Experimental investigation on lithium borohydride hydrolysis

Abstract

Lithium borohydride, one of the highest energy density chemical energy carriers, is considered as an attractive potential hydrogen storage material due to its high gravimetric hydrogen density (19.6%). Belonging to borohydride compounds, it presents a real issue to overcome aims fixed by the U.S. Department of Energy in the field of energy, and so crystallizes currently attention and effort to use this material for large scale civil and military applications. However, due to its important hygroscopicity, lithium borohydride is a hazardous material which requires specific handling conditions for industrial aspects. In order to understand much more the reaction mechanism involved between LiBH 4 and the water vapor which leads to the native material dehydrogenation, several experimental techniques such as X-ray Photoelectrons Spectroscopy (XPS), Raman spectroscopy, X-Ray Diffraction (XRD) or thermal analysis (TGA/DTA) were investigated. Indeed, depending on water stoichiometric coefficient, several reactions are suggested in literature but the lithium borohydride hydrolysis way reaction scheme is still uncertain. Investigations exhibited interesting results and, highlighted the formation of lithium metaborate dihydrate LiBO 2,2H 2O as hydrolysis product via such a solid–gas reaction.