Apparatus for removal of ions from water and method of producing the same

1. An apparatus for removal of ions from water, the apparatus comprising:

a carbon coated first current collector;

a second current collector;

a spacer in between the first and second current collectors to allow water to flow through the spacer in between the first and second current collectors;

a first charge barrier in between the carbon coated first current collector and the spacer to selectively allow anions or cations to flow through the first charge barrier; and

a second charge barrier coated onto the carbon coated first current collector and in contact with the first charge barrier, the second charge barrier being between 1 to 40 microns thick.

2. The apparatus according to claim 1 , wherein the second current collector is coated with carbon and a third charge barrier is provided in between the carbon coated second current collector and the spacer to selectively transport anions or cations to flow through the third charge barrier.

3. The apparatus according to claim 1 , wherein the first charge barrier is configured to block cations from passing through the first charge barrier while allowing anions to pass through the first charge barrier and the second charge barrier is configured to block cations from passing through the second charge barrier while allowing anions to pass through the second charge barrier, or

wherein the first charge barrier is configured to block anions from passing through the first charge barrier while allowing cations to pass through the first charge barrier and the second charge barrier is configured to block anions from passing through the second charge barrier while allowing cations to pass through the second charge barrier.

4. The apparatus according to claim 1 , wherein the first charge barrier is between 10 to 400 microns thick.

5. The apparatus according to claim 1 , wherein the second charge barrier is between 1 to 20 microns thick.

6. The apparatus according to claim 1 , wherein the first charge barrier comprises a different material than the second charge barrier.

7. The apparatus according to claim 1 , wherein the first current collector functions as an anode and is provided with the first charge barrier, which is configured to block cations from passing through the first charge barrier while allowing anions to pass through the first charge barrier, and with the second charge barrier, which is configured to block cations from passing through the second charge barrier while allowing anions to pass through the second charge barrier.

8. The apparatus according to claim 1 , wherein the first current collector functions as a cathode and is provided with the first charge barrier, which is configured to block anions from passing through the first charge barrier while allowing cations to pass through the first charge barrier, and with the second charge barrier, which is configured to block anions from passing through the second charge barrier while allowing cations to pass through the second charge barrier.

9. The apparatus according to claim 1 , wherein the first charge barrier comprises a fiber structure for reinforcement.

10. The apparatus according to claim 1 , wherein the first and second charge barriers comprise the same material.

11. The apparatus according to claim 1 , wherein the second current collector is coated with a charge barrier.

12. The apparatus according to claim 1 , wherein the first and second charge barriers are separate layers assembled together in a stack.

13. The apparatus according to claim 1 , wherein the second charge barrier comprises polyepichlorochidrin, poly(4-vinyl pyridine-co-styrene) or sulfonated polyether ether ketone.

14. The apparatus according to claim 1 , wherein the second charge barrier provides a substantially flat and smooth surface to improve the contact with the first charge barrier.

15. A method of producing an apparatus for removal of ions from water of claim 1 , the method comprising:

coating a second charge barrier onto a carbon coated first current collector, the second charge barrier being between 1 to 40 microns thick;

providing a first charge barrier in contact with the second charge barrier to selectively allow anions or cations to flow through the first charge barrier;

providing a spacer in contact with the first charge barrier; and

providing a second current collector against the spacer, the spacer between the first and second current collectors arranged to allow water to flow through the spacer in between the first and second current collectors.

16. The method according to claim 15 , wherein the first charge barrier is pressed against the second charge barrier.

17. The method according to claim 15 , further comprising coating the carbon onto the first current collector.

18. The method according to claim 15 , wherein the first charge barrier is configured to block cations from passing through the first charge barrier while allowing anions to pass through the first charge barrier and the second charge barrier is configured to block cations from passing through the second charge barrier while allowing anions to pass through the second charge barrier, or

wherein the first charge barrier is configured to block anions from passing through the first charge barrier while allowing cations to pass through the first charge barrier and the second charge barrier is configured to block anions from passing through the second charge barrier while allowing cations to pass through the second charge barrier.

19. The method according to claim 15 , wherein the second current collector is coated with carbon and a third charge barrier is provided in between the carbon coated second current collector and the spacer to selectively transport anions or cations to flow through the third charge barrier.

20. The method according to claim 15 , wherein the first charge barrier comprises a different material than the second charge barrier.