Regulation strategy of preparation methods for new spherical La-Y-Ni hydrogen storage alloy with ultra-long cycle lives

Abstract

La-Y-Ni-based alloys are high-performance superlattice rare-earth H2-storage electrode materials. However, their complex phase structural evolution results in poor electrochemical cycle lives. In this study, a gas atomization method develops to obtain spherical La-Y-Ni-based hydrogen storage alloys with high structural stability. The spherical La-Y-Ni powder exhibits a narrow particle size distribution between 30 and 75 μm and capacity retention over 60 % for 600 cycles. A three-dimensional particle insertion strain model and finite element simulations reveal the direct effects of the particle morphology on the stress distribution during hydrogen embedding. The spherical powder exhibits a uniform strain, good mechanical properties, and resistance against pulverization and damage. The new preparation strategy for spherical powders prominently regulates the [A₂B₄] subunit, decreasing the subunit mismatch and lattice strain, and improving the structural stability during the hydrogen absorption/desorption. In addition, the morphology regulation, phase composition controllability, platform characteristics and electrochemical properties investigate by comparing the use of gas atomization, casting, and rapid quenching. This study provides a new direction for developing high-performance spherical electrode materials.