Investigation of the capacity degradation mechanism of La–Mg–Ca–Ni AB3-type alloy

In this paper, the cyclic stabilities and the mechanism of capacity decay of (La0.65Ca0.35) (Mg1.32Ca0.68)Ni9 AB3-type alloys were specifically clarified, which have seldom been studied previously. The results indicated that AB3 phase in the La–Mg–Ca–Ni AB3-type alloys decomposed after repeated hydrogen sorption cycles, due to the serious mismatch of AB2 and AB5 subunits. In addition, we evidently found that the formation of MgNi2 owing to the decomposition of AB3 phase was mainly responsible for the capacity decay, which might shed light on the further investigation of AB3-type alloys.