Silicon phosphate and membrane comprising the same

Patent metadata

Field	Value
Publication number	US-10322942-B2
Application number	US-201013514577-A
Country	US
Kind code	B2
Filing date	Nov 29, 2010
Priority date	Dec 8, 2009
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

The invention provides a composition having the formula (I): xXO2.yY2O5, (wherein: 0.5<x<0.7; 0.3<y<0.5; X comprises one or more of silicon, titanium, germanium and zirconium; and Y comprises one or more of phosphorus, vanadium arsenic and antimony), or a hydrate thereof, in which the composition comprises more than 50 wt % or more of crystalline material.

First claim

The invention claimed is:

1. A proton-conducting membrane comprising a composition having the formula (I):
x XO 2 .y Y 2 O 5   (I),

or a hydrate thereof, wherein:
0.5<x<0.7;
0.3<y<0.5;
X is silicon and optionally at least one or more atoms selected from the group consisting of titanium, germanium and zirconium; and
Y is phosphorus and optionally at least one or more atoms selected from the group consisting of vanadium, arsenic and antimony;
in which the composition comprises 50 wt % or more of crystalline material and the membrane has a thickness of from 1 micron to 500 microns;
wherein the membrane is proton-conducting.

2. The membrane of claim 1 , wherein the composition is a hydrate of formula (Ia):
x XO 2 .y Y 2 O 5 .wy H 2 O  (Ia)

wherein x, X, y and Y are as defined in claim 1 ;
and 0<w<3.

3. The membrane of claim 1 , wherein X is silicon.

4. The membrane of claim 1 , wherein Y is phosphorus.

5. The membrane of claim 1 , wherein the composition is a phosphorus silicon oxide.

6. The membrane of claim 1 , wherein the composition is a nanocrystalline, proton conductor based upon a Si 5 P 6 O 25 structure.

7. The membrane of claim 6 , wherein the composition is a solid solution of silicon phosphorus oxide.

8. The membrane of claim 1 , wherein the composition is in a form selected from the group consisting of nanoparticles, a nanostructured material, a thin film, an amorphous phase and a ceramic.

9. The membrane of claim 1 , comprising a material comprising the composition, wherein the composition is chemically doped with one or more elements selected from the group consisting of boron, sulfur, arsenic, aluminium, titanium, antimony, tin, germanium and indium.

10. The membrane of claim 9 , wherein the material comprises SiP 2 O 7 in intimate mixture with the composition of formula (I).

11. The membrane of claim 9 , wherein the material further comprises a polymer not having proton-conducting properties.

12. The membrane of claim 11 , wherein the polymer not having proton-conducting properties is non-polar.

13. The membrane of claim 11 , wherein the polymer not having proton-conducting properties is selected from the group consisting of a poly(alkylene), PVC, PVB, PTFE and PVDF.

14. The membrane of claim 11 , wherein the polymer not having proton-conducting properties is porous, and the material comprises the composition in the pores of the porous polymer.

15. The membrane of claim 1 , which is a proton exchange membrane effective for use in a proton exchange membrane fuel cell.

16. A-fuel cell comprising the membrane of claim 1 .

17. A fuel cell stack comprising two or more fuel cells as defined in claim 16 .

18. An article powered by a fuel cell as defined in claim 16 or a fuel cell stack as defined in claim 17 .

19. A method of operating a fuel cell as defined in claim 16 or a fuel cell stack as defined in claim 17 comprising contacting the fuel cell with a reactant fuel and an oxidant to generate electricity, wherein the fuel cell is operated at a temperature of up to about 200° C. and/or a humidity of less than about 50%.

20. The membrane of claim 1 , having a thickness of from 10 microns to 250 microns.

21. The membrane of claim 20 , having a thickness of from 10 microns to 100 microns.

Assignees

• Attidekou Pierrot Sassou
• Irvine John Thomas Sirr
• Univ Court Univ St Andrews

Inventors

• Attidekou Pierrot Sassou
• Irvine John Thomas Sirr

Classifications

• C01G23/047 Primary

  Titanium dioxide · CPC title

• C01P2002/88

  by thermal analysis data, e.g. TGA, DTA, DSC · CPC title

• H01M8/0289

  Means for holding the electrolyte (solid polymer electrolytes H01M8/1018) · CPC title

• C08J2343/00

  Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing boron, silicon, phosphorus, selenium, tellurium or a metal; Derivatives of such polymers (of metal salts, e.g. phenolates, alcoholates, see the parent compounds) · CPC title

• C01P2004/03

  obtained by SEM · CPC title