Vapor diffusion type fuel cell electrode presents a nonwetting barrier to the liquid feedstocks so they may contact the electrolyte only in the vapor state. Thus, it effects feedstock mixing with the electrolyte at the electrolyte/catalyst interface but prevents feedstock decomposition and catalyst poisoning from liquid mingling

Smith, J. O.

English

NASA Technical Reports Server

PTS-13M 
June 1966	 Brief 66-10281 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Vapor Diffusion Electrode Improves Fuel Cell Operation 
Porous Barrier
	 Vent Port 
Catalytic Layer	 Electrolyte 
The problem: 
To design a fuel cell electrode that will effect mixing 
of the feedstock with the electrolyte at the electrolyte/ 
catalyst interface but prevent decomposition of the 
feedstock and poisoning of the catalyst by liquid 
mingling. 
The solution: 
A vapor diffusion type electrode that presents a 
nonwetting barrier to the liquid feedstocks so that they 
may contact the electrolyte only in the vapor state. 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
How it's done: 
Control of feedstock flow is identical for both fuel 
and oxidant; however, only the fuel is discussed here. 
The fuel contacts the nonwetting porous barrier that 
prevents its passage in the liquid state but permits it to 
pass through as a vapor. As the fuel reaches the elec-
trolyte/catalyst interface, it mixes with and dissolves 
in the electrolyte, thus retaining the desirable effect of 
simultaneous triple contact of catalytic electrode, fuel, 
and electrolyte. At the outside face of the porous bar-
rier, the bulk of the fuel remains in the liquid state, an 
(continued overleat) 
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000280 2020-03-11T17:38:18+00:00Z
advantage in handling as compared to gaseous fuel 
requirements of heavy pressure containers. 
Notes: 
1. Highly fluorinated polymers with approximately 
10 to 15 micron pores have been found satisfactory 
for use with standard feedstocks and electrolyte. 
2. For rapid transmission of feedstock to the catalytic 
electrode surface, barrier thickness should be as 
small as is consistent with retention of its non-
wetting ability.
Patent status: 
Title to this invention has been waived under the 
provisions of the National Aeronautics and Space Act 
(42 U.S.C. 2457 (f)) to the Monsanto Research Cor-
poration, 800 North Lindbergh Boulevard, St. Louis, 
Missouri 63166.
Source: John 0. Smith
of Monsanto Research Corporation 
under contract to

Lewis Research Center
(Lewis-l87) 
Brief 66-10281	 Category 03


Vapor diffusion electrode improves fuel cell operation

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