THE DETERIORATION BEHAVIOR OF A METAL HYDRIDE ELECTRODE BASED ON THE V0.66TI0.22NI0.12 ALLOY

The deterioration behavior of a V0.66Ti0.22Ni0.12 alloy electrode duri ng charge-discharge cycling in KOH electrolyte and its degradation mec hanism were investigated. The alloy electrode was completely deteriora ted within 10 cycles. Coating the alloy particles with Ni or Cu improv ed to some extent the cycle life but the capacity for decay with cycli ng was still significant. The capacity for loss of the V0.66Ti0.22Ni0. 12 alloy electrode with cycling was ascribed to the dissolution of V a nd Ti (mainly V) from the near-surface region into the electrolyte and the formation of TiO2 layer on the alloy particle surface which resul ted in increases of the contact resistance between particles and the r eaction resistance on the alloy surface.