Nickel Hydrogen Cell Positive-Electrode Studies: Cobalt Segregation in Reducing Environments,

Abstract

Nickel electrodes from nickel hydrogen battery cells that had exhibited anomalously low capacities have been tested. Electrode characterization tests showed that changes had occurred in the electrode active material to increase the charge and discharge voltages. The increased charge voltages resulted in a decrease in charge efficiency. These changes apparently resulted from storage of the cell at low voltage with excess hydrogen present in the cell. Chemical and physical analyses indicated that cobalt, a 10% additive in the nickel electrode active material, had undergone segregation from the active material to form a cobalt rich compound that is not normally present in the electrodes. This chemical change is felt to be largely responsible for the changes in electrode performance. A model for the processes causing cobalt segregation is described, and test results are presented to support the model. Keywords: Batteries, Fuel cells, High energy density, Spacecraft power requirements.

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Document Details

Document Type
Technical Report
Publication Date
May 22, 1987
Accession Number
ADA193025

Entities

People

  • Albert H. Zimmerman

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Advanced Electronics
  • Space

DTIC Thesaurus Topics

  • Cells
  • Chemical Analysis
  • Classification
  • Diffraction
  • Efficiency
  • Electrochemical Reactions
  • Electrodes
  • Elements
  • Hydrogen
  • Low Earth Orbits
  • Low Voltage
  • Materials
  • Nitric Acid
  • Resistance
  • Security
  • Voltage
  • X-Ray Diffraction

Readers

  • Electrochemical Engineering/ Fuel Cell Technologies
  • Theoretical Analysis.
  • Thin Film Deposition Science.

Technology Areas

  • Biotechnology
  • Space
  • Space - Hall-Effect Thruster