Fuel cell regenerated by photochemical reduction enables novel slurry system to transport particles of reduced silver between regenerator section and anode. Fundamental reactions which provide electrical power from the fuel cell are given

Lieberman, M.

English

NASA Technical Reports Server

1972	 B72-10221 
NASA TECH BRIEF 
Ames Research Center 	 A A 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Silver-Chlorine Fuel Cell - A Concept 
The problem: 
To construct a silver-chlorine fuel cell which is 
regenerated by photochemical reduction; one of the 
complications is that silver particles must be effective-
ly circulated and made available for reaction. 
hU 
The solution: 
A novel slurry system which enables transport of 
particles of reduced silver between the regenerator 
section and the anode. 
How it's done: 
The fundamental reaction which provides electrical 
power from the type of fuel cell shown in the diagram 
1s:
2 Ag +C12= 2  AgCI.
The central compartment of the fuel cell contains 
a slurry of silver chloride (A gCI) and silver particles, 
and chloride ion as provided by a suitable electrolyte. 
The main stream of the pump which handles this 
slurry is directed toward the porous carbon anode 
collector; additionally, the pump also evacuates the 
anode chamber. As a result, the slurry handled by the 
pump is caused to pass through the porous carbon 
anode collector. Silver particles in the slurry come 
into contact with the carbon anode structure and the 
following reaction • takes place when power is with-
drawn from the cell: 
Ag + Cl— = AgCl + 
The silver chloride that is formed in the anode 
structure is a solid, but it is removed and carried 
along in the main stream of slurry. In due course, the 
silver chloride enters the regenerator where it is re-
duced by light (as in photographic processes): 
2 Ag Cl = 2 Ag + C12. 
The slurry stream flowing out of the regenerator 
now contains bubbles of chlorine gas as well as par-
ticles of silver and unreduced silver chloride; the 
chlorine gas is removed by a senarator and conducted 
to the cathode compartment. The chlorine gas perme-
ates the porous carbon cathode structure and when 
power is withdrawn from the cell, the following re-
action takes place: 
C12+ 2e = 2 Cl—. 
The handlingof slurries in fuel cells has been 
studied in detail in more complex systems involving 
hydrogen, oxygen, and solid catalysts. The mechanical 
details of systems for circulating slurries are fairly 
well established. 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
.
https://ntrs.nasa.gov/search.jsp?R=19720000221 2020-03-17T03:33:22+00:00Z
Notes: 
1. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $6.00 
(or microfiche $0.95) 
Reference: 
NASA CR-94407(N68-22889), Feasability 
Study of High Performance Hydrogen-
Oxygen Fuel Cells. 
2. Regeneration of silver chloride may also be effected 
by chemical means, for example, by the compounds 
ordinarily used as photographic developers or 
strong reducing agents such as hydrazine.
3. No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10221 
Patent status: 
No patent action is contemplated by NASA. 
Source: Martin Lieberman of

ESSO Research and Engineering Co.

under contract to

Ames Research Center

(ARC-10491) 
B72-10221	 Category 03


Silver-chlorine fuel cell: A concept

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server