Gaseous hydrogen storage thermodynamics and kinetics of RE-Mg-Ni-based alloys prepared by mechanical milling  

作　　者：ZHANG Yang-huan YUAN Ze-ming YANG Tai BU Wen-gang HOU Zhong-hui ZHAO Dong-liang 张羊换;袁泽明;杨泰;卜文刚;侯忠辉;赵栋梁

机构地区：[1]Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources,Inner Mongolia University of Science and Technology [2]Department of Functional Material Research,Central Iron and Steel Research Institute

出　　处：《Journal of Central South University》2017年第4期773-781,共9页中南大学学报（英文版）

基　　金：Projects(51161015,51371094,51471054)supported by the National Natural Science Foundation of China

摘　　要：Nanocrystalline/amorphous La Mg11Ni+x Ni(x=100%, 200%, mass fraction) composite hydrogen storage alloys were synthesized by ball milling technology. The effects of Ni content and milling time on the gaseous hydrogen storage thermodynamics and dynamics of the alloys were systematically investigated. The hydrogen desorption properties were studied by Sievert's apparatus and a differential scanning calorimeter(DSC) connected with a H2 detector. The thermodynamic parameters(ΔH and ΔS) for the hydrogen absorption and desorption of the alloys were calculated by Van't Hoff equation. The hydrogen desorption activation energy of the alloy hydride was estimated using Arrhenius and Kissinger methods. The results indicate that a variation in the Ni content has a slight effect on the thermodynamic properties of the alloys, but it significantly improves their absorption and desorption kinetics performances. Furthermore, varying milling time clearly affects the hydrogen storage properties of the alloys. All the as-milled alloys show so fast hydrogen absorption rate that the absorbed amount in 10 min reaches to at least more than 95% of the saturated hydrogen absorption capacity. Moreover, the improvement of the gaseous hydrogen storage kinetics of the alloys is found to be ascribed to a decrease in the hydrogen desorption activation energy caused by increasing Ni content and prolong milling time.Nanocrystalline/amorphous La Mg11Ni+x Ni(x=100%, 200%, mass fraction) composite hydrogen storage alloys were synthesized by ball milling technology. The effects of Ni content and milling time on the gaseous hydrogen storage thermodynamics and dynamics of the alloys were systematically investigated. The hydrogen desorption properties were studied by Sievert's apparatus and a differential scanning calorimeter(DSC) connected with a H2 detector. The thermodynamic parameters(ΔH and ΔS) for the hydrogen absorption and desorption of the alloys were calculated by Van't Hoff equation. The hydrogen desorption activation energy of the alloy hydride was estimated using Arrhenius and Kissinger methods. The results indicate that a variation in the Ni content has a slight effect on the thermodynamic properties of the alloys, but it significantly improves their absorption and desorption kinetics performances. Furthermore, varying milling time clearly affects the hydrogen storage properties of the alloys. All the as-milled alloys show so fast hydrogen absorption rate that the absorbed amount in 10 min reaches to at least more than 95% of the saturated hydrogen absorption capacity. Moreover, the improvement of the gaseous hydrogen storage kinetics of the alloys is found to be ascribed to a decrease in the hydrogen desorption activation energy caused by increasing Ni content and prolong milling time.

关 键 词：hydrogen storage mechanical milling activation energy KINETICS 

分 类 号：U473.25[机械工程—车辆工程]