Reactive destabilization and bidirectional catalyzation for reversible hydrogen storage of LiBH4 by novel waxberry-like nano-additive assembled from ultrafine Fe3O4 particles

LiBH4 containing 18.5 wt.% H2 is an attractive high-capacity hydrogen storage material, however, it suffers from high operation temperature and poor reversibility. Herein, a novel and low-cost bifunctional additive, waxberry-like Fe3O4 secondary nanospheres assembled from ultrafine primary Fe3O4 nanoparticles, is synthesized, which exhibits significant destabilization and bidirectional catalyzation towards (de)hydrogenation of LiBH4. With an optimized addition of 30 wt.% waxberry-like Fe3O4, the system initiated dehydrogenation below 100 °C and released a total of 8.1 wt.% H2 to 400 °C. After 10 cycles, a capacity retention of 70% was achieved, greatly superior to previously reported oxides-modified systems. The destabilizing and catalyzing mechanisms of waxberry-like Fe3O4 on LiBH4 were systematically analyzed by phase and microstructural evolutions during dehydrogenation and hydrogenation cycling as well as density functional theory (DFT) calculations. The present work provides new insights in developing advanced nano-additives with unique structural and multifunctional designs towards LiBH4 hydrogen storage.