Improvement of Hydrogen Storage Properties of the Li–Mg–N–H System by Addition of LiBH4

Significant improvements in the hydrogen desorption/absorption properties of the Li–Mg–N–H system have been achieved by adding a small amount of LiBH4. The onset as well as the peak temperatures of hydrogen desorption shift to lower temperatures. Five wt % of hydrogen can be fully desorbed at 140 °C and reabsorbed at 100 °C. The kinetics of hydrogen desorption as well as absorption were found to be 3 times as fast as the pristine system. Thermodynamic analyses show that the temperature for equilibrium desorption pressure at 1 bar was 70 °C, which is about 20 °C lower than the pristine system. The enhancement in the hydrogen sorption properties was attributed to the weakening of N−H bonding in the metal amide molecules.