Analysis of hydrogen storage alloy negative electrodes by potential step method

Large decrease in discharge capacity of hydrogen storage alloy negative ele ctrodes was observed by assembling with nickel hydroxide positive electrode s containing cadmium. From the relationship between discharge rate and disc harge capacity of the negative electrode, and analysis by potential step me thod, the mechanism of this phenomenon was presumed to be as follows: 1) Cadmium in the positive electrodes dissolves into an electrolyte, and th en transfers on the surface of the hydrogen storage alloy particles. 2) Transferred cadmium impedes hydrogen diffusion between the inside of the alloy and the surface reaction sites where charge/discharge reaction takes place. Therefore, remarkable decrease in the discharge capacity of the neg ative electrode is observed.