ELECTROCHEMICAL CHARACTERISTICS OF NI-PD-COATED MMNI(5)-BASED ALLOY POWDER FOR NICKEL METAL HYDRIDE BATTERIES

Negative electrodes were made from a multicomponent alloy (Mm(0.9)Ti(0 .1)Ni(3.9)Mn(0.4)Co(0.4)Al(0.3)) powder coated with 10 wt.% palladium and nickel. The capacity decay of the Ni-Pd-coated alloy electrode was only 3% after 200 cycles compared with its saturated value at 27 degr ees C. Experimental Ni-MH batteries (AA size, 1 A h) using the Ni-Pd-c oated and uncoated alloy powders were assembled to clarify the dischar ge characteristics. The average discharge voltage of the battery using the Ni-Pd-coated alloy powder was 1.27 V at 0.4 C rate and the discha rge capacity at 3 C rate was 76% of the value at 0.4 C rate.