Nickel metal hydride (Ni-MH) rechargeable batteries hold an important position in the new-energy vehicle market owing to their key technology advantages. Their negative electrode materials—hydrogen storage alloys (HSAs) are always on the spotlight and are the key to compete with the burgeoning Li-ion batteries. Here, for the first time we report a series of biphase supperlattice HSAs with a (La,Mg)₂Ni₇ matrix phase and a novel (La,Mg)₇Ni₂₃ secondary phase. The biphase alloys show discharge capacities of 402–413 mAh g⁻¹ compared with 376–397 mAh g⁻¹ of the other multi- or single-phase alloys. These values are among the highest for superlattice HSAs. In addition, the alloy with 15.4 wt.% (La,Mg)₇Ni₂₃ phase exhibits good high rate dischargeability due to the proper compromise between the amount of crystal boundaries and equilibrium plateau voltage. The cycling stability of the biphase alloys is lower than that of the single-phase alloy but is till higher than the multiphase alloy. The novel superlattice biphase alloys with superior overall electrochemical properties are expected to inspire further design and development of HSAs as advanced electrode materials for power batteries.

镍氢（Ni-MH）充电电池由于其关键技术优势而在新能源汽车市场中占有重要地位。他们的负极材料-储氢合金（HSA）一直备受关注，并且是与新兴的锂离子电池竞争的关键。在这里，我们首次报道了一系列具有（La，Mg）₂ Ni ₇基质相和新型（La，Mg）₇ Ni ₂₃次生相的双相超晶格HSA 。双相合金的放电容量为376–397 mAh g ^-1，而放电容量为402–413 mAh g ^-1其他多相或单相合金。这些值是超晶格HSA的最高值。另外，由于适当地折衷了晶体边界量和平衡平台电压，具有15.4重量％（La，Mg）₇ Ni ₂₃相的合金表现出良好的高倍率放电性能。双相合金的循环稳定性低于单相合金，但一直高于多相合金。具有优异整体电化学性能的新型超晶格双相合金有望激发HSA作为动力电池高级电极材料的进一步设计和开发。