Enhanced hydrogen storage properties of 1.1MgH 2 -2LiNH 2 -0.1LiBH 4 system with LaNi 5 -based alloy hydrides addition.

Significant improvements in the hydrogen sorption properties of the Li-Mg-N-H system have been achieved by adding a small amount of LiBH 4 . Herein, the hydrogen storage properties of the 1.1MgH 2 -2LiNH 2 -0.1LiBH 4 system are further enhanced by addition of LaNi 5 -based (LaNi 3.8 Al 0.75 Mn 0.45 , LaNi 4.5 Mn 0.5 , LaNi 4 Co) alloy hydrides. The refinement of the Li-Mg-B-N-H particles and the metathesis reaction are facilitated by adding LaNi 5 -based alloy hydrides during the ball milling process. The addition of LaNi 5 -based alloy hydrides can enhance the hydrogen sorption kinetics, reduce the dehydrogenation temperature and promote a more thorough dehydrogenation of the Li-Mg-B-N-H system. The LaNi 5 -based alloy hydrides are involved in hydrogen de/hydrogenation reaction. Among the three alloys, LaNi 4.5 Mn 0.5 makes the most obvious improvement on the reaction kinetics, and the dehydrogenation peak temperature is reduced by 12 °C, while the activation energy is reduced by 11% with 10 wt% LaNi 4.5 Mn 0.5 addition. The weakening of the N-H bond and the homogeneous distribution of the LaNi 5 -based alloy hydrides in the Li-Mg-B-N-H composite have important roles in the reduction of the desorption barrier and the kinetics enhancement.