Low‐Temperature Synthesis of LiBH₄ by Gas–Solid Reaction

Abstract

Abstract Strikingly simple : The low‐temperature and solvent‐free synthesis of LiBH 4 from LiH in a borane atmosphere at ambient pressures is reported. The results indicate that the formation of BH bonds is the limiting step for the formation of LiBH 4 from the elements. Therefore, the use of diborane as a starting reactant allows one to circumvent the reaction barrier for the BB bond dissociation and explains the rather moderate synthesis conditions. magnified image The solvent‐free synthesis of LiBH 4 from LiH in a borane atmosphere at 120 °C and ambient pressures is demonstrated. The source of borane is a milled LiBH 4 /ZnCl 2 mixture, in which Zn(BH 4 ) 2 is generated by a metathesis reaction. The yield of the reaction of about 74 % LiBH 4 shows that a bulk reaction is taking place upon borane absorption by LiH. This indicates that the formation of BH bonds is the limiting step for the formation of LiBH 4 from the elements. Therefore, the use of diborane as a starting reactant allows one to circumvent the reaction barrier for the BB bond dissociation and explains the rather moderate synthesis conditions.