In Situ Generationand Stabilization of Multiple Catalystsby Introducing a Graphene-Supported FeF₂/FeO_X Additive for Enhancing the Hydrogen Storage of LiBH₄

LiBH₄ has attracted significant interest due to its high-hydrogen storage capacity (18.5 wt % H₂). However, its practical application is severely impeded by the high dehydrogenation temperature, sluggish hydrogen release kinetics, and poor reversibility. In this work, a graphene-supported rodlike FeF₂/FeO_X additive (FeF₂/FeO_X@G) is prepared and introduced into LiHB₄ by a simple ball-milling. With an optimized LiBH₄-to-FeF₂/FeO_X@G weight ratio of 7:3, the 7LiBH₄-3(FeF₂/FeO_X@G) system starts dehydrogenation at a low temperature of 100 °C below and 8.7 wt % H₂ is released upon heating to 400 °C, while 1.1 wt % H₂ is released for pristine LiBH₄. Moreover, the system releases rapidly 7.0 wt % H₂ at 350 °C within 80 min, and a dehydrogenation capacity of 5.5 wt % is reached after 10 reversible hydrogen absorption and desorption cycles. The in situ formed FeB, Li₃BO₃, and Fe₂B during the first dehydrogenation process acted as a synergistic catalysis, effectively improving the reversible hydrogen storage of LiBH₄. This work provides insights into the design of unique additives to introduce multiple catalyst synergies to enhance the hydrogen storage performance of LiBH₄.