LaNi/sub 5-x/M/sub x/ metal hydride alloys for alkaline rechargeable cells

Abstract

This work centers on making alloy modifications to LaNi/sub 5/ by replacing Ni with various metal elements. The primary goal of the alloy modifications is to stabilize the alloy during electrochemical cycling in an alkaline medium. The reasons that some elements promote cyclic stability are explored, and the relative magnitude of their effect is Ge>Sn>Si>Ga>Al>In>Ni. Other properties are determined for each alloy, such as maximum capacity, charge transfer kinetics, hydrogen diffusion, charge overpotentials, and charge efficiency. Alloy microstructural information is measured by X-ray diffraction, and gas-phase.