Hydrogen Gas-Rechargeable Metal Hydride Electrode for Ni-MH Battery (II)

Abstract

The present study is a follow-up of a previous work on hydrogen gas-rechargeable metal hydride (MH) electrode for Ni-MH battery. The hydrogen pressure drop in a battery during hydrogen absorption and electrochemical discharge was monitored. It was seen that hydrogen was simultaneously absorbed by the MH pellet electrode during discharge at higher pressures, and that the pellet released some hydrogen from the bulk when discharged at lower pressures. Electrochemical impedance spectroscopic analysis showed that the charge transfer step at the MH anode was influenced by the magnitude of hydrogen pressure. The higher hydrogen pressure resulted in a smaller semicircle and therefore a smaller charge transfer impedance.