A new strategy to remarkably improve the low-temperature reversible hydrogen desorption performances of LiBH4 by compositing with fluorographene

LiBH4 is a promising hydrogen storage material for its large capacity. However, high desorption temperature, sluggish kinetics and demanding rehydrogenation severely hinder its practical use. Surface functional groups of graphene in many cases are treated as effective approaches to obtain some kinds of excellent properties of energy storage materials. In the current work, a new facile and effective strategy to improve the reversible hydrogen desorption properties of LiBH4 is proposed by composing with functionalized graphene to form the LiBH4-fluorographene composite. The fluorographene (FG) nanosheets are successfully exfoliated from fluorographite (FGi) and composed with LiBH4. It is demonstrated that the FG can remarkably improve the hydrogen desorption thermodynamics, kinetics and reversibility of LiBH4 via reactant destabilization method. An extremely fast hydrogen desorption process with a high capacity of 8.2 wt.% at 148.1 °C is achieved in the LiBH4-50FG composite. Further research reveals that the enhancement actually roots in the strengthened interfacial interaction between LiBH4 and exfoliated FG. Moreover, it is confirmed that the LiBH4-40FG composite exhibits a significantly enhanced reversible hydrogen desorption capacity of 7.2 wt.% and LiBH4 is regenerated. Such enhanced reversible hydrogen desorption properties are ascribed to the strengthened interfacial interactions between LiBH4 and FG with large surface, as well as the formation of LiHxF1−x phase.