An Overview of the Recent Advances of Additive-Improved Mg(BH4)2 for Solid-State Hydrogen Storage Material

Recently, hydrogen (H2) has emerged as a superior energy carrier that has the potential to replace fossil fuel. However, storing H2 under safe and operable conditions is still a challenging process due to the current commercial method, i.e., H2 storage in a pressurised and liquified state, which requires extremely high pressure and extremely low temperature. To solve this problem, research on solid-state H2 storage materials is being actively conducted. Among the solid-state H2 storage materials, borohydride is a potential candidate for H2 storage owing to its high gravimetric capacity (majority borohydride materials release >10 wt% of H2). Mg(BH4)2, which is included in the borohydride family, shows promise as a good H2 storage material owing to its high gravimetric capacity (14.9 wt%). However, its practical application is hindered by high thermal decomposition temperature (above 300 °C), slow sorption kinetics and poor reversibility. Currently, the general research on the use of additives to enhance the H2 storage performance of Mg(BH4)2 is still under investigation. This article reviews the latest research on additive-enhanced Mg(BH4)2 and its impact on the H2 storage performance. The future prospect and challenges in the development of additive-enhanced Mg(BH4)2 are also discussed in this review paper. To the best of our knowledge, this is the first systematic review paper that focuses on the additive-enhanced Mg(BH4)2 for solid-state H2 storage.