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基于2LiNH_2-MgH_2二元体系,利用机械球磨法制备了3LiNH_2-MgH_2-2LiH三元体系,并研究了其放氢性能和机理。结果表明,LiH的添加明显改善了材料的微观结构,抑制了样品颗粒团聚,进而使放氢温度降低了30℃。与二元体系相比,在300℃下放氢量增加了21%,同时成功抑制了副产物氨气的释放。对三元体系添加KH进行催化改性,使得材料的放氢温度进一步降低。此外,对材料的放氢性能与固体样品的热扩散性能之间建立了关联,阐述了随热扩散系数的增加,材料的放氢性能随之提高的机理。
Based on the binary system of 2LiNH_2-MgH_2, 3LiNH_2-MgH_2-2LiH ternary system was prepared by mechanical ball milling and its hydrogen-releasing property and mechanism were studied. The results show that the addition of LiH significantly improves the microstructure of the material and inhibits the agglomeration of the sample particles, which in turn reduces the hydrogen release temperature by 30 ℃. Compared with the binary system, the amount of hydrogen released at 300 ℃ increased by 21%, while successfully inhibiting the by-product ammonia release. Catalytic modification of ternary system by adding KH, making the material further reduce the hydrogen release temperature. In addition, the relationship between the hydrogen desorption properties of the material and the thermal diffusivity of the solid sample is established. The mechanism that the hydrogen desorption performance of the material increases with the increase of the thermal diffusion coefficient is described.