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

Abstract

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.

Time-Dependent Multi-Particle Model Describing the Hydrogen Absorption of Nanocrystalline Magnesium Powders: A Case Study

“…The most detailed study on this issue was published by Yartys and co-workers who applied in situ X-ray diffraction to reveal the phase evolution of different Mg-based systems during hydrogentation-dehydrogation; however, no data are available on the crystallite size during isothermal absorption [75,76]. For more complex systems, such as Mg-TM [77] or complex hydrides [78], hydrogen uptake is usually a multi-step process; therefore, fitting the absorption curve by a single function is not possible.…”

Exceptional Hydrogen Uptake in Crystalline InxGa1–xN Semiconductors

“…In order to foresee any use in automotive hydrogen storage systems, it would be optimal to allow H desorption from the materials using only residual heat from a fuel cell; some modeling proposed a dehydrogenation enthalpy of 27 kJ molH 2 –1 as an optimal value for this application . To achieve reversible operations at more practical conditions with complex metal hydrides, catalysts and additives are normally used. − Two other strategies more recently explored to achieve realistic operation conditions are the destabilization of the lightweight complex hydrides using a second hydride (the so-called reactive hydride composites , ) and the nanoconfinement of the hydride to modify the kinetics and/or thermodynamics . It is also worth remarking here that several metal hydride materials involve safety risks (burning when exposed to air/water, toxicity, skin burns, etc.…”

Nanointerface Engineering of Metal Hydrides for Advanced Hydrogen Storage

“…The kinetic barriers of complex hydrides can be significantly reduced using various types of catalysts, and there have been several reviews describing the kinetic modification of complex hydrides by adding catalysts to NaAlH 4 , , LiAlH 4 , LiBH 4 , and Mg­(BH 4 ) 2 . In particular, the kinetics of NaAlH 4 has been extensively studied since it allows pure H 2 release and exhibits a good cyclability upon a proper modification, and numerous works demonstrated that the dehydrogenation kinetic barrier of NaAlH 4 can be reduced by employing catalyst doping or nanoconfinement.…”