中文摘要：

以等物质的量比的Li3N和LiNH2为起始原料，采用高能球磨法制得了Li—N—H体系，并研究了该体系循环放氢性能衰减的主要原因。XRD及FTIR结果表明，Li3N—LiNH2体系经首周吸氢后转变为LiNH2与LiH，存之后的吸放氢循环中，可逆的吸放氢过程发生在LiNH2与Li2NH之间相的转变。放氢动力学结果表明，Li3N—LiNH2体系在280℃下首周放氢量达5．6wt％，100min内完成总放氢量的86％。但在循环3周后，100min内的放氢量衰减至初始的36％。SEM及BET结果表明，放氢量的衰减主要是由于样品的烧结所致，但可通过再次球磨使其循环放氢性能恢复。

英文摘要：

A Li-N-H system has been prepared by ball milling with an equal molar ratio of Li3N and LiNH2 as the starting materials, and its decay mechanism during dehydrogenation cycles is investigated. XRD and FTIR results show that the reversible hydrogenation and dehydrogenation process is conducted in the following cycles between the LiNH2 and LizNH phases due to the phase transformation from Li3N to LiNH2 during the first hydrogenation process. The initial dehydrogenation capacity of the Li3N-LiNH2 system can reach 86% of the total amount of 5.6wt% H2 within 100 min at 280℃, while after three cycles it is reduced to 36%. SEM and BET results reveal that the capacity deterioration is mainly attributed to the sintering of the powders during hydrogenation and dehydrogenation cycles. However, the dehydrogenation properties can be recovered by repeated ball milling process.