Catalyst-coated membrane having a laminate structure
A catalyst-coated membrane (CCM) for use in a water electrolyser, having a laminate structure comprising: a first layer comprising a first membrane component having a cathode catalyst layer disposed on a first face thereof; a second layer comprising a second membrane component having an anode catalyst layer disposed on a first face thereof; and an intermediate layer disposed between the first and second layers, comprising a third membrane component having a recombination catalyst layer disposed on a first face thereof is disclosed. The CCM is useful within a water electrolyser. The recombination catalyst layer reduces the risk associated with hydrogen crossover and allows thinner membranes with lower resistance to be used.
1. A catalyst-coated membrane for use in a water electrolyser, having a laminate structure comprising:
a first layer comprising a first membrane component, the first membrane component having a cathode catalyst layer disposed on a first face thereof;
a second layer comprising a second membrane component, the second membrane component having an anode catalyst layer disposed on a first face thereof; and
an intermediate layer disposed between the first and second layers, comprising a third membrane component,
wherein only a single face of the first membrane component has a catalyst layer thereon, and only a single face of the third membrane component has a catalyst layer thereon, the catalyst layer on the single face of the third membrane component is a recombination catalyst layer, and the recombination catalyst layer is located closer to the anode catalyst layer than to the cathode catalyst layer within the catalyst-coated membrane, and,
wherein the first membrane component comprises an embedded reinforcing component and the third membrane component does not include an embedded reinforcing component.
2. The catalyst-coated membrane according to claim 1 , wherein the first and second layers are each adjacent the intermediate layer.
3. The catalyst-coated membrane according to claim 1 , wherein
a second face of the first membrane component is adjacent the intermediate layer and a second face of the second membrane component is adjacent the intermediate layer, and the intermediate layer is oriented such that the recombination catalyst layer is disposed adjacent the second layer.
4. The catalyst-coated membrane according to claim 1 , wherein the catalyst coated membrane has a total thickness of ≤120 μm.
5. The catalyst-coated membrane according to of claim 1 , wherein the first, second and third membrane components are solid polymer electrolyte membrane components comprising an ionomer.
6. The catalyst-coated membrane according to claim 1 , wherein one or more of the first, second and third membrane components further comprise a peroxide removal additive or a peroxy radical scavenger.
7. The catalyst-coated membrane according to claim 1 , wherein the cathode catalyst comprises unsupported platinum black or platinum supported on carbon.
8. The catalyst-coated membrane according to claim 1 , wherein the anode catalyst is selected from unsupported iridium oxide black or iridium on a support.
9. The catalyst-coated membrane according to any one of claim 1 , wherein the recombination catalyst is selected from palladium on carbon, platinum on carbon, rhodium on carbon and platinum-group metal on silica.
10. The catalyst-coated membrane according to claim 1 consisting of the following layers, in order:
(a) the cathode catalyst layer comprising a cathode catalyst;
(b) the first membrane component;
(c) the third membrane component;
(d) the recombination catalyst layer comprising a recombination catalyst;
(e) the second membrane component; and
(f) the anode catalyst layer comprising an anode catalyst.
11. A method of making a catalyst-coated membrane according to claim 1 comprising:
providing the first membrane component, the first membrane component having the cathode catalyst layer disposed on the first face of the first membrane component;
providing the second membrane component, the second membrane component having the anode catalyst layer disposed on the first face of the second membrane component;
providing the third membrane component, the third membrane component having the recombination catalyst layer disposed on the first face of the third membrane component; and
laminating the first, second and third membrane components together to form a catalyst-coated membrane having a laminate structure, such that the third membrane component is disposed between the first and second membrane components within the laminate structure.
12. The method according to claim 11 , wherein the first, second and third membrane components are laminated together in a single lamination step.
13. The method according to claim 11 , wherein before lamination the membrane component are arranged such that a second face of the first membrane component faces a second face of the third membrane component and a second face of the second membrane faces the first face of the third membrane component.
14. A catalyst-coated membrane obtained by the method according to claim 11 .
15. A water electrolyser comprising the catalyst-coated membrane according to claim 1 .
16. A fuel cell comprising the catalyst-coated membrane according to claim 1 .
17. A method of generating hydrogen gas comprising the steps of electrolysing water using the water electrolyser according to claim 15 , and generating hydrogen gas.