A study on improving the cycling stability of (Ti_0.8Zr_0.2)(V_0.533Mn_0.107Cr_{0.1 6}Ni_0.2)₄ hydrogen storage electrode alloy by means of annealing treatment: II. Effects on the electrochemical properties

In this part of our study, the effects of annealing treatment on the electrochemical properties of the (Ti_0.8Zr_0.2)(V_0.533Mn_0.107Cr_{0.1 6}Ni_0.2)₄ hydrogen storage electrode alloy are reported. The annealing treatment effectively improves the discharge capacity, the high rate dischargeability and the cycle life of the alloy. The association of the improvement in electrochemical properties with the changes in alloy structures after annealing treatment is discussed. The variations of the exchange current density I₀ and the limiting current density I_L by annealing treatment correlates well with the variation of the high rate dischargeability. However, the annealing treatment at the temperature studied does not affect the activation property of the alloy very much as all electrodes made of the alloys, either as casted or annealed, can be activated in a small number of charge-discharge cycles.