Zinc-oxygen primary cell yields high energy density for battery used as an auxiliary power source in space vehicle systems. Maximum reliability and minimum battery weight is achieved by using a stacking configuration of 23 series-connected modules with 6 parallel-connected cells per module

Graff, C. B.

English

NASA Technical Reports Server

June 1968	 Brief 68-10218 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Zinc—Oxygen Primary Cell Yields High Energy Density 
Anode Terminal 
Anode Cover Seal 
Cathode 
Terminal 
Electrode 
Separator. I Tf-. 
02 Cavity	 :• KOH Electrolyte 
Zinc Anode 
A zinc-oxygen primary cell has been developed to 
meet requirements for a reliable high-energy density 
battery for service as an auxiliary power source in 
space vehicle systems. The cell yields energy densities 
considerably in excess of conventional primary cells. 
For example, in a discharge time of 8 hours this cell 
yields an energy density of 120 watt-hours per pound 
of cell weight compared to 75 watt-hours per pound 
for a silver-zinc alkaline cell. 
The zinc-oxygen cell (of square bi-cell construction 
to maximize zinc area per unit weight) incorporates 
two cathodes consisting of stable, efficient semi-
permeable films. These film cathodes permit oxygen 
to pass through to the catalyst side to be reduced, yet 
retain the alkaline electrolyte (KOH) within the cell. 
The two cathodes, connected in parallel, are supported 
by a frame. The anode, made of porous zinc, is 
wrapped in separator material and inserted into the 
frame between the two cathodes. Intimate contact
between the anode, separator, and cathode is achieved 
by proper cell support and stacking. The electrolyte, 
which provides a continuous ionic path, is used in an 
amount just sufficient to saturate the anode struc-
ture and separator material. 
The oxidation-reduction reactions that occur in the 
cell during electrical power withdrawal may be repre-
sented as follows:
2—
Anode: Zn +40H - Zn0 + 21420 + 2e 
Cathode: 1/2 02 + H20 + 2e- - 20H 
Cell: Zn+ 1/202-ZnO 
The zinc is oxidized at the anode, as electrons are 
released to the external circuit. These electrons pass 
through the external circuit to the cathode where they 
take part in the reduction of oxygen to hydroxyl ions. 
The net cell reaction results in oxidation of zinc and 
reduction of oxygen to form zinc oxide. Overall cell 
potential is 1.617 volts.
(continued overleaf) 
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
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=19680000218 2020-03-12T05:34:31+00:00Z
Analytical studies were made to establish the opti-
mum number of cells and stacking configurations in 
batteries required to yield tile maximum energy den-
sity and overall system reliability. The results of these 
studies show that maximum energy densities occur 
when the batteries are designed to operate at current 
densities of 30 mA/cm 2. Maximum reliability and 
minimum battery weight would be achieved using a 
stacking configuration of 23 series-connected modules 
with 6 parallel-connected cells per module. A total of 
138 series/parallel-connected cells will be required for 
a 28-volt, 400 A-hr battery system.
Note: 
Inquiries concerning these cells may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10218 
Patent status: 
No patent action is contemplated by NASA. 
Source: Stewart Chodash 
of Leesona Moos Laboratory 
under contract to 
Marshall Space Flight Center 
and C. B. Graff 
of Marshall Space Flight Center 
(MFS- 14661) 
Brief 68-10218	 Category 01


Zinc-oxygen primary cell yields high energy density

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