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.