摘要
La–Y–Ni-based superlattice alloys demonstrate the potential as high-capacity anodes for Nickel-metal hydride batteries. However, the usual multi-phase structure formed in A 5 B 19 -type La–Y–Ni-based alloys makes precise investigations of composition-structure-performance relationships difficult. This work optimizes the quenching temperature to obtain the single-phase (La 0.33 Y 0.67 ) 5 Ni 17.6 Mn 0.9 Al 0.5 alloy with a hexagonal 2H–Pr 5 Co 19 structure. The single-phase alloy exhibits better overall electrochemical properties than multi-phase alloys, such as the maximum discharge capacity of 368.8 mAh g −1 , the capacity retention at the 200 th cycle of 73.4%, and the rate performance at a high discharge current of 1500 mA g −1 of 58.6%. The ex-situ X-ray diffraction research reveals that during charging, the single-phase alloy sequentially forms β and γ hydrides, with the β hydride exhibiting the highest lattice strain, mainly due to the asynchronous hydrogenation and expansion between [A 2 B 4 ] and [AB 5 ]-2 subunits. This work offers meaningful guidance for developing high-performance La–Y–Ni-based electrode alloys.
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