Hydrogen storage thermodynamics and kinetics of as-cast Ce-Mg-Ni-based alloy  

作　　者：Yan Qi Xin Zhang Jun Li Dong-liang Zhao Shi-hai Guo Yang-huan Zhang 

机构地区：[1]Department of Functional Material Research,Central Iron and Steel Research Institute,Beijing 100081,China [2]China Rare Earth New Material(Weishan)Co..Ltd.,Jining 277600,Shandong,China [3]Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-Metal Resources,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China

出　　处：《Journal of Iron and Steel Research International》2024年第3期752-766,共15页

基　　金：supported by the National Natural Science Foundation of China(Nos.51871125,51761032,51901105 and 52001005);Major Science and Technology Innovation Projects in Shandong Province(2019JZZY010320);Natural Science Foundation of Inner Mongolia,China(2019BS05005);Inner Mongolia University of Science and Technology Innovation Fund(2019QDL-B11).

摘　　要：The reaction kinetics of alloys based on magnesium are known to be greatly improved by the partial substitution of Mg with rare earths and transition metals,particularly Ni.The enhanced superficial hydrogen dissociation rate,the weakened Mg-H bond and the lower activation energy following element replacement are thought to be related to the better performance.The experimental alloys Ce5Mg_(95-x)Ni_(x)(x=5,10,15)were smelted by the vacuum induction melting.The phase transformation and structural evolution of experimental alloys before and after reaction with hydrogen were char-acterized by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.The cast specimens contain CeMg_(12),Mg and Mg_(2)Ni phases,and the increase in Ni content results in an obvious growth of Mg_(2)Ni phase.The isothermal and non-isothermal hydrogenation and dehydrogenation kinetics of the experimental specimens were investi-gated using the Sievert apparatus,differential scanning calorimetry and thermal gravimetric analyzer.The activation energy may be calculated using the Arrhenius and Kissinger equations.The experimental alloys have been shown to have good activation properties,with a reversible hydriding and dehydriding capacities of around 5.0 wt.%in the first cycle.The initial dehydrogenation temperature of MgH_(2) decreases from 557.5 to 537.7 K with changing Ni content from 5 to 15 at.%.The dehydrogenation activation energy also reduces from 77.09 to 62.96 kJ/mol,which explains the improved hydrogen storage performance caused by Ni substitution.It can be shown that the impact of Ni on the decomposition enthalpy of MgH_(2) is quite modest,with the absolute enthalpy(ΔHr)only decreasing from 78.48 to 76.15 kJ/mol.

关 键 词：Mg-based alloy Ni content Hydrogen storage kinetics Thermodynamic property Activation energy 

分 类 号：TG139[一般工业技术—材料科学与工程]