Enhancing catalyst activity of a pem fuel cell electrode with an ionic liquid additive

Patent metadata

Field	Value
Publication number	US-2019267636-A1
Application number	US-201815906301-A
Country	US
Kind code	A1
Filing date	Feb 27, 2018
Priority date	Feb 27, 2018
Publication date	Aug 29, 2019
Grant date	—

Abstract

A method of forming a catalyst-containing electrode layer for a polymer electrolyte membrane (PEM) fuel involves permeating an electrode layer with a liquid additive composition that comprises an ionic liquid additive and a carrier solvent. The electrode layer is then dried to remove the carrier solvent and deposit the ionic liquid additive within the electrode layer. The ionic liquid additive may be an organic cation of an ionic liquid, an organic anion of an ionic liquid, or both an organic cation and an organic anion of an ionic liquid. Once the electrode layer with its internal loading of the ionic liquid additive has been formed, a polymer electrolyte membrane fuel cell may be assembled such that the electrode layer constitutes either an anode layer or a cathode layer of the PEM fuel cell.

First claim

What is claimed is:

1 . A method of forming a catalyst-containing electrode layer for a polymer electrolyte membrane fuel cell, the method comprising:
(a) applying a layer of an electrode ink composition onto a surface of a substrate, the electrode ink composition comprising an ionomer and a catalyst dissolved or dispersed in a dispersion solvent; (b) drying the layer of the electrode ink composition to form an electrode layer having a thickness that ranges from 2 μm to 20 μm on the substrate; (c) permeating the electrode layer with a liquid additive composition that comprises an ionic liquid additive and a carrier solvent; and (d) drying the electrode layer after the electrode layer has been permeated with the liquid additive composition to remove the carrier solvent and deposit the ionic liquid additive within the electrode layer.

2 . The method set forth in claim 1 , further comprising:
assembling a polymer electrolyte membrane fuel cell that includes a proton-conductive solid polymer electrolyte membrane sandwiched between an anode layer configured to receive hydrogen gas and a cathode layer configured to receive oxygen gas, a first gas diffusion media layer overlying the anode layer, a second gas diffusion media layer overlying the cathode layer, a first electrically-conductive flow field plate overlying the first gas diffusion media, and a second electrically-conductive flow field plate overlying the second gas diffusion media, and wherein the electrode layer constitutes either the anode layer or the cathode layer.

3 . The method set forth in claim 2 , wherein the substrate is the proton-conductive solid polymer electrolyte membrane.

4 . The method set forth in claim 2 , wherein the substrate is the first gas diffusion media layer or the second gas diffusion media layer.

5 . The method set forth in claim 2 , wherein the substrate is a decal substrate, and wherein assembling the polymer electrolyte fuel cell further comprises:
transferring the electrode layer from the decal substrate onto a face of the proton-conductive solid polymer electrolyte membrane.

6 . The method set forth in claim 1 , wherein the ionic liquid additive includes an organic cation of an ionic liquid.

7 . The method set forth in claim 6 , wherein the organic cation of an ionic liquid includes at least one of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene; 1-butyl-1-methylpiperidinium; or 1,1,3,3-tetramethylguanidine.

8 . The method set forth in claim 1 , wherein the ionic liquid additive includes an organic anion of an ionic liquid.

9 . The method set forth in claim 8 , wherein the organic anion of an ionic liquid includes bis(perfluoroethylsulfonyl)imide.

10 . The method set forth in claim 1 , wherein the ionic liquid additive includes both an organic cation of an ionic liquid and an organic anion of an ionic liquid.

11 . The method set forth in claim 10 , wherein the organic cation of an ionic liquid includes at least one of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene; 1-butyl-1-methylpiperidinium; or 1,1,3,3-tetramethylguanidine, and wherein the organic anion of an ionic liquid includes bis(perfluoroethylsulfonyl)imide.

12 . The method set forth in claim 1 , further comprising:
(e) repeating steps (c) and (d) at least once to deposit additional ionic liquid additive within the electrode layer.

13 . The method set forth in claim 12 , wherein steps (c) and (d) are performed to deposit within the electrode layer one of an organic cation of an ionic liquid or an organic anion of an ionic liquid, and wherein step (e) is performed to deposit within the electrode layer the other of an organic cation of an ionic liquid or the organic anion of an ionic liquid.

14 . The method set forth in claim 1 , wherein the catalyst comprises catalyst nanoparticles supported on carbon support structures, and wherein the electrode layer has an ionic liquid additive internal loading, as expressed in a weight ratio of the ionic liquid additive to carbon of the carbon support structures of the catalyst, that ranges from 0.03 to 0.50.

15 . A method of forming a catalyst-containing electrode layer for a polymer electrolyte membrane fuel cell, the method comprising:
(a) providing an electrode layer that is supported on a substrate and includes a catalyst dispersed in an ionomer binder, the catalyst comprising catalyst nanoparticles supported on carbon support structures; (b) permeating the electrode layer with a liquid additive composition that comprises an ionic liquid additive and a carrier solvent, the ionic liquid additive being an organic cation of an ionic liquid, an organic anion of an ionic liquid, or both an organic cation and an organic anion of an ionic liquid; and (c) drying the electrode layer after the electrode layer has been permeated with the liquid additive composition to remove the carrier solvent and deposit the ionic liquid additive within the electrode layer; and (d) assembling a polymer electrolyte membrane fuel cell that includes a proton-conductive solid polymer electrolyte membrane sandwiched between the electrode layer disposed on one face of the polymer electrolyte membrane as a cathode layer and another electrode layer disposed on an opposite face of the polymer electrolyte membrane as an anode layer, and wherein the electrode layer that includes the ionic additive has an ionic liquid additive internal loading, as expressed in a weight ratio of the ionic liquid additive to carbon of the carbon support structures of the catalyst, that ranges from 0.03 to 0.50.

16 . The method set forth in claim 15 , wherein providing the electrode layer comprises:
(a1) applying a layer of an electrode ink composition onto a surface of a substrate, the electrode ink composition comprising an ionomer and a catalyst dissolved or dispersed in a dispersion solvent; and (a2) drying the layer of the electrode ink composition to form the electrode layer on the substrate;

17 . The method set forth in claim 15 , wherein steps (b) and (c) are repeated at least once to deposit additional ionic liquid additive within the electrode layer.

18 . The method set forth in claim 15 , wherein steps (b) and (c) are performed to deposit within the electrode layer one of an organic cation of an ionic liquid or an organic anion of an ionic liquid, and wherein steps (b) and (c) are repeated at least once to deposit within the electrode layer the other of the organic cation of an ionic liquid or the organic anion of an ionic liquid.

19 . The method set forth in claim 15 , wherein the ionic liquid additive includes an organic cation of an ionic liquid or an organic anion of an ionic liquid.

20 . The method set forth in claim 15 , wherein the ionic liquid additive includes an organic cation of an ionic liquid and an organic anion of an ionic liquid, wherein the organic cation of an ionic liquid includes at least one of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene; 1-butyl-1-methylpiperidinium; or 1,1,3,3-tetramethylguanidine, and wherein the organic anion of an ionic liquid includes bis(perfluoroethylsulfonyl)imide.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Kongkanand Anusorn
• Yarlagadda Venkata

Classifications

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• H01M8/1018

  Polymeric electrolyte materials · CPC title

• H01M4/8828 Primary

  Coating with slurry or ink · CPC title

• H01M4/8878

  Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body · CPC title

• H01M4/8882

  Heat treatment, e.g. drying, baking · CPC title