In Situ Generation and Stabilization of Multiple Catalysts by Introducing a Graphene-Supported FeF₂/FeO_X Additive for Enhancing the Hydrogen Storage of LiBH₄

LiBH 4 has attracted significant interest due to its high-hydrogen storage capacity (18.5 wt % H 2 ). 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 FeF 2 /FeO X additive (FeF 2 /FeO X @G) is prepared and introduced into LiHB 4 by a simple ball-milling. With an optimized LiBH 4 -to-FeF 2 /FeO X @G weight ratio of 7:3, the 7LiBH 4 -3(FeF 2 /FeO X @G) system starts dehydrogenation at a low temperature of 100 °C below and 8.7 wt % H 2 is released upon heating to 400 °C, while 1.1 wt % H 2 is released for pristine LiBH 4 . Moreover, the system releases rapidly 7.0 wt % H 2 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, Li 3 BO 3, and Fe 2 B during the first dehydrogenation process acted as a synergistic catalysis, effectively improving the reversible hydrogen storage of LiBH 4 . This work provides insights into the design of unique additives to introduce multiple catalyst synergies to enhance the hydrogen storage performance of LiBH 4 .