Modular electrochemical cells

1. A gas diffusion electrode for an electro-synthetic or electro-energy cell, comprising:

one or more gas permeable layers;

a first conductive layer provided on a first side of the gas diffusion electrode, wherein the first conductive layer comprises a porous conductive material; and

a second layer provided on a second side of the gas diffusion electrode;

wherein the one or more gas permeable layers provide a gas channel, and the one or more gas permeable layers are positioned between the first conductive layer and the second layer.

2. The electrode of claim 1 , wherein the second layer provides a second conductive layer.

3. The electrode of claim 2 , wherein the second conductive layer comprises a porous conductive material.

4. The electrode of claim 1 , wherein the porous conductive material is a porous metallic material.

5. The electrode of claim 1 , wherein, in use, the first side of the gas diffusion electrode and the second side of the gas diffusion electrode contact a liquid electrolyte.

6. The electrode of claim 5 , wherein the one or more gas permeable layers are gas permeable and impermeable to the liquid electrolyte.

7. The electrode of claim 1 , wherein the porous conductive material is gas permeable and liquid electrolyte permeable.

8. The electrode of claim 1 , wherein there are two or more gas permeable layers.

9. The electrode of claim 1 , comprising a spacer positioned between the first conductive layer and the second layer.

10. The electrode of claim 9 , wherein the spacer is a different material to the one or more gas permeable layers.

11. The electrode of claim 1 , wherein the gas diffusion electrode is a double-sided electrode.

12. The electrode of claim 11 , further comprising an electrolyte spacer positioned between adjacent gas diffusion electrodes.

13. The electrode of claim 12 , wherein a liquid electrolyte can move through the electrolyte spacer.

14. The electrode of claim 1 , wherein the first conductive layer and/or the second layer are provided adjacent to or on the one or more gas permeable layers.

15. The electrode of claim 1 , wherein the first conductive layer and/or the second layer are deposited on the one or more gas permeable layers.

16. The electrode of claim 1 , wherein the gas channel is able to transport gas internally in the gas diffusion electrode.

17. The electrode of claim 1 , wherein the one or more gas permeable layers are formed from a gas permeable material.

18. The electrode of claim 17 , wherein the gas permeable material is selected from the group of PTFE, ePTFE, polypropylene, polyethylene, polyethersulfone and polysulfone.

19. The electrode of claim 9 , wherein the one or more gas permeable layers and the spacer are contiguous.

20. The electrode of claim 12 , wherein a gas is extracted or introduced in the gas channel that is substantially parallel to an electrolyte channel provided by the electrolyte spacer.

21. The electrode of claim 20 , wherein the gas is extracted or introduced in one direction and a second gas is extracted or introduced in another direction via a second gas channel in a second gas diffusion electrode.

22. The electrode of claim 21 , wherein the electrolyte channel is separate from the gas channel and is positioned between the gas diffusion electrode and the second gas diffusion electrode.

23. The electrode of claim 9 , wherein the spacer is flexible.

24. The electrode of claim 9 , wherein the spacer is a non-conductive polymer, a polyolefin mesh, an electrically insulating polymer net or is provided by embossed polymer structures.

25. The electrode of claim 1 , wherein bubbles of gas are not produced at the gas diffusion electrode.

26. The electrode of claim 1 , wherein the gas diffusion electrode includes a barrier layer, and the barrier layer limits an amount of an undesired gas permeating through the gas diffusion electrode.

27. A gas diffusion electrode for an electro-synthetic or electro-energy cell, comprising:

one or more gas permeable layers;

a first conductive layer provided on a first side of the gas diffusion electrode;

a second layer provided on a second side of the gas diffusion electrode; and

a spacer positioned between the first conductive layer and the second layer;

wherein the one or more gas permeable layers provide a gas channel, and the one or more gas permeable layers are positioned between the first conductive layer and the second layer, and the spacer forms at least part of the gas channel.

28. The electrode of claim 27 , wherein the first conductive layer comprises a porous conductive material.

29. The electrode of claim 27 , wherein the second layer provides a second conductive layer.

30. The electrode of claim 29 , wherein the second conductive layer comprises a porous conductive material.

31. The electrode of claim 28 , wherein the porous conductive material is a porous metallic material.

32. The electrode of claim 27 , wherein, in use, the first side of the gas diffusion electrode and the second side of the gas diffusion electrode contact a liquid electrolyte.

33. The electrode of claim 32 , wherein the one or more gas permeable layers are gas permeable and impermeable to the liquid electrolyte.

34. The electrode of claim 28 , wherein the porous conductive material is gas permeable and liquid electrolyte permeable.

35. The electrode of claim 27 , wherein there are two or more gas permeable layers.

36. The electrode of claim 27 , wherein the spacer is a different material to the one or more gas permeable layers.

37. The electrode of claim 27 , wherein the gas diffusion electrode is a double-sided electrode.

38. The electrode of claim 37 , further comprising an electrolyte spacer positioned between adjacent gas diffusion electrodes.

39. The electrode of claim 38 , wherein a liquid electrolyte can move through the electrolyte spacer.

40. The electrode of claim 27 , wherein the first conductive layer and/or the second layer are provided adjacent to or on the one or more gas permeable layers.

41. The electrode of claim 27 , wherein the first conductive layer and/or the second layer are deposited on the one or more gas permeable layers.

42. The electrode of claim 27 , wherein the gas channel is able to transport gas internally in the gas diffusion electrode.

43. The electrode of claim 27 , wherein the one or more gas permeable layers are formed from a gas permeable material.

44. The electrode of claim 43 , wherein the gas permeable material is selected from the group of PTFE, ePTFE, polypropylene. polyethylene, polyethersulfone and polysulfone.

45. The electrode of claim 27 , wherein the one or more gas permeable layers and the spacer are contiguous.

46. The electrode of claim 38 , wherein a gas is extracted or introduced in the gas channel that is substantially parallel to an electrolyte channel provided by the electrolyte spacer.

47. The electrode of claim 46 , wherein the gas is extracted or introduced in one direction and a second gas is extracted or introduced in another direction via a second gas channel in a second gas diffusion electrode.

48. The electrode of claim 47 , wherein the electrolyte channel is separate from the gas channel and is positioned between the gas diffusion electrode and the second gas diffusion electrode.

49. The electrode of claim 27 , wherein the spacer is flexible.

50. The electrode of claim 27 , wherein the spacer is a non-conductive polymer, a polyolefin mesh, an electrically insulating polymer net or is provided by embossed polymer structures.

51. The electrode of claim 27 , wherein bubbles of gas are not produced at the gas diffusion electrode.

52. The electrode of claim 27 , wherein the gas diffusion electrode includes a barrier layer, and the barrier layer limits an amount of an undesired gas permeating through the gas diffusion electrode.