Patent US5992008A successfully refreshed from Google Patents.
US5992008A
Expired / Lapsed
US
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Direct methanol feed fuel cell with reduced catalyst loading
Assignee: California Institute of Technology
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Filing: 1998-02-10
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Granted: 1999-11-30
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Expires: 2018-02-10
Abstract
Abstract Improvements to direct feed methanol fuel cells include new protocols for component formation. Catalyst-water repellent material is applied in formation of electrodes and sintered before application of ionomer. A membrane used in formation of an electrode assembly is specially pre-treated to improve bonding between catalyst and membrane. The improved electrode and the pre-treated membrane are assembled into a membrane electrode assembly.
Inventors
- 👤 Andrew Kindler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:51
CPC Classifications
H; H01; H01M; H01M8/00; H01M8/10; H01M8/1004; H01M2300/00; H01M2300/0017; H01M2300/0065; H01M2300/0082; H01M2300/0085; H01M8/1009; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50; Y10; Y10T; Y10T29/00; Y10T29/53; Y10T29/5313; Y10T29/53135; Y10T29/532; Y10T29/53204
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
125 words
A method of forming a fuel cell, comprising: obtaining catalyst material of a type that catalyzes an electrochemical reaction; mixing said catalyst material with a material that has a tendency to repel water to form a catalyst ink; applying said catalyst ink to an electrode backing material to form a catalyst-coated electrode; sintering said catalyst-coated electrode; cooling said catalyst-coated electrode after said sintering; applying an ionomer to said catalyst-coated electrode after said cooling, to form an electrochemical anode element or a electrochemical cathode element; pre-treating a solid electrolyte membrane in order to soften and swell said membrane; and hot press bonding said solid electrolyte membrane, which has been softened and swelled, between said anode element and said cathode element to form a membrane electrode assembly.
Claim 2
Independent Claim
125 words
A method of forming a fuel cell, comprising: obtaining catalyst material of a type that catalyzes an electrochemical reaction; mixing said catalyst material with a material that has a tendency to repel water to form a catalyst ink; applying said catalyst ink to an electrode backing material to form a catalyst-coated electrode; sintering said catalyst-coated electrode; cooling said catalyst-coated electrode after said sintering; applying an ionomer to said catalyst-coated electrode after said cooling, to form an electrochemical anode element or a electrochemical cathode element; pre-treating a solid electrolyte membrane in order to soften and swell said membrane; and hot press bonding said solid electrolyte membrane, which has been softened and swelled, between said anode element and said cathode element to form a membrane electrode assembly.
Claim 3
Dependent Claim
24 words
A method as recited in claim 1, wherein said catalyst material is of a type that catalyzes anode reactions when forming said anode element.
Claim 4
Dependent Claim
15 words
A method as recited in claim 2, wherein said catalyst material is a platinum-ruthenium catalyst.
Claim 5
Dependent Claim
24 words
A method as recited in claim 1, wherein said catalyst material is of a type that catalyzes cathode reactions when forming said cathode element.
Claim 6
Dependent Claim
15 words
A method as recited in claim 4, wherein said catalyst material is a platinum catalyst.
Claim 7
Dependent Claim
14 words
A method as recited in claim 1, wherein said water-repelling material is polytetrafluoroethylene (PTFE).
Claim 8
Dependent Claim
27 words
A method as recited in claim 1, wherein said catalyst ink consists of an agent which ensures proper dispersion of said catalyst material within said catalyst ink.
Claim 9
Dependent Claim
19 words
A method as recited in claim 7, wherein said agent is a solution of water mixed with triton detergent.
Claim 10
Dependent Claim
19 words
A method as recited in claim 1, wherein said electrode backing material is a porous carbon fiber backing sheet.
Claim 11
Dependent Claim
17 words
A method as recited in claim 1, wherein said sintering occurs at temperatures above 300 degrees Celsius.
Claim 12
Dependent Claim
14 words
A method as recited in claim 1, wherein said sintering occurs under nitrogen gas.
Claim 13
Dependent Claim
25 words
A method as recited in claim 1, wherein said cooling is applied until said catalyst-coated electrode is cooled to room temperature, approximately 25 degrees Celsius.
Claim 14
Dependent Claim
19 words
A method as recited in claim 1, wherein said ionomer is liquid co-polymer of tetrafluroethylene and perfluorovinylether sulfonic acid.
Claim 15
Dependent Claim
17 words
A method as recited in claim 1, wherein said solid electrolyte membrane is a perfluorinated proton-exchange membrane.
Claim 16
Dependent Claim
18 words
A method as recited in claim 1, wherein said pre-treating is achieved with a softening and swelling agent.
Claim 17
Dependent Claim
17 words
A method as recited in claim 15, wherein said softening and swelling agent is an isopropanol solution.
Claim 18
Dependent Claim
17 words
A method as recited in claim 16, wherein said isopropanol solution has a concentration of 5.3 moles/liter.
Claim 19
Independent Claim
79 words
A method of forming an electrode for a fuel cell, comprising: obtaining catalyst material of a type that catalyzes an electrochemical reaction; mixing said catalyst material with a material that has a tendency to repel water to form a catalyst ink; applying said catalyst ink to an electrode backing material to form a catalyst-coated electrode; sintering said catalyst-coated electrode; cooling said catalyst-coated electrode after said sintering; obtaining an ionomer; applying said ionomer to said catalyst-coated electrode after said cooling.
Claim 20
Independent Claim
79 words
A method of forming an electrode for a fuel cell, comprising: obtaining catalyst material of a type that catalyzes an electrochemical reaction; mixing said catalyst material with a material that has a tendency to repel water to form a catalyst ink; applying said catalyst ink to an electrode backing material to form a catalyst-coated electrode; sintering said catalyst-coated electrode; cooling said catalyst-coated electrode after said sintering; obtaining an ionomer; applying said ionomer to said catalyst-coated electrode after said cooling.
Claim 21
Dependent Claim
14 words
A method as recited in claim 18, wherein said water-repelling material is polytetrafluoroethylene (PTFE).
Claim 22
Dependent Claim
27 words
A method as recited in claim 18, wherein said catalyst ink consists of an agent which ensures proper dispersion of said catalyst material within said catalyst ink.
Claim 23
Dependent Claim
19 words
A method as recited in claim 20, wherein said agent is a solution of water mixed with triton detergent.
Claim 24
Dependent Claim
19 words
A method as recited in claim 18, wherein said electrode backing material is a porous carbon fiber backing sheet.
Claim 25
Dependent Claim
17 words
A method as recited in claim 18, wherein said sintering occurs at temperatures above 300 degrees Celsius.
Claim 26
Dependent Claim
14 words
A method as recited in claim 18, wherein said sintering occurs under nitrogen gas.
Claim 27
Dependent Claim
25 words
A method as recited in claim 18, wherein said cooling is applied until said catalyst-coated electrode is cooled to room temperature, approximately 25 degrees Celsius.
Claim 28
Dependent Claim
19 words
A method as recited in claim 18, wherein said ionomer is liquid co-polymer of tetrafluroethylene and perfluorovinylether sulfonic acid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-11-29 | 2003-05-31 | 2003-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-11-29 | 2007-05-31 | 2007-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-11-29 | 2011-05-31 | 2011-11-30 | $7700.00 | Window Closed / Lapsed |