Hajime Seri

Electrode characteristics of C15-type laves phasealloys

Abstract Extensive studies on hydrogen storage alloys such as LaNi5, MmNi5, Ti(Zr)−Ni etc. have been actively carried out for the negative electrodes of Ni−H2 batteries. The present authors, on the contrary, have focused on C14-type and C15-typeLaves phase alloys of the AB2 type based on TiCr2, TiMn2 and ZrMn2, and have succeeded in optimizing them for electrode materials which can supply a high energy density by inspecting the relation between the composition of the alloys, the P−C−T characteristics and the electrode performance. The Mn:Cr ratio, A:B ratio and addition of vanadium to the C15-type Lavesphase ZrMn0.6Cr0.2Ni1.2 were examined to investigate the alloy phases, hydride characteristics (P−C−T) and electrode performance. As a result, electrodes composed of such alloys as ZrCr0.8Ni1.2 andZrMn0.5Cr0.2V0.1Ni1.2 were found to provide a large discharge capacity in a cell test with an abundant electrolytic solution.