Interfacial Li-vacancy enhances hydrogen storage of nanoscale LiBH4

Nanoengineering has proved effective in tailoring thermodynamics and kinetics of LiBH 4 and improving its (de)hydrogenation under mild conditions. Constructing nanosized LiBH 4 on 2D graphene has been reported to enhance loading efficiency and hydrogen capacity. However, the chemical inertness of graphene makes it hard to alter the intrinsic characteristics of LiBH 4 , leading to limited performance improvement. Moreover, the structural stability of loaded LiBH 4 needs enhancement for longer cycle life. Herein, we develop a fluorinated porous graphene host in which the Li-philic fluorine atoms induce Li vacancies in LiBH 4 , reducing the reaction enthalpy and energy barrier for (de)hydrogenation; meanwhile, LiF formed in-situ acts as an interfacial bridge that stabilizes the nanostructure. An appreciable hydrogen release is achieved below 250 °C, with high capacity retention after 30 cycles. In addition, the porous channels ensure rapid hydrogen diffusion and superior kinetics in the compacted state, yielding a competitive volumetric hydrogen storage density of 76.2 g L −1 that is higher than liquefied hydrogen (~70 g L −1 ). This work presents feasible schemes for optimizing hydrogen storage performance of LiBH 4 and offers fresh insights on interfacial interaction mechanisms.