Degradation behaviors of La–Mg–Ni-based metal hydride alloys:structural stability and influence on hydrogen storage performances
来源期刊：Acta Metallurgica Sinica2018年第9期
论文作者：Yi-Ming Li Bao-Yu Duan Zhuo-Cheng Liu Yang-Huan Zhang Hui-Ping Ren
文章页码：897 - 909
摘 要：The present work focuses on the structural stability upon hydrogenation of three typical La–Mg–Ni-based alloys:La2-Mg Ni9,La3Mg Ni14and La4Mg Ni19.Structural changes during gaseous and electrochemical cycles were characterized,and the influence of the structure distortion on the hydrogen storage properties was concerned.Hydrogen-induced amorphization（HIA）and disproportionation of the three alloys have occurred during both the gaseous and electrochemical cycles.Structural stability of the phase structures in the La–Mg–Ni system is found to follow the order:La Ni5-[（La,Mg）5Ni19[（La,Mg）2Ni7[（La,Mg）Ni3[（La,Mg）Ni2.HIA increases thermal stability of the metal hydrides and difficulty to dehydrogenation and leads to degradation of both the gaseous and electrochemical capacities.Interestingly,La2Mg Ni9with poor stability presents elevated discharge capability even at 60°C which can be attributed to increase in the hydrogen desorption capability and inhibition of the self-discharge induced by severe HIA at higher temperatures.In addition,HIA in the electrochemical reactions is obviously weaker than the extent during the gaseous cycles,which is mainly due to the slower hydrogenation speed.The development of HIA in the gaseous and electrochemical process is considered to follow the direct and gradual modes,respectively.
Yi-Ming Li1，Bao-Yu Duan2，Zhuo-Cheng Liu1，Yang-Huan Zhang1，Hui-Ping Ren1
1. Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources,Inner Mongolia University of Science and Technology2. Analytical and Testing Center,Inner Mongolia University of Science and Technology
摘 要：The present work focuses on the structural stability upon hydrogenation of three typical La–Mg–Ni-based alloys:La2-Mg Ni9,La3Mg Ni14and La4Mg Ni19.Structural changes during gaseous and electrochemical cycles were characterized,and the influence of the structure distortion on the hydrogen storage properties was concerned.Hydrogen-induced amorphization（HIA）and disproportionation of the three alloys have occurred during both the gaseous and electrochemical cycles.Structural stability of the phase structures in the La–Mg–Ni system is found to follow the order:La Ni5-[（La,Mg）5Ni19[（La,Mg）2Ni7[（La,Mg）Ni3[（La,Mg）Ni2.HIA increases thermal stability of the metal hydrides and difficulty to dehydrogenation and leads to degradation of both the gaseous and electrochemical capacities.Interestingly,La2Mg Ni9with poor stability presents elevated discharge capability even at 60°C which can be attributed to increase in the hydrogen desorption capability and inhibition of the self-discharge induced by severe HIA at higher temperatures.In addition,HIA in the electrochemical reactions is obviously weaker than the extent during the gaseous cycles,which is mainly due to the slower hydrogenation speed.The development of HIA in the gaseous and electrochemical process is considered to follow the direct and gradual modes,respectively.
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