Tailoring MgH2 for hydrogen storage through nanoengineering and catalysis

Hydrogen energy has been recognized as “Ultimate Power Source” in the 21st century, which could be the best solution to the looming energy crisis and climate degeneration in the near future. Due to its high safety, low price, abundant resources and decent hydrogen storage density, magnesium based solid-state hydrogen storage materials are becoming the leading candidate for onboard hydrogen storage. However, the high operation temperature and slow reaction rate of MgH2, as a result of the large formation enthalpy and high reaction activation energy, respectively, are the first and most difficult problems we need to face and overcome to realize its industrialization. Herein, a state-of-the-art review on tailoring the stable thermodynamics and sluggish kinetics of hydrogen storage in MgH2, particularly through nanoengnieering and catalysis is presented, aiming to provide references and solutions for its promotion and application. Promising methods to overcome the challenges faced by MgH2/Mg, such as bidirectional catalysts and nanoconfinement with in-situ catalysis are compared and the required improvements are discussed to stimulate further discussions and ideas in the rational design of MgH2/Mg systems with ability for hydrogen release/uptake at lower temperatures and cycle stability in the near future.