Electrochemical studies mere performed on LaNi5-xSnx with 0 less than or equal to x less than or equal to 0.5. We measured the effect of the Sn substituent on the kinetics of charge-transfer and diffusion during hydrogen absorption and desorption, and the cyclic lifetimes of LaNi5-xSx electrodes in 250 mAh laboratory test cells. We report beneficial effects of making small substitutions of Sn for Ni in LaNi, on the performance of the metal hydride alloy anode in terms of cyclic lifetime, capacity, and kinetics. The optimal concentration of Sn in LaNi5-xSnx alloys for negative electrodes in alkaline rechargeable secondary cells was found to lie in the range 0.25 less than or equal to x less than or equal to 0.3.