Li3N-LiNH2体系的循环放氢性能
Dehydrogenation Properties of a Li3N-LiNH2 System
作者单位
肖 琪 南开大学新能源材料化学研究所天津市金属与分子基材料化学重点实验室天津 300071 
陈 志 南开大学新能源材料化学研究所天津市金属与分子基材料化学重点实验室天津 300071 
赵前永 南开大学新能源材料化学研究所天津市金属与分子基材料化学重点实验室天津 300071 
杨化滨 南开大学新能源材料化学研究所天津市金属与分子基材料化学重点实验室天津 300071 
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,在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%,100 min内完成总放氢量的86%。但在循环3周后,100 min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。
关键词: Li3N  LiNH2  球磨法  循环放氢性能  衰减原因
基金项目: 
Abstract: 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 Li2NH 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.
Keywords: Li3N  LiNH2  ball milling method  dehydrogenation property  deterioration mechanism
 
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肖 琪,陈 志,赵前永,杨化滨.Li3N-LiNH2体系的循环放氢性能[J].无机化学学报,2013,29(2):237-242.
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