Improved hydrogen storage properties of LiBH4 doped Li–N–H system

•The kinetics of hydrogen sorption of Li–N–H system was improved by LiBH4 addition.•The improvement of the hydrogen sorption may attribute to (LiNH2)x(LiBH4)(1−x).•Melted (LiNH2)x(LiBH4)(1−x) could transfer LiNH2 from solid state to molten state.

Remarkable improvement of hydrogen sorption properties of Li–N–H system has been obtained by doping with a small amount of LiBH4. The starting and ending temperatures of hydrogen desorption shift to lower temperatures and the release of NH3 is obviously restrained by 10 mol% LiBH4 doping. The kinetics of hydrogen desorption and absorption of Li–N–H system became faster by the addition of LiBH4. About 4 wt.% H2 can be released within 30 min and ∼4.8 wt.% H2 can be reabsorbed within 2 min by LiBH4 doped sample at 250 °C, while only 1.44 wt.% H2 is released and 2.1 wt.% is reabsorbed for pure Li–N–H system. The quaternary hydride (LiNH2)x(LiBH4)(1−x) formed by the reaction between LiBH4 and LiNH2 may contribute to the enhancement of the hydrogen sorption performances by yielding a ionic liquid phase and transferring LiNH2 from solid state to molten state with a weakened N–H bond.