Rare earth-Mg-Ni-based alloys with superlattice structure for electrochemical hydrogen storage

The rapid development of Ni-MH batteries urgently needs advanced hydrogen storage alloys as negative electrodes. Rare earth-Mg-Ni-based (R-Mg-Ni-based) hydrogen storage alloys with superlattice structures possess high capacity, good electrochemical properties, moderate hydrogen equilibrium pressure and environment-friendliness, making them the attractive alloys for high-performance Ni-MH batteries. This review focuses on the progress in the superlattice R-Mg-Ni-based hydrogen storage alloys. The structural characteristics, hydrogen storage thermodynamics and kinetics, and approaches for improving electrochemical properties are highlighted. Preparation techniques and composition optimization as the key factors for tuning the electrochemical performance of R-Mg-Ni-based alloys are systematically summarized in this review. New ideas and approaches are still required for developing R-Mg-Ni-based alloys with higher energy density, longer cycle life, better kinetics and lower cost. The challenges and future directions in developing high-performance Ni-MH batteries are discussed as well. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The rapid development of Ni-MH batteries requires advanced hydrogen storage alloys as negative electrodes, and rare earth-Mg-Ni-based hydrogen storage alloys with superlattice structures are attracting attention due to their high capacity and good electrochemical properties. Preparation techniques and composition optimization are highlighted as key factors in tuning the electrochemical performance of these alloys. New ideas and approaches are needed for developing high-performance Ni-MH batteries with higher energy density and longer cycle life.