Procedure for enhancing operating life and performance of oxygen electrodes in rechargeable metal-oxygen batteries and hydrogen-oxygen fuel cells is discussed. Accumulation of refractory anodic oxide layer and inhibiting effects on oxygen reduction are described. Improvements in service life of batteries by following procedure are explained

Holleck, G. L.

Malachesky, P. A.

English

NASA Technical Reports Server

August 1972	 B72-10479 
NASA TECH BRIEF 
Lewis Research Center 	 A £ 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
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Improved Operation of Rechargeable Oxygen Electrodes 
No. 3 
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Time (Minutes)
Effect Of Temporary Short-Circuiting On H 2 /02 Fuel Cells 
The operating life and performance of oxygen elec-
trodes in rechargeable metal-oxygen batteries and hydro-
gen-oxygen fuel cells can be enhanced by incorporating 
a brief, high-rate discharge pulse in the operating cycle. 
The pulse rejuvenates oxygen electrode activity by 
removing a refractory anodic oxygen layer which builds 
up on the electrodes with repeated cycling. 
During an investigation to establish the failure modes 
of Teflon-bonded platinum black rechargeable oxygen 
electrodes used in metal-oxygen batteries and hydrogen-
oxygen fuel cells, it was found that extended cycling led 
to accumulation of a refractory anodic oxygen layer
which apparently inhibited oxygen reduction. It has 
been shown that this inhibiting layer can be removed by 
cathodic reduction, thereby restoring oxygen electrode 
activity. Tests made on laboratory hydrogen-oxygen fuel 
cells operating in the rechargeable mode have shown 
that temporary short-circuiting for periods ranging from 
three minutes to one second or less restored cell voltages 
as shown in the figure. 
This technology is believed to be readily applicable to 
operational metal-oxygen batteries and hydrogen-oxygen 
fuel cells. It is further believed that complete short-
circuiting may not be necessary and that oxygen elec-
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
(continuous overleaf) 
Government assumes any liability resulting from the use of the 
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trode rejuvenation may be accomplished by a brief, 
high-rate discharge; however, this has not been explored. 
Notes: 
1. Although this technology appears to be specific to 
rechargeable oxygen. electrodes, rejuvenation of other 
fuel cell electrodes by pulsing seems possible as a 
means of increasing life and performance. 
2. No detailed technical documentqtion is available. 
Specific questions, however, may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B72-10479 
3. A report of the research project during which this 
technology was established may be obtained from:
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: NASA CR-72999 (N72-10051), 
Research on Rechargeable Oxygen Electrodes 
Patent status: 
No patent action is contemplated by NASA. 
Source: Paul A. Malachesky and
Gerhard L. Holleck of 
Tyco Corporate Technology Center 
under contract to
Lewis Research Center 
(LEW- 11619) 
B72-10479	 Category 01, 04


Improved operation of rechargeable oxygen electrodes

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