Core–shell nanostructured magnesium-based hydrogen storage materials: a critical review

Hydrogen holds the advantages of high gravimetric energy density and zero emission. Effective storage and transportation of hydrogen constitute a critical and intermediate link for the advent of widespread applications of hydrogen energy. Magnesium hydride (MgH₂) has been considered as one of the most promising hydrogen storage materials because of its high hydrogen storage capacity, excellent reversibility, sufficient magnesium reserves, and low cost. However, great barriers both in the thermodynamic and the kinetic properties of MgH₂ limit its practical application. Doping catalysts and nanostructuring are two facile but efficient methods to prepare high-performance magnesium (Mg)-based hydrogen storage materials. Core–shell nanostructured Mg-based hydrogen storage materials synergize the strengths of the above two modification methods. This review summarizes the preparation methods and expounds the thermodynamic and kinetic properties, microstructure and phase changes during hydrogen absorption and desorption processes of core–shell nanostructured Mg-based hydrogen storage materials. We also elaborate the mechanistic effects of core–shell nanostructures on the hydrogen storage performance of Mg-based hydrogen storage materials. The goal of this review is to point out the design principles and future research trends of Mg-based hydrogen storage materials for industrial applications.