LaNi/sub 5-x/M/sub x/ alloys in rechargeable batteries: factors affecting cycle lifetimes

We have studied the effect that solute chemistry has on the cyclic lifetimes of AB/sub 5/ alloys in rechargeable cells. The results of a large number of measurements of cycle lifetimes of LaNi/sub 5-x/M/sub x/ electrodes are compiled. Correlations are made between the lifetimes, characterized by an exponential decay, and properties of the alloys and their constituents. It is found that the lifetimes show a strong dependence on the formation enthalpy of La with Ni/sub 1-x/5/M/sub x/5/ and a weak dependence on alloy volume expansion on hydriding.