A nanoconfined-LiBH4 system using a unique multifunctional porous scaffold of carbon wrapped ultrafine Fe3O4 skeleton for reversible hydrogen storage with high capacity

Abstract LiBH4 with a capacity of 18.5 wt% H2, is a promising high-capacity hydrogen storage material; however, it suffers from high operation temperature and poor reversibility. Herein, a novel structural LiBH4 system prepared via a nanoconfinement technique, coupling with in-situ introduced catalysts, is developed. By using a unique passionfruit-like porous hybrid composed of carbon wrapped ultrafine Fe3O4 skeleton (p-Fe3O4@C) as scaffold, synergetic effects of nanoconfinement, catalysis and surface destablization are achieved, which significantly improve the overall hydrogen storage properties of LiBH4. With an optimized LiBH4 loading of 60 wt%, the confined system initiates dehydrogenation at a low temperature of 175 °C and rapidly desorbs 7.8 wt% H2 at 350 °C within 30 min. Moreover, the dehydrogenated system shows a high reversibility under relatively moderate hydrogenation conditions. A dehydrogenation capacity of 6.2 wt% remains after 20 cycles. The system can be flexibly compacted, showing a volumetric hydrogen density as high as 79.4 g L−1, where there is almost no dehydrogenation property deterioration compared with its powder counterpart. The present work provides new insights in developing advanced complex hydride-based hydrogen storage systems through functional and structural designs.