New dehydrogenation pathway of LiBH4 + MgH2 mixtures enabled by nanoscale LiBH4

Abstract

This study reports a new dehydrogenation pathway for the LiBH4 + MgH2 system. We find that in the presence of nanoscale LiBH4, the first dehydriding reaction is the decomposition of LiBH4 and the product from the LiBH4 decomposition in turn causes the hydrogen release from MgH2. The new reaction pathway has resulted in a large amount of hydrogen release from MgH2 below 150 °C. The discovery made in this study confirms the ab initio density functional theory calculations reported in the literature and a previous study showing that the new reaction pathway observed in this study can be achieved during high-energy ball milling of MgH2 at ambient temperature in conjunction with aerosol spraying of LiBH4 solution. The establishment of this new reaction pathway opens the door to make LiBH4 + MgH2 as a viable system for reversible hydrogen storage applications near 150 °C in the future.