THE TIV3NI0.56 HYDRIDE ELECTRODE - ITS ELECTROCHEMICAL AND CYCLE LIFECHARACTERIZATION

Charge/discharge cycle tests for the TIV3Ni0.56 electrode were conduct ed in order to investigate the processes of activation and deteriorati on. Cracking formation was observed to occur across the alloy grain du ring the activation process. After a few more cycles following the act ivation, smaller cracks were observed between the matrix and a seconda ry phase and also within the secondary phase. In the deterioration pro cess titanium and vanadium were found to dissolve selectively from bot h phases. When the electrode lost its discharge ability, titanium and vanadium in the secondary phase had almost disappeared, leaving the ni ckel layer, while the matrix phase still retained the original composi tion and hydrogen storage ability.