In-situ constructed destabilization reaction of LiBH4 wrapped with graphene toward stable hydrogen storage reversibility

Abstract

Building destabilization reaction of LiBH4 with high gravimetric and volumetric capacity has been regarded as one of the most effective ways to improve its hydrogen storage performance. These destabilization reactions, however, suffer from low efficiency and severe phase separation upon hydrogen storage, resulting in poor reversibility of LiBH4. Herein, the construction of LiBH4 destabilized by Al wrapped by graphene is realized by an in-situ solid–gas reaction of LiH and Al resulting from the dehydrogenation of LiAlH4 and diborane. Owing to the uniform formation of LiH around Al nanoparticles on a molecular level, the homogeneous distribution of LiBH4 around Al nanoparticles with intimate contact could be achieved, which, coupled with the significant decrease of their particle sizes down to the nanometer size, effectively promotes the destabilization reaction between LiBH4 and Al. As a result, a single-step dehydrogenation reaction between LiBH4 and Al towards the complete dehydrogenation of LiBH4 with the formation of AlB2 and AlLi is demonstrated at 400°C. More importantly, induced by the enhanced destabilization reaction efficiency between LiBH4 and Al, the complete dehydrogenation and hydrogenation of LiBH4 with a reversible capacity of 4.49 wt% after 5 cycles could be well preserved owing to the structural support role of graphene.