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.