Highlighting the electrochemical performance of AB4-type single-phase La0.60Sm0.22Mg0.18Ni4.09Al0.09Mn0.10 hydrogen storage alloy for nickel metal hydride batteries

Rare earth–Mg–Ni-based superlattice structure alloys have garnered recognition as promising materials for hydrogen storage. However, their application is impeded by suboptimal cycling longevity. The novel AB₄-type alloy emerges as an attractive candidate, distinguished by its good structure stability, high rate capability, and long-term durability. Herein, we designed an AB₄-type La_0.60Sm_0.22Mg_0.18Ni_4.09Al_0.09Mn_0.10 alloy that manifests superior electrochemical performance. The obtained AB₄-type single-phase alloy delivers a high discharge capacity of 375.2 mAh·g⁻¹ and features outstanding discharge ability at high rates, maintaining 121 mAh·g⁻¹ even at a discharge rate of 6C. The excellent high-rate discharge performance can be attributed to its fast charge transfer and hydrogen diffusion kinetics. Moreover, the AB₄-type alloy maintains a capacity retention of 84.5% after 200 cycles and retains 55.7% of its capacity retention even after 500 cycles. This work provides a good alternative to hydrogen storage alloy with high power and long cycling durability performance for nickel metal hydride batteries.