Durable fuel cell membrane electrode assembly with combined additives

Patent metadata

Field	Value
Publication number	US-9023496-B2
Application number	US-201213396093-A
Country	US
Kind code	B2
Filing date	Feb 14, 2012
Priority date	Dec 27, 2007
Publication date	May 5, 2015
Grant date	May 5, 2015

Abstract

A fuel cell membrane electrode assembly is provided comprising a polymer electrolyte membrane comprising a first polymer electrolyte and at least one manganese compound; and one or more electrode layers comprising a catalyst and at least one cerium compound. The membrane electrode assembly demonstrates an unexpected combination of durability and performance.

First claim

We claim:

1. A fuel cell membrane electrode assembly comprising:
a) a polymer electrolyte membrane comprising a first polymer electrolyte and at least one manganese cation, wherein the distribution of manganese cations across the thickness of the polymer electrolyte membrane is uniform, and wherein the distribution of manganese cations throughout the polymer electrolyte membrane is uniform; and
b) one or more electrode layers comprising a catalyst and at least one compound containing cerium and oxygen, wherein a total amount of compounds containing cerium and oxygen is between 0.01 and 5 percent by weight relative to the weight of catalyst present.

2. The fuel cell membrane electrode assembly according to claim 1 , wherein the first polymer electrolyte comprises bound anionic functional groups, wherein at least a portion of said anionic functional groups are in acid form and at least a portion of said anionic functional groups are neutralized by manganese cations.

3. The polymer electrolyte membrane according to claim 2 , wherein said manganese cations are Mn 2+ cations.

4. The fuel cell membrane electrode assembly according to claim 1 , wherein the first polymer electrolyte is highly fluorinated.

5. The fuel cell membrane electrode assembly according to claim 1 , wherein the first polymer electrolyte is perfluorinated.

6. The fuel cell membrane electrode assembly according to claim 1 , wherein the one or more electrode layers additionally comprise a second polymer electrolyte.

7. The fuel cell membrane electrode assembly according to claim 6 , wherein the second polymer electrolyte is highly fluorinated.

8. The fuel cell membrane electrode assembly according to claim 6 , wherein the second polymer electrolyte is perfluorinated.

9. The fuel cell membrane electrode assembly according to claim 2 , wherein the amount of manganese cations present is between 0.001 and 0.5 charge equivalents based on the molar amount of anionic functional groups present in the first polymer electrolyte.

10. The fuel cell membrane electrode assembly according to claim 2 , wherein the amount of manganese cations present is between 0.01 and 0.1 charge equivalents based on the molar amount of anionic functional groups present in the first polymer electrolyte.

11. The fuel cell membrane electrode assembly according to claim 1 , wherein said first polymer electrolyte has an equivalent weight of 900 or less.

12. The fuel cell membrane electrode assembly according to claim 1 , wherein said first polymer electrolyte comprises pendent groups according to the formula:
—O—CF 2 —CF 2 —CF 2 —CF 2 —SO 3 H.

13. The fuel cell membrane electrode assembly according to claim 1 , additionally comprising a porous support.

14. The fuel cell membrane electrode assembly according to claim 1 , wherein said cerium oxide compounds are CeO 2 .

15. The fuel cell membrane electrode assembly according to claim 1 , wherein said cerium oxide compounds are Ce 2 O 3 .

16. The fuel cell membrane electrode assembly according to claim 1 which contains at least 50% less manganese in the electrode layer(s) than in the polymer electrolyte membrane and at least 50% less cerium in the polymer electrolyte membrane than in the electrode layer(s).

17. The fuel cell membrane electrode assembly according to claim 1 , wherein a total amount of compounds containing cerium and oxygen is between 0.1 and 2 percent by weight relative to the weight of catalyst present.

18. The fuel cell membrane electrode assembly according to claim 1 , wherein a total amount of compounds containing cerium and oxygen is between 0.2 and 1.3 percent by weight relative to the weight of catalyst present.

Assignees

• Pierpont Daniel M
• Hamrock Steven J
• Frey Matthew H
• 3M Innovative Properties Co

Inventors

• Pierpont Daniel M
• Hamrock Steven J
• Frey Matthew H

Classifications

• H01M8/1025

  having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters · CPC title

• H01M2300/0082

  Organic polymers · CPC title

• H01M8/1004 Primary

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M8/1051 Primary

  Non-ion-conducting additives, e.g. stabilisers, SiO2 or ZrO2 · CPC title

• H01M2300/0091

  in the form of mixtures · CPC title