Cycle stability improvement of La-Mg-Ni based alloys via composite method

La-Mg-Ni based alloys have a high hydrogen storage capacity, but their cycle stability is usually poor. In this work, a series of composites were synthesized by mixing La-Mg-Ni based alloys with a commercial AB₅ type alloy. The aim was to investigate the effects of AB₅ additions and ball milling treatment in improving the cycle stability of La-Mg-Ni based alloys, while maintaining a substantial and reversible hydrogen storage capability. It was found that the cycle stability was greatly influenced by the amount of AB₅ added, but the effect of ball milling pre-treatment was small. While the increase in AB₅ content was beneficial, the cost of the composite also went up accordingly. In light of these challenges, a feasibility study was conducted to optimize the compositions. The results suggested that the composite with a 50 wt% of AB₅ addition was the optimum compositions in maximizing the hydrogen storage capacity and cycle stability, while minimizing the cost up to 20% as compared with AB₅ alone.