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
The Mg90Ce5 RE5(RE=La,Ce,Nd)alloys were prepared by a vacuum induction furnace and their micro structure,phase transformation,thermodynamics and kinetics property were systematically studied by XRD,SEM,TEM,and PCT cha...The Mg90Ce5 RE5(RE=La,Ce,Nd)alloys were prepared by a vacuum induction furnace and their micro structure,phase transformation,thermodynamics and kinetics property were systematically studied by XRD,SEM,TEM,and PCT characterization methods.The result shows that the activated alloys are composed of Mg/MgH2 and corresponding REH2+x with nanoscale.The REH2+x grain with Ce and La or Nd functional group have lower nucleation potential barriers than CeH2+x grains as the nucleation location,thus improve the hydrogen absorption kinetics of these alloys among which the Mg90Ce5Nd5 alloy can absorb 90%of the hydrogen within 2 min at 320℃.In addition,the Mg90Ce10 alloy has the lowest activation energy with 103.2 kJ mol-1 and the fastest desorption kinetics,which can release 5 wt%of the hydrogen within 20 min at 320℃.This is a correlation with grain size and the in-suit formed CeH2.73/CeO2 interface.Moreover,the co-doping Ce and La or Nd can effectively disorganize the thermodynamic stability of Mg-based hydrogen storage alloys to a certain degree,but the dehydrogenation kinetics of that still is restricted by the recombination energy of hydrogen ions on the surface.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supported financially by the National Natural Science Foundations of China(Nos.51901105,51761032 and 51871125)the Natural Science Foundation of Inner Mongolia,China(No.2019BS05005)the Inner Mongolia University of Science and Technology Innovation Fund(2019QDL-B11)。
文摘The Mg90Ce5 RE5(RE=La,Ce,Nd)alloys were prepared by a vacuum induction furnace and their micro structure,phase transformation,thermodynamics and kinetics property were systematically studied by XRD,SEM,TEM,and PCT characterization methods.The result shows that the activated alloys are composed of Mg/MgH2 and corresponding REH2+x with nanoscale.The REH2+x grain with Ce and La or Nd functional group have lower nucleation potential barriers than CeH2+x grains as the nucleation location,thus improve the hydrogen absorption kinetics of these alloys among which the Mg90Ce5Nd5 alloy can absorb 90%of the hydrogen within 2 min at 320℃.In addition,the Mg90Ce10 alloy has the lowest activation energy with 103.2 kJ mol-1 and the fastest desorption kinetics,which can release 5 wt%of the hydrogen within 20 min at 320℃.This is a correlation with grain size and the in-suit formed CeH2.73/CeO2 interface.Moreover,the co-doping Ce and La or Nd can effectively disorganize the thermodynamic stability of Mg-based hydrogen storage alloys to a certain degree,but the dehydrogenation kinetics of that still is restricted by the recombination energy of hydrogen ions on the surface.
