Improvement in Power Density of Rechargeable Air Battery using Hydrogen Storage Alloy

摘要

A novel class of secondary battery comprising MH and air electrodes was developed for potential uses in high power density and high energy density applications such as electric or hybrid vehicles and power storage units supporting fuel cell and solar power systems. The air electrode consisted of nickel-based gas diffusion electrode using Ir_2Bi_2O_(7-z) as oxygen evolution and reduction catalyst. Coin-type of cells using alkaline solutions as electrolyte were designed and fabricated, and the charge-discharge behaviors were evaluated with constant current operation. The discharge voltage and power density were improved by using a thin film membrane, in which the electrolyte was impregnated, between the air and MH electrodes, and the maximum power density was comparable to that of commercially available Ni-MH secondary battery. The MH utilization and the current efficiency of a charge-discharge cycle were found to be more than 90%.