Enhanced hydrogen storage performances of LiBH4 modified with three-dimensional porous fluorinated graphene

Novel fluorinated graphene (FG) nano-sheets with three-dimensional (3D) porous structure were synthesized by one-pot hydrothermal reaction , and then ball milled with LiBH 4 to prepare the hydrogen storage composite material. The LiBH 4 with 20 wt.% FG composite begins to release hydrogen at 204 °C, 120 °C lower than that of pure LiBH 4 . Moreover, it can release 3.45 wt.% hydrogen at 400 °C within 1000 s, which is 2.57 times faster than pure LiBH 4 . The reversibility of the LiBH 4 –FG composite also has been enhanced, its absorption capacity still reaches 78.6% of initial hydrogen uptake at the 4th cycle. According to the phase composition analyses, F – can partially substitute the anionic H in LiBH 4 or LiH, resulting in a favorable thermodynamic modification. Additionally, the activation energy ( E a ) of hydrogen desorption of LiBH 4 is reduced from 181.80 kJ/mol to 130.87 kJ/mol. The remarkably improved hydrogen storage performances of LiBH 4 are largely attributed to the combined effects of the nano-modifying and the function of F anion of the FG.