Proton-exchange membrane

1. A proton-exchange membrane comprising:

a polymer matrix, polymer fibers, or a combination thereof; and

a proton-conducting material distributed in the polymer matrix, on the polymer fibers, in the polymer fibers, or a combination thereof, wherein the proton-conducting material comprises an alkali thio-hydroxo metal, an alkali thio-hydroxo metalloid, a pyrophosphate, an ultraphosphate, or a combination thereof.

2. The membrane of claim 1 , wherein the membrane comprises particles of the proton-conducting material.

3. The membrane of claim 1 , wherein the membrane comprises the polymer fibers with the proton-conducting material distributed on the polymer fibers, in the polymer fibers, or a combination thereof.

4. The membrane of claim 1 , wherein the membrane comprises the polymer matrix with the proton-conducting material distributed in the polymer matrix.

5. The membrane of claim 4 , wherein the proton-conducting material comprises proton-conducting nanofibers.

6. The membrane of claim 1 , wherein the proton-conducting material comprises cesium thio-hydroxogermanate (CTHG), cerium ultraphosphate, cesium ultraphosphate, or a combination thereof.

7. The membrane of claim 1 , comprising:

the polymer matrix comprising polybenzimidazole (PBI); and

proton-conducting nanofibers distributed in the polymer matrix, each nanofiber comprising

a core that is continuous along a length of the nanofiber and that comprises the proton-conducting material, and

a shell that is continuous along the length of the nanofiber, the shell comprising polybenzimidazole (PBI).

8. The membrane of claim 1 , comprising:

the polymer matrix comprising polybenzimidazole (PBI); and

particles comprising the proton-conducting material homogeneously distributed in the polymer matrix.

9. The membrane of claim 1 , comprising:

the polymer fibers comprising polybenzimidazole (PBI); and

the proton-conducting material distributed on the polymer fibers, in the polymer fibers, or a combination thereof;

wherein the polymer fibers having the proton-conducting material thereon are matted together in an orientation that is substantially parallel to a plane of the membrane.

10. An ammonia-forming apparatus or a water-electrolysis apparatus comprising the membrane of claim 1 .

11. An electrochemical cell comprising:

an anode;

a cathode; and

a membrane separating the anode and the cathode, the membrane comprising the membrane of claim 1 .

12. A method of using the membrane of claim 1 , the method comprising:

conducting protons from one major face of the membrane to another major face with a conductivity of 10 −6 S/cm to about 10 −1 S/cm while the membrane is at a temperature of ≥200 to ≤450° C.

13. A method of making the membrane of claim 1 , the method comprising:

combining a polymer solution and a suspension of particles comprising the proton-conducting material to form a mixture;

applying the mixture to a flat surface; and

drying the mixture on the flat surface to form the membrane.

14. A method of water electrolysis or of forming ammonia using the membrane of claim 1 , the method comprising:

generating hydrogen from a cathode of an electrolysis cell, or generating ammonia from a cathode of an ammonia-production cell, the electrolysis cell or ammonia-production cell comprising

an anode,

the cathode, and

a membrane separating the anode and the cathode, the membrane comprising the membrane of claim 1 .

15. A method of operating an electrochemical cell comprising the membrane of claim 1 , the method comprising:

generating an electrical potential between an anode and a cathode of the electrochemical cell, the electrochemical cell comprising

the anode,

the cathode, and

a membrane separating the anode and the cathode, the membrane comprising the membrane of claim 1 .

16. A method of making a proton-exchange membrane, the method comprising:

forming core-shell nanofibers comprising a core and shell, the forming comprising electrospinning a polymer to form the core comprising a polymer and electrospray coating the core or solution dipping the core to form the shell comprising a proton-conducting material, or the forming comprising co-electrospinning a solution comprising the proton-conducting material and a solution comprising the polymer to form the core that comprises the proton-conducting material and the shell that comprises a polymer; and

heat pressing the nanofibers to form the membrane, wherein the membrane comprises

the nanofibers; and

the proton-conducting material distributed on the nanofibers, in the nanofibers, or a combination thereof.

17. A method of making a proton-exchange membrane, the method comprising:

combining a polymer solution and particles comprising a proton-conducting material to form a mixture;

drying the mixture;

pulverizing the dried mixture;

optionally further processing the dried mixture comprising adding a polymer solution to the dried mixture, drying the resulting mixture, and pulverizing the resulting dried mixture;

adding a solvent to the dried mixture to form a dough; and

pressing the dough to form the membrane, wherein the membrane comprises

a polymer matrix, polymer fibers, or a combination thereof, and

the proton-conducting material distributed in the polymer matrix, on the polymer fibers, in the polymer fibers, or a combination thereof.

18. A method of making a proton-exchange membrane, the method comprising:

combining a polymer solution and a suspension of particles comprising a proton-conducting material to form a mixture;

electrospinning the mixture to form polymer fibers comprising particles therein, the particles comprising the proton-conducting material; and

heat pressing the polymer fibers into a mat, to form the membrane, wherein the membrane comprises

the polymer fibers; and

a proton-conducting material distributed on the polymer fibers, in the polymer fibers, or a combination thereof.