Effect of MgCl2 additives on the H-desorption properties of Li–N–H system

Li–N–H system, as a representative of metal-N–H system, is regarded as one of the most promising hydrogen storage materials. Motivated by the ammonia mediated mechanism of Li–N–H system, the effect of MgCl2 (which is an effective NH3 sorbent) on this system is systematically investigated in this work. Three different mechanisms are proposed to explain the effects of MgCl2 with different amount in the improvement of Li–N–H system. With small amount (<4 mol%), MgCl2 can improve the H-desorption properties of Li–N–H system as an NH3 sorbent. When the amount of MgCl2 increases, the H-desorption properties of Li–N–H system can be improved further though Mg2+ solid solution into LiNH2. With the amount of MgCl2 more than 25 mol%, the Li–N–H system changes into Li–Mg–N–H system by the reaction between MgCl2 and LiNH2. The Li–Mg–N–H system formed by this reaction exhibits a much better property than those of Li–Mg–N–H system reported before. It may provide a new idea to improve the metal-N–H system to meet the requirement of practical application.