Preparation and electrochemical characteristics of single-phase RE-Mg-Ni-based (RE = La, Pr, Nd, Sm) alloys with super-stacking structures

摘要

La—Mg—Ni-based hydrogen storage alloys are considered as promising negative electrode candidates to replace traditional AB_5-type alloys due to their large discharge capacity, however, their poor cycling stability restricts them further extensive application [1, 2]. To deeply study the capacity degradation mechanism and improve their cycling life, preparation of single-phase is basic and necessary, but this is of full of difficulty and reports on the single-phase alloys are rare. Our group succeeded in preparing AB_(3-), A_2B_(7-) and A_5B_(19)-type single-phase La—Mg—Ni super-stacking alloys by step-wise sintering and long-time annealing methods, and explored their formation and capacity degradation mechanism [3-6]. Moreover, we also prepared AB_(3-), A_2B_(7-) and A_5B_(19)-type single-phase super-stacking RE-Mg-Ni (RE — Pr, Nd, Sm) alloys by the above methods and revealed the cycling stability improvement mechanism. We expect our findings can provides the basis and inspire new thoughts for improving the cycling performance of RE—Mg—Ni-based hydrogen storage alloys.