 and the second water splitting catalyst 316 in the direction toward the bonding layer 302.

[0118] The bipolar membrane according to the invention was tested for its water dissociation ability by electrochemical characterization. +and OH - Catalytic water dissociation to H2O→H + +OH - The results were compared with those of a commercially available bipolar membrane (Fumasep FBM, Fumatech, Germany).

[0119] This commercially available bipolar membrane is, to the best of Applicants' knowledge, the highest performing commercially available bipolar membrane available at the time of this filing.

[0120] Figure 5 shows the bipolar membrane voltage (Volts) versus current density (Am -2 The transmembrane voltage of the bipolar membrane assembled by the method according to the invention was measured using two Ag / AgCl reference electrodes in an aqueous solution of 1 M NaCl at 500 Am. -2 It was lower for the Fumasep bipolar membrane when evaluated at current densities up to

[0121] The bipolar membrane fabricated by the method of the present invention has a resistance of 1000 Am when tested in 1M NaCl. -2 The bipolar membrane fabricated according to the present invention showed a relatively low water dissociation voltage of 100 mV at a current density of 1000 Am -2 In H + and OH - While exhibiting stable behavior for water splitting to 1,000 s, it had a relatively low overpotential of 100 mV compared to the Fumasep bipolar membrane.

[0122] Further experiments revealed water binding curves for bipolar membranes fabricated by the method according to the present invention when tested in 0.5M and 1M HCl and NaOH solutions.

[0123] FIG. 6 shows the voltage drop across a bipolar membrane fabricated by the method of the present invention as water binding occurs when the bipolar membrane is tested with corresponding HCl and NaOH concentrations across the bipolar membrane.

[0124] The system according to the invention can be used for energy storage, for example using a pH gradient system. Furthermore, stacking different cells with bipolar membranes according to the invention can result in increased storage capacity and increased stack voltage.

[0125] The present invention is in no way limited to the preferred embodiments and / or experiments thereof described above. The claimed subject matter is defined by the appended claims, within whose scope many modifications are possible.

Claims

1. 1. A method of assembling a bipolar membrane, comprising: - electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer; - electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the bonding layer, and - electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer; The process includes the steps of: the first cation exchange layer and the second anion exchange layer are provided adjacent to and on opposite sides of the bonding layer; method.

2. 2. The method of claim 1, further comprising the steps of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning a second cation exchange layer comprising a second cation exchange polymer, and / or electrospinning and / or centrifugally spinning a second anion exchange layer comprising a second anion exchange polymer.

3. 3. The method of claim 1 or 2, wherein the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first cation exchange layer and / or the step of electrospinning and / or centrifugally spinning and / or electrocentrifugally spinning the first anion exchange layer comprises electrospraying the first water splitting catalyst and / or the second water splitting catalyst in a stepwise manner.

4. The method of claim 3 , wherein a concentration of the first water splitting catalyst and / or the second water splitting catalyst decreases in a direction extending from adjacent bonding layers.

5. The method according to any one of claims 1 to 4, wherein the first water splitting catalyst and the second water splitting catalyst are independently selected from one or more of a porous silica material, an aluminum silicate, a zeolite, and an organic catalyst.

6. 6. The method of claim 5, wherein the organic catalyst is one or more selected from the group consisting of poly(4-vinylphenol), polyethylene glycol.

7. The first water splitting catalyst and the second water splitting catalyst are MCM-41, TiO ２ , IrO ２ , Al(OH) ３ , graphene oxide, graphite oxide, ZIF-7, ZIF-8, ZIF-90, MOF-5, IRMOF-1, HKUST-1, CuTPA, SiO ２ , Mn(HCOO) ２ The method according to any one of claims 1 to 6, wherein the compound is one or more independently selected from the group consisting of:

8. The method of claim 7, wherein the first water splitting catalyst and / or the second water splitting catalyst is MCM-41.

9. The method of any one of claims 1 to 8, wherein the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer.

10. 10. The method of any one of claims 1 to 9, wherein each cation exchange polymer is independently one or more selected from the group consisting of sulfonated polyetheretherketone, copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone.

11. The method of any one of claims 1 to 10, wherein each anion exchange polymer is independently one or more selected from the group consisting of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3.

12. 12. The method of claim 10 and / or 11, wherein each cation exchange polymer is a sulfonated polyetheretherketone and / or each anion exchange polymer is FAA-3.

13. 13. The method of any one of claims 1 to 12, wherein each of the one or more cation exchange polymers and each of the one or more anion exchange polymers are dissolved and / or dispersed in a solvent and / or dispersion medium, and for each exchange polymer, the solvent and / or dispersion medium is one or more independently selected from the group: dimethylacetamide, dimethylformamide, propanol, dimethylsulfoxide, N-methyl-2-pyrrolidone.

14. The method according to any one of claims 1 to 13, wherein the first water splitting catalyst and the second water splitting catalyst are dissolved and / or dispersed in a solvent and / or a dispersion medium, and for each water splitting catalyst, the solvent and / or dispersion medium is one or more independently selected from the group consisting of water, methanol, ethanol, and propanol.

15. The method according to any one of claims 1 to 14, further comprising a pressing step, preferably wherein the pressing step comprises a hot pressing step.

16. 16. The method according to claim 15, wherein the step of hot pressing is carried out at a temperature in the range of 120°C to 180°C, preferably in the range of 130°C to 170°C, more preferably in the range of 140°C to 160°C, and most preferably at a temperature of about 150°C.

17. 17. The method according to claim 15 or 16, wherein the step of hot pressing is carried out at a pressure in the range of 150 bar to 250 bar, preferably at a pressure of 175 bar to 225 bar, more preferably at a pressure of 195 bar to 205 bar, most preferably at a pressure of about 200 bar.

18. 18. The method according to claim 15, 16 or 17, wherein the step of hot pressing is carried out for a period of up to 2 hours, preferably for a period of 0.1 hours to 2 hours, more preferably for a period of 0.1 hours to 1.5 hours, even more preferably for a period of 0.1 hours to 1 hour and most preferably for a period of 0.1 hours to 0.25 hours.

19. The method of any one of claims 1 to 18, further comprising conditioning the bipolar membrane.

20. 20. The method of claim 19, wherein the conditioning step is carried out in an aqueous solution of sodium chloride at a concentration ranging from 0.5M to 1.5M, preferably at a concentration ranging from 0.75M to 1.25M, more preferably at a concentration of about 1M.

21. A bipolar membrane, - bonding layer, a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer, the first cation exchange layer being assembled adjacent to the attachment layer; and a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer, the first anion exchange layer being assembled adjacent to the bonding layer; having A bipolar membrane, wherein the first cation exchange layer has a concentration of the first water splitting catalyst and / or the first anion exchange layer has a concentration of the second water splitting catalyst, which concentrations vary in a direction extending from the adjacent bonding layer.

22. and / or a second cation exchange layer comprising a second cation exchange polymer, said second cation exchange layer being assembled adjacent to said first cation exchange layer. a second anion exchange layer comprising a second anion exchange polymer, the second anion exchange layer being assembled adjacent to the first anion exchange layer; 22. The bipolar membrane of claim 21.

23. The first water splitting catalyst and the second water splitting catalyst are MCM-41, TiO ２ , IrO ２ , Al(OH) ３ , graphene oxide, graphite oxide, ZIF-7, ZIF-8, ZIF-90, MOF-5, IRMOF-1, HKUST-1, CuTPA, SiO ２ , Mn(HCOO) ２ 23. The bipolar membrane of claim 21 or 22, wherein the first and second electrodes are independently selected from the group consisting of:

24. The bipolar membrane of any one of claims 21 to 23, wherein the attachment layer comprises a third cation exchange polymer and / or a third anion exchange polymer.

25. 25. The bipolar membrane of any one of claims 21 to 24, wherein each cation exchange polymer is independently one or more selected from the group consisting of sulfonated polyetheretherketone, copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), and sulfonated polyethersulfone.

26. 26. The bipolar membrane of any one of claims 21 to 25, wherein each anion exchange polymer is independently one or more selected from the group consisting of quaternized poly(p-phenylene oxide), quaternized polyepichlorohydrin, poly(spirobiindane-arylethersulfone) copolymer, polyethylene oxide, quaternized polyethersulfone, FAA-3.

27. Bipolar membrane according to any one of claims 21 to 26, obtainable by the method according to any one of claims 1 to 20.

28. A bipolar membrane obtainable by the method according to any one of claims 1 to 20.

29. Use of a bipolar membrane according to any one of claims 21 to 28 in hydrogen production, acid based flow batteries, fuel cells, carbon dioxide capture and / or inorganic and / or organic acid based production and / or recovery.

30. 30. The use of a bipolar membrane according to claim 29, wherein the bipolar membrane has an overvoltage of at least 1000 Am －２ , having a current density of .

31. A system comprising a bipolar membrane according to any one of claims 21 to 28.

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