Reversibly storing over 12 wt% H2 by a trilayered lithium borohydride nanocomposite commencing from 70ºC

Hydrogen storage in lithium borohydride (LiBH4) with high gravimetric and volumetric hydrogen densities has attracted intensive research interest. However, the high working temperatures and poor reversibility due to the high thermodynamic stability and kinetic barriers, limits its practical applications. Herein, we fabricate a unique trilayered nanostructure composed of layers of graphene support, Ni nanoclusters, and LiBH4 nanoparticles, through a layer-by-layer assembly approach. The Ni nanoclusters offer nucleation sites, separate LiBH4 nanoparticles from graphene, catalyze the formation of B-H bonds and eliminate the foaming effect. During hydrogenation, Ni cleaves H-H bonds and B clusters, creating additional hydrogen absorption sites and reducing the H adsorption energy of B, which lowers the hydrogen dissociation barrier, allowing reversible storage of approximately 12.27 wt% H2 by LiBH4 commencing from 70 ºC under 100 bar H2. This finding guides the design and fabrication of light-metal hydride nanostructures for practical on-board hydrogen storage applications.