Electrochemical cell with gap between electrode and membrane, and methods to use and manufacture thereof

1. An electrochemical cell, comprising:

a first electrode;

a membrane disposed adjacent to the electrode, wherein the first electrode and the membrane are separated by a first membrane-electrode gap; and

one or more first spacers disposed in the first membrane-electrode gap between the first electrode and the membrane,

wherein the one or more first spacers comprise one or more first features extending in a first direction and one or more second features extending in a second direction, wherein the first direction is different from the second direction, and wherein a thickness of at least a portion of the one or more first features is greater than a corresponding thickness of at least a corresponding portion of the one more second features to form one or more pathways for flow of electrolyte or gas or both through the one or more spacers.

2. The electrochemical cell of claim 1 , wherein the first membrane-electrode gap is from about 0.2 mm to about 2 mm.

3. The electrochemical cell of claim 1 , further comprising a second electrode disposed adjacent to an opposite side of the membrane from the first electrode, wherein the first electrode and the second electrode are separated by a fixed gap of from about 0.2 mm to about 4 mm.

4. The electrochemical cell of claim 3 , further comprising one or more second spacers disposed in a second membrane-electrode gap between the second electrode and the membrane.

5. The electrochemical cell of claim 4 , wherein the one or more second spacers are in direct contact with the second electrode and the membrane.

6. The electrochemical cell of claim 1 , wherein the first electrode is a planar electrode or an expanded metal or a mesh and the membrane is an anion exchange membrane or a cation exchange membrane.

7. The electrochemical cell of claim 1 , wherein the one or more first spacers occupy the first membrane-electrode gap partially.

8. The electrochemical cell of claim 1 , wherein the one or more first spacers are in direct contact with the first electrode and the membrane.

9. The electrochemical cell of claim 1 , wherein the one or more first spacers are floating in the membrane-electrode gap.

10. The electrochemical cell of claim 1 , wherein the one or more first spacers are a woven material, a knitted material, an expanded mesh, or an extruded mesh.

11. The electrochemical cell of claim 1 , wherein the one or more first spacers are made of polypropylene (PP), polyethylene (PE), high density polyethylene (HDPE), polyethylene teraphthalate, polyether ether ketone (PEEK), nylon, polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), polychlorotrifluoroethylene, ethylene chlorotrifluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), ethylene propylene, ethylene propylenediene, neoprene, or urethane.

12. The electrochemical cell of claim 1 , wherein the first direction is transverse to the second direction.

13. A method comprising:

positioning a first electrode inside an electrochemical cell;

positioning a membrane adjacent to the first electrode;

separating the first electrode from the membrane by a first membrane-electrode gap; and

positioning one or more first spacers in the first membrane-electrode gap between the first electrode and the membrane, wherein the one or more first spacers comprise one or more first features extending in a first direction and one or more second features extending in a second direction, wherein the first direction is different from the second direction, and wherein a thickness of at least a portion of the one or more first features is greater than a corresponding thickness of at least a corresponding portion of the one or more second features to form one or more pathways for flow of electrolyte or gas or both through the one or more spacers.

14. The method of claim 13 , wherein the first membrane-electrode gap is from about 0.2 mm to about 2 mm.

15. The method of claim 13 , further comprising positioning a second electrode adjacent to an opposite side of the membrane from the first electrode.

16. The method of claim 15 , further comprising operating the electrochemical cell at a specified cell current density to produce hydrogen gas at the first electrode or at the second electrode.

17. The method of claim 15 , further comprising positioning one or more second spacers in a second membrane-electrode gap between the second electrode and the membrane.

18. The method of claim 17 , wherein positioning the one or more second spacers comprises placing the one or more second spacers in direct contact with the second electrode and the membrane.

19. The method of claim 13 , wherein positioning the one or more first spacers comprises placing the one or more first spacers in direct contact with the first electrode and the membrane.

20. The method of claim 13 , further comprising flowing an electrolyte through the pathways of the one or more spacers.

21. The method of claim 13 , wherein the first direction is transverse to the second direction.