Cyclic Voltametry Investigation of a Metal Hydride Electrode for Nickel Metal Hydride Batteries

Abstract

In this study, an -type hydrogen-absorbing alloy, was used as the negative electrode material. The metal-hydride (MH) electrode was charge/discharged over 200 cycles. The discharge capacity of the alloy was 250 mAh g−1. The specific discharge capacity as a function of discharge current density and temperature effect is also discussed. Hydrogen diffusion reaction in the MH alloy powder of the negative MH alloy electrode dominates the high-rate discharge capability of the metal hydride electrode in a nickel metal hydride (Ni/MH) battery. Cyclic voltametry technique was used to analyze the charge-transfer reactions at the electrode/electrolyte interface and hydrogen surface coverage capacity. The charge-transfer reaction in the negative electrode reflects a capability of hydrogen reduction and oxidation reactions at the electrode/electrolyte interface. © 2001 The Electrochemical Society. All rights reserved.