METHOD FOR ASSEMBLING A BIPOLAR MEMBRANE, BIPOLAR MEMBRANE, AND USE OF SAID BIPOLAR MEMBRANE

Abstract

The invention relates to a method for assembling a bipolar membrane, and bipolar membrane thereof. The method comprises the steps of electrospinning and centrifugal spinning and electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer, electrospinning and centrifugal spinning and electrocentrifugal spinning a junction layer. Further, the method comprises electrospinning and centrifugal spinning and electrocentrifugal spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. A system comprising a bipolar membrane according to the invention is also disclosed.

Claims

1. A method for assembling a bipolar membrane, the method comprising: at least one of electrospinning, centrifugal spinning, and electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer; at least one of electrospinning, centrifugal spinning, and electrocentrifugal spinning a junction layer; and at least one of electrospinning, centrifugal spinning, and electrocentrifugal spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer, wherein the first cation exchange layer and the second anion exchange layer are provided adjacent to and on opposite sides of the junction layer.

2. The method of claim 1 further comprising at least one of electrospinning, centrifugal spinning, and electrocentrifugal spinning a second cation exchange layer comprising at least one of a second cation exchange polymer, and at least one of electrospinning, centrifugal spinning, and electrocentrifugal spinning a second anion exchange layer comprising a second anion exchange polymer.

3. The method of claim 1, wherein at least one of electrospinning, centrifugal spinning, electrocentrifugal spinning a first cation exchange layer, and at least one of electrospinning, centrifugal spinning, and electrocentrifugal spinning a first anion exchange layer comprises at least one of gradually electrospraying the first water splitting catalyst and the second water splitting catalyst.

4. The method of claim 3, wherein a concentration of at least one of the first water splitting catalyst and the second water splitting catalyst declines in a direction extending from the adjacent junction layer.

5. The method of claim 1, wherein the first water splitting catalyst and the second water splitting catalyst are one or more independently selected from a group of porous silica materials, aluminium silicates, zeolites, organic catalysts.

6. (canceled)

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

8. (canceled)

9. The method of claim 1, wherein the junction layer comprises at least one of a third cation exchange polymer and a third anion exchange polymer.

10. The method of claim 1, wherein each cation exchange polymer is one or more independently selected from a group of sulfonated poly-ether ether ketone, a copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), sulfonated polyether sulfone and wherein each anion exchange polymer is one or more independently selected from a group of quaternized poly(p-phenylene oxide), quaternized polyepichlorhydrine, poly(spirobiindane-aryl ether sulfone) copolymers, polyethylene oxide, quaternized polyether sulfone, FAA-3.

11. (canceled)

12. The method of 1, wherein each of one or more cation exchange polymer and each of one or more anion exchange polymer are at least one of dissolved and dispersed in at least one of a solvent and a dispersant, wherein, for each exchange polymer, at least one of the solvent and the dispersant is one or more independently selected from a group of dimethylacetamide, dimethylformamide, propanol, dimethyl sulfoxide, and N-methyl-2-pyrrolidone.

13. (canceled)

14. The method of claim 1, wherein the first water splitting catalyst and the second water splitting catalyst are at least one of dissolved and dispersed in at least one of a solvent and a dispersant, wherein, for each water splitting catalyst, at least one of the solvent and the dispersant is one or more independently selected from a group of water, methanol, ethanol, propanol.

15. The method claim 1, further comprising pressing, wherein the pressing comprises hot-pressing.

16. The method of claim 10, wherein the hot-pressing is performed at a temperature in a range of 120 C. to 180 C., and wherein the hot-pressing is performed at a pressure in a range of 150 bar to 250 bar, and wherein the step of hot-pressing is performed for a period of at most 2 hours.

17. (canceled)

18. (canceled)

19. The method of claim 1, further comprising conditioning the bipolar membrane, wherein the conditioning is performed in an aqueous solution of sodium chloride comprising a concentration in a range of 0.5 M to 1.5 M.

20. (canceled)

21. A bipolar membrane comprising: a junction layer; a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer, wherein the first cation exchange layer is assembled adjacent to the junction layer; and a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer, wherein the first anion exchange layer is assembled adjacent to the junction layer, wherein at least one of the first cation exchange layer comprises a concentration of the first water splitting catalyst and the first anion exchange layer comprises a concentration of the second water splitting catalyst which varies in a direction extending from the adjacent junction layer.

22. The bipolar membrane of claim 21, further comprising a second cation exchange layer comprising a second cation exchange polymer, wherein the second cation exchange layer is assembled adjacent to at least one of the first cation exchange layer and a second anion exchange layer comprising a second anion exchange polymer, wherein the second anion exchange layer is assembled adjacent to the first anion exchange layer.

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

24. The bipolar membrane of claim 21, wherein the junction layer comprises at least one of a third cation exchange polymer and and/or a third anion exchange polymer.

25. The bipolar membrane of claim 21, wherein each of the first cation exchange polymer and the second cation exchange polymer is at least one of, independently selected from a group of, sulfonated poly-ether ether ketone, a copolymer of poly(tetrafluoroethylene) and polysulfonyl fluoride vinyl ether, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide), sulfonated polyether sulfone, and wherein each anion exchange polymer is one or more independently selected from a group of quaternized poly(p-phenylene oxide), quaternized polyepichlorhydrine, poly(spirobiindane-aryl ether sulfone) copolymers, polyethylene oxide, quaternized polyether sulfone, FAA-3.

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

Description

[0121] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

[0122] FIG. 1 shows a schematic overview of a method according to the invention;

[0123] FIG. 2 shows a schematic overview of a bipolar membrane according to the invention comprising a junction layer, first cation exchange layer, and a first anion exchange layer;

[0124] FIG. 3 shows a schematic overview of an alternative bipolar membrane according to the invention comprising a junction layer, first and second cation exchange layer, and a first and second anion exchange layer;

[0125] FIG. 4 shows a schematic overview of a further alternative bipolar membrane according to the invention comprising gradually electro sprayed first water splitting catalyst and second water splitting catalyst;

[0126] FIG. 5 shows the current density versus bipolar membrane voltage of the bipolar membrane according to the invention and a conventional bipolar membrane; and

[0127] FIG. 6 shows a water association curve for the invented bipolar membrane as tested in 0.5 M and 1 M HCl and NaOH solutions.

[0128] Method 10 (FIG. 1) for assembling a bipolar membrane follows a sequence of different steps.

[0129] In the illustrated embodiment method 10A starts with step 16 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer. Optionally, method 10 starts with step 12 of providing a carrier followed by step 16. Step 16 may be followed by step 14 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a junction layer adjacent to the first cation exchange layer. Optionally, the junction 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 centrifugal spinning and/or electrocentrifugal spinning a first anion exchange layer comprising an second water splitting catalyst and a first anion exchange polymer adjacent to the junction layer. To assemble a semi-finished bipolar membrane.

[0130] Alternatively, in the illustrated embodiment method 10B starts with step 18 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer. Optionally, method 10 starts with step 12 of providing a carrier followed by step 18. Step 18 may be followed by step 14 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a junction layer adjacent to the first anion exchange layer. Optionally, the junction 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 centrifugal spinning and/or electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the junction layer. To assemble a semi-finished bipolar membrane.

[0131] Alternatively, in the illustrated embodiment method 10C starts with step 14 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a junction layer. Optionally, the junction layer comprises a third cation exchange polymer and/or a third anion exchange polymer. Optionally, method 10 starts with step 12 of providing a carrier followed by step 14. Step 14 may be followed by step 16 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the junction layer, followed by step 20 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer. Step 20 may than be followed by step 18 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first anion exchange layer comprising a second water slitting catalyst and a first anion exchange polymer adjacent to the junction layer, and followed by step 22 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer. To assemble a semi-finished bipolar membrane.

[0132] Alternatively, in the illustrated embodiment method 10D starts with step 14 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a junction layer. Optionally, the junction layer comprises a third cation exchange polymer and/or a third anion exchange polymer. Optionally, method 10 starts with step 12 of providing a carrier followed by step 14. Step 14 may be followed by step 18 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer adjacent to the junction layer, and followed by step 22 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer. Step 22 may than be followed by step 16 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first a first cation exchange polymer adjacent to the junction layer, followed by step 20 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer. To assemble a semi-finished bipolar membrane.

[0133] Alternatively, in the illustrated embodiment method 10E starts with step 20 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second cation exchange layer comprising a second cation exchange polymer. Optionally, method 10 starts with step 12 of providing a carrier followed by step 20. Step 20 may be followed by step 16 of electrospinning and/or centrifugal spinning and/or electrocentrifugal 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. Then, step 16 may be followed by step 14 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a junction layer adjacent to the first cation exchange layer. Optionally, the junction layer comprises a third cation exchange polymer and/or a third anion exchange polymer. Step 14 may be followed by step 18 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a first anion exchange layer comprising a second water splitting catalyst and a first anion exchange polymer adjacent to the junction layer, and step 22 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second anion exchange layer comprising a second anion exchange polymer adjacent to the first anion exchange layer. To assemble a semi-finished bipolar membrane.

[0134] Alternatively, in the illustrated embodiment method 10F starts with step 22 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second anion exchange layer comprising a second anion exchange polymer. Optionally, method 10 starts with step 12 of providing a carrier followed by step 22. Step 22 may be followed by step 18 of electrospinning and/or centrifugal spinning and/or electrocentrifugal 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. Then, step 18 may be followed by step 14 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a junction layer adjacent to the first anion exchange layer. Optionally, the junction 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 centrifugal spinning and/or electrocentrifugal spinning a first cation exchange layer comprising a first water splitting catalyst and a first cation exchange polymer adjacent to the junction layer, and step 20 of electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning a second cation exchange layer comprising a second cation exchange polymer adjacent to the first cation exchange layer. To assemble a semi-finished bipolar membrane.

[0135] The assembled semi-finished bipolar membrane may than be pressed by step 24 of pressing, wherein step 24 preferably comprises step 26 of step of hot-pressing. Step 24 is followed by step 28 of conditioning the bipolar membrane.

[0136] In a preferred embodiment, the steps 14, 16, 18, 20, and 22 are part of a continuous process, wherein the water splitting catalysts and/or (exchange) polymers are included in the semi-finished bipolar membrane using multiple, such as dual, electrospinning and/or centrifugal spinning and/or electrocentrifugal spinning. Therefore, a first spinneret may provide the first water splitting catalyst and a second spinneret may provide the cation exchange polymer, or a first spinneret may provide the cation exchange polymer and a second spinneret may provide the anion exchange polymer, or a first spinneret may provide the second water splitting catalyst and a second spinneret may provide the anion exchange polymer.

[0137] In an illustrated embodiment bipolar membrane 100 (FIG. 2) comprises junction layer 102, first cation exchange layer 104, and first anion exchange layer 106. Junction layer 102 comprises third cation exchange polymer 108 (lines from left top to right bottom) and third anion exchange polymer 110 (lines from left bottom to right top). First cation exchange layer 104 comprises first water splitting catalyst 112 (crosses) and first cation exchange polymer 114 (lines from left top to right bottom). First anion exchange layer 106 comprises second water splitting catalyst 116 (circles) and first anion exchange polymer 118 (lines from left bottom to right top).

[0138] In an illustrated embodiment, alternative bipolar membrane 200 (FIG. 3) comprises junction layer 202, first cation exchange layer 204, second cation exchange layer 205, first anion exchange layer 206, and second anion exchange layer 207. Junction layer 202 comprises third cation exchange polymer 208 (lines from left top to right bottom) and third anion exchange polymer 210 (lines from left bottom to right top). First cation exchange layer 204 comprises first water splitting catalyst 212 (crosses) and first cation exchange polymer 214 (lines from left top to right bottom). Second cation exchange layer 205 comprises second cation exchange polymer 220. First anion exchange layer 206 comprises second water splitting catalyst 216 (circles) and first anion exchange polymer 218 (lines from left bottom to right top). Second anion exchange layer 207 comprises second cation exchange polymer 222. Water splitting catalysts 212, 216 are homogenously distributed over the respective layers or are distributed according to a desired distribution having a gradient, preferably in a direction transversal to junction layer 202.

[0139] In an illustrated embodiment bipolar membrane 300 (FIG. 4) comprises junction layer 302, first cation exchange layer 304, and first anion exchange layer 306. Junction layer 302 comprises third cation exchange polymer 308 (lines from left top to right bottom) and third anion exchange polymer 310 (lines from left bottom to right top). The cation exchange polymer and anion exchange polymer are preferably the same in junction layer 302 and cation exchange layer 304, and junction layer 302 and anion exchange layer 306 respectively. Cation exchange layer 304 comprises first water splitting catalyst 312 and cation exchange polymer 308. Anion exchange layer 306 comprises second water splitting catalyst 316 and anion exchange polymer 310. Bipolar membrane 300 further shows an increasing concentration of first water splitting catalyst 312 and second water splitting catalyst 316 towards junction layer 302.

[0140] The bipolar membrane according to the invention has been tested for its capability of water dissociation by means of electrochemical characterization. The bipolar membrane assembled with the method according to the invention has been compared in terms of the catalytic water dissociation in H.sup.+ and OH.sup. following:

H.sub.2O.fwdarw.H.sup.++OH

[0141] with commercially available bipolar membranes (Fumasep FBM, Fumatech GmbH, Germany).

[0142] This commercially available bipolar membrane is, to the best of our knowledge, the best performing commercially available bipolar membrane at the time of filing.

[0143] FIG. 5 shows the bipolar membrane voltage (Volt) versus current density (A m.sup.2). The bipolar membrane transmembrane voltage of the bipolar membrane assembled with the method according to the invention was lower than for the Fumasep bipolar membrane as characterized in an aqueous solution of 1 M NaCl using two Ag/AgCl reference electrodes and up to a current density of 500 A m.sup.2.

[0144] The bipolar membrane assembled with the method according to the invention showed a lower water dissociation voltage of 100 mV compared to the commercially available Fumasep bipolar membrane at 1000 A m.sup.2 as tested in 1 M NaCl. The bipolar membrane assembled with the method according to the invention showed a stable behaviour for water splitting in H.sup.+ and OH at a current density of 1000 A m.sup.2 while having a lower overpotential of 100 mV compared to Fumasep bipolar membrane.

[0145] Further experiments showed a water association curve for the bipolar membrane assembled with the method according to the invention as tested in 0.5 M and 1 M HCl and NaOH solutions. FIG. 6 presents the voltage drop across the bipolar membrane assembled with the method according to the invention when water combination occurs when testing the bipolar membrane with corresponding HCl and NaOH concentrations across the bipolar membrane.

[0146] The system according to the invention may be used for the storage of energy, for example for storage of energy using a pH gradient system. In addition, stacking different cells comprising the bipolar membrane according to the invention results in an increase in storage capacity and stack voltage.

[0147] The present invention is by no means limited to the above described preferred embodiments and/or experiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.