Rare earth(RE)elements have been successfully utilized in solid-state hydrogen storage as hydrogen-absorbing elements with excellent hydrogen storage properties in terms of safety and efficiency.RE-Mg-based hydrogen s...Rare earth(RE)elements have been successfully utilized in solid-state hydrogen storage as hydrogen-absorbing elements with excellent hydrogen storage properties in terms of safety and efficiency.RE-Mg-based hydrogen storage materials with high magnesium content are considered to be one of the most promising hydrogen storage materials for application due to their high mass/volume hydrogen storage density,moderate required hydrogen pressure,good reversibility,non-toxicity,and harmlessness.Furthermore,RE-Mg-based materials with low magnesium content and superlattice structure show great potential for application in the field of solid-state hydrogen storage.They are also widely used as anode materials for nickel-metal hydride batteries.In this paper,we comprehensively summarized and evaluated the organization and hydrogen storage properties of different RE-Mg system alloys(Mg-RE,Mg-RE-TM(TM=transition metals),and superlattice-type RE-Mg-TM)and the catalytic effect and mechanisms of catalysts on RE-Mg system alloys.The interactions between the types of RE elements,the contents of RE elements,the crystal structures,and the catalysts with the microstructure morphology and hydrogen storage properties of RE-Mg-based hydrogen storage alloys were established.The intrinsic mechanisms between microstructure morphology,phase structure,phase composition,and hydrogen storage properties of alloys with different RE-Mg-based systems were elucidated.By comparing the differences and characteristics between the organizational structures and hydrogen storage properties of different RE-Mg systems,a feasible idea and solution for the rational design and development of RE-Mg-based alloys with high hydrogen storage capacity,low cost,and fast hydrogen absorption and desorption kinetics was proposed.展开更多
To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density,Mg−RE−TM(RE=rare earth,TM=metallic element)alloys have been extensively researc...To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density,Mg−RE−TM(RE=rare earth,TM=metallic element)alloys have been extensively researched and hold great promise.In this study,a series of Mg−RE−TM based Mg_(90)Y_(2)Ce_(2)Ni_(3)Al_(3-x)Sc_(x)(x=0,0.3,0.6,0.9,1.2)alloys were prepared.The addition of Sc element has been found to enhance the activation and kinetic properties of the alloy.Compared with the significant differences in the first four dehydrogenation curves of the Sc0 sample,the first activated dehydrogenation curve of the Sc1.2 alloy overlaps with the fully activated dehydrogenation curve.The dehydrogenation activation energy decreased from 96.56 kJ/mol in the Sc0 alloy to 63.69 kJ/mol in the Sc0.9 alloy.Through analysis of the microstructure,phase composition,and hydrogen absorption and desorption kinetics of the alloy,the mechanisms for improving the hydrogen storage properties of the alloy were elucidated.The nucleation-growth-impingement Avrami model was employed to accurately simulate the hydrogen storage kinetics.The results showed that stage II was prolonged and accelerated at high temperature,and the growth rate and hydrogen storage of stage I were increased at low temperature in hydrogen absorption.Microstructure analysis revealed the presence of Mg,CeMg_(12),Mg_(47)Y,and YNi_(2)Al_(3) phases in the Sc0 sample.Upon the addition of Sc element,a new phase,ScNiAl,was formed,and the coarse grain size of the main phase was significantly refined.This refinement provides faster diffusion channels for hydrogen atoms,accelerating the phase transition between Mg alloys and hydrides.The microstructure changes explain the improved activation properties,effective hydrogen absorption and desorption capacity,and kinetic properties of the Mg-based samples.展开更多
基金supported by the National Natural Science Foundation of China(51871125)the Major Programs of Central Iron and Steel Research Institute(No.23020230ZD).
文摘Rare earth(RE)elements have been successfully utilized in solid-state hydrogen storage as hydrogen-absorbing elements with excellent hydrogen storage properties in terms of safety and efficiency.RE-Mg-based hydrogen storage materials with high magnesium content are considered to be one of the most promising hydrogen storage materials for application due to their high mass/volume hydrogen storage density,moderate required hydrogen pressure,good reversibility,non-toxicity,and harmlessness.Furthermore,RE-Mg-based materials with low magnesium content and superlattice structure show great potential for application in the field of solid-state hydrogen storage.They are also widely used as anode materials for nickel-metal hydride batteries.In this paper,we comprehensively summarized and evaluated the organization and hydrogen storage properties of different RE-Mg system alloys(Mg-RE,Mg-RE-TM(TM=transition metals),and superlattice-type RE-Mg-TM)and the catalytic effect and mechanisms of catalysts on RE-Mg system alloys.The interactions between the types of RE elements,the contents of RE elements,the crystal structures,and the catalysts with the microstructure morphology and hydrogen storage properties of RE-Mg-based hydrogen storage alloys were established.The intrinsic mechanisms between microstructure morphology,phase structure,phase composition,and hydrogen storage properties of alloys with different RE-Mg-based systems were elucidated.By comparing the differences and characteristics between the organizational structures and hydrogen storage properties of different RE-Mg systems,a feasible idea and solution for the rational design and development of RE-Mg-based alloys with high hydrogen storage capacity,low cost,and fast hydrogen absorption and desorption kinetics was proposed.
基金National Natural Science Foundation of China(51871125)the Major Programs of Central Iron and Steel Research Institute(No.23020230ZD)for financial support of the work.
文摘To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density,Mg−RE−TM(RE=rare earth,TM=metallic element)alloys have been extensively researched and hold great promise.In this study,a series of Mg−RE−TM based Mg_(90)Y_(2)Ce_(2)Ni_(3)Al_(3-x)Sc_(x)(x=0,0.3,0.6,0.9,1.2)alloys were prepared.The addition of Sc element has been found to enhance the activation and kinetic properties of the alloy.Compared with the significant differences in the first four dehydrogenation curves of the Sc0 sample,the first activated dehydrogenation curve of the Sc1.2 alloy overlaps with the fully activated dehydrogenation curve.The dehydrogenation activation energy decreased from 96.56 kJ/mol in the Sc0 alloy to 63.69 kJ/mol in the Sc0.9 alloy.Through analysis of the microstructure,phase composition,and hydrogen absorption and desorption kinetics of the alloy,the mechanisms for improving the hydrogen storage properties of the alloy were elucidated.The nucleation-growth-impingement Avrami model was employed to accurately simulate the hydrogen storage kinetics.The results showed that stage II was prolonged and accelerated at high temperature,and the growth rate and hydrogen storage of stage I were increased at low temperature in hydrogen absorption.Microstructure analysis revealed the presence of Mg,CeMg_(12),Mg_(47)Y,and YNi_(2)Al_(3) phases in the Sc0 sample.Upon the addition of Sc element,a new phase,ScNiAl,was formed,and the coarse grain size of the main phase was significantly refined.This refinement provides faster diffusion channels for hydrogen atoms,accelerating the phase transition between Mg alloys and hydrides.The microstructure changes explain the improved activation properties,effective hydrogen absorption and desorption capacity,and kinetic properties of the Mg-based samples.
