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Title: Charging/discharging stability of a metal hydride battery electrode

Abstract

The metal hydride (MH) alloy powder for the negative electrode of the Ni/MH battery was first pulverized and oxidized by electrochemically charging and discharging for a number of cycles. The plate of the negative electrode of an experimental cell in this study was made from a mixture of a multicomponent AB{sub 5}-based alloy powder, nickel powder, and polytetra fluoroethylene (PTFE). The characteristics of the negative electrode, including discharge capacity, exchange current density, and hydrogen diffusivity, were studied by means of the electrochemical experiments and analysis in an experimental cell. The exchange current density of a Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85}Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35} alloy electrode increases with increasing number of charge/discharge cycles and then remains almost constant after 20 cycles. A microcracking activation, resulting from an increase in reaction surface area and an improvement in the electrode surface activation, increases the hydrogen exchange current densities. Measurement of hydrogen diffusivities for Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85}Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35} alloy powder shows that the ratio of D/a{sup 2} (D = hydrogen diffusivity; a = sphere radius) increases with increasing number of cycles but remains constant after 20 cycles.

Authors:
; ;  [1];  [2]
  1. Univ. of Windsor, Ontario (Canada). Dept. of Mechanical and Materials Engineering
  2. Ryerson Polytechnic Univ., Toronto, Ontario (Canada). Faculty of Engineering and Applied Science
Publication Date:
OSTI Identifier:
680035
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 146; Journal Issue: 7; Other Information: PBD: Jul 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE; NICKEL-HYDROGEN BATTERIES; BATTERY CHARGING; VOLTAGE DROP; STABILITY; ANODES; MISCH METAL; TITANIUM ALLOYS; NICKEL ALLOYS; COBALT ALLOYS; MANGANESE ALLOYS; ALUMINIUM ALLOYS; ELECTRICAL PROPERTIES

Citation Formats

Geng, M., Han, J., Feng, F., and Northwood, D.O. Charging/discharging stability of a metal hydride battery electrode. United States: N. p., 1999. Web. doi:10.1149/1.1391943.
Geng, M., Han, J., Feng, F., & Northwood, D.O. Charging/discharging stability of a metal hydride battery electrode. United States. doi:10.1149/1.1391943.
Geng, M., Han, J., Feng, F., and Northwood, D.O. Thu . "Charging/discharging stability of a metal hydride battery electrode". United States. doi:10.1149/1.1391943.
@article{osti_680035,
title = {Charging/discharging stability of a metal hydride battery electrode},
author = {Geng, M. and Han, J. and Feng, F. and Northwood, D.O.},
abstractNote = {The metal hydride (MH) alloy powder for the negative electrode of the Ni/MH battery was first pulverized and oxidized by electrochemically charging and discharging for a number of cycles. The plate of the negative electrode of an experimental cell in this study was made from a mixture of a multicomponent AB{sub 5}-based alloy powder, nickel powder, and polytetra fluoroethylene (PTFE). The characteristics of the negative electrode, including discharge capacity, exchange current density, and hydrogen diffusivity, were studied by means of the electrochemical experiments and analysis in an experimental cell. The exchange current density of a Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85}Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35} alloy electrode increases with increasing number of charge/discharge cycles and then remains almost constant after 20 cycles. A microcracking activation, resulting from an increase in reaction surface area and an improvement in the electrode surface activation, increases the hydrogen exchange current densities. Measurement of hydrogen diffusivities for Mm{sub 0.95}Ti{sub 0.05}Ni{sub 3.85}Co{sub 0.45}Mn{sub 0.35}Al{sub 0.35} alloy powder shows that the ratio of D/a{sup 2} (D = hydrogen diffusivity; a = sphere radius) increases with increasing number of cycles but remains constant after 20 cycles.},
doi = {10.1149/1.1391943},
journal = {Journal of the Electrochemical Society},
number = 7,
volume = 146,
place = {United States},
year = {1999},
month = {7}
}