The PrMg12-type composite alloy of PrMg_(11)Ni + x wt% Ni (x=100,200) with an amorphous and nanocrystalline microstructure were synthesized through the mechanical milling.Effects of milling duration and Ni content on ...The PrMg12-type composite alloy of PrMg_(11)Ni + x wt% Ni (x=100,200) with an amorphous and nanocrystalline microstructure were synthesized through the mechanical milling.Effects of milling duration and Ni content on the microstructures and electrochemical hydrogen storage performances of the ball-milled alloys were methodically studied.The ball-milled alloys obtain the optimum discharge capacities at the first cycle.Increasing Ni content dramatically enhances the electrochemical property of alloys.Milling time varying may obviously impact the electrochemical performance of these alloys.The discharge capacities show a significant upward trend with milling duration prolonging,but milling for a longer time more than 40 h induces a slight decrease in the discharge capacity of the x=200 alloy.As milling duration increases,the cycle stability clearly lowers,while it first declines and then augments under the same condition for the x=200 alloy.The high-rate discharge abilities of the ball-milled alloys show the optimum values with milling time varying.展开更多
Nanocrystalline and amorphous LaMg_（12）-type LaMg_（11）Ni ＋ x wt% Ni（x = 100, 200） alloys were synthesized by mechanical milling. Effects of Ni content and milling time on the gaseous and electrochemical hydroge...Nanocrystalline and amorphous LaMg_（12）-type LaMg_（11）Ni ＋ x wt% Ni（x = 100, 200） alloys were synthesized by mechanical milling. Effects of Ni content and milling time on the gaseous and electrochemical hydrogen storage kinetics of as-milled alloys were investigated systematically. The electrochemical hydrogen storage properties of the as-milled alloys were tested by an automatic galvanostatic system. And the gaseous hydrogen storage properties were investigated by Sievert apparatus and a differential scanning calorimeter（DSC） connected with a H_2 detector. Hydrogen desorption activation energy of alloy hydrides was estimated by using Arrhenius and Kissinger methods. It is found that the increase of Ni content significantly improves the gaseous and electrochemical hydrogen storage kinetic performances of as-milled alloys. Furthermore, as ball milling time changes, the maximum of both high rate discharge ability（HRD） and the gaseous hydriding rate of as-milled alloys can be obtained. But the hydrogen desorption kinetics of alloys always increases with the extending of milling time. Moreover, the improved gaseous hydrogen storage kinetics of alloys are ascribed to a decrease in the hydrogen desorption activation energy caused by increasing Ni content and milling time.展开更多
Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diff...Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diffraction technique, and the spectrum features were identified by UV-Vis and Raman spectroscopy, respectively. It was observed that the cell parameters were first increased then decreased by increasing the doped ions content. The phase separation was detected when the dopant concentration reached to x=0.30. UV-Vis spectrum showed that the width of the band gap gradually reduced by increasing the doped content, and the solid solubility was determined to be x=0.20. The Raman technique displayed that the peak position of F2g mode gradually shifted to lower frequencies from 465 cm^–1 for x=0.00 to 440 cm^–1 for x=0.20. The catalytic effects of Ce1-x（Fe0.5Eu0.5）xO2-δsolid solutions on the electrochemistry properties of Mg2Ni/Ni were measured by mixing them together via ball milling technique. The electrochemical properties of the Mg_2Ni/Ni-Ce1-x（Fe0.5Eu0.5）xO2-δcomposites showed that the maximum discharge capability Cmax and the cycle stability were improved obviously. Meanwhile, the EIS characteristic also indicated that the doped solid solutions could enhance the rate of charge transfer on the surface of alloy. The catalytic effect of the solid solutions was speculated to rely on both the concentration of oxygen vacancies and the cell volumes of the solid solutions.展开更多
基金Funded by National Natural Science Foundation of China(Nos.51871125,51901105 and 51761032)Inner Mongolia Natural Science Foundation(No.2019BS05005)。
文摘The PrMg12-type composite alloy of PrMg_(11)Ni + x wt% Ni (x=100,200) with an amorphous and nanocrystalline microstructure were synthesized through the mechanical milling.Effects of milling duration and Ni content on the microstructures and electrochemical hydrogen storage performances of the ball-milled alloys were methodically studied.The ball-milled alloys obtain the optimum discharge capacities at the first cycle.Increasing Ni content dramatically enhances the electrochemical property of alloys.Milling time varying may obviously impact the electrochemical performance of these alloys.The discharge capacities show a significant upward trend with milling duration prolonging,but milling for a longer time more than 40 h induces a slight decrease in the discharge capacity of the x=200 alloy.As milling duration increases,the cycle stability clearly lowers,while it first declines and then augments under the same condition for the x=200 alloy.The high-rate discharge abilities of the ball-milled alloys show the optimum values with milling time varying.
基金Funded by the National Natural Science Foundation of China(Nos.51471054,51761032,and 51371094)the Natural Science Foundation of Inner Mongolia,China(No.2015MS0558)
文摘Nanocrystalline and amorphous LaMg_（12）-type LaMg_（11）Ni ＋ x wt% Ni（x = 100, 200） alloys were synthesized by mechanical milling. Effects of Ni content and milling time on the gaseous and electrochemical hydrogen storage kinetics of as-milled alloys were investigated systematically. The electrochemical hydrogen storage properties of the as-milled alloys were tested by an automatic galvanostatic system. And the gaseous hydrogen storage properties were investigated by Sievert apparatus and a differential scanning calorimeter（DSC） connected with a H_2 detector. Hydrogen desorption activation energy of alloy hydrides was estimated by using Arrhenius and Kissinger methods. It is found that the increase of Ni content significantly improves the gaseous and electrochemical hydrogen storage kinetic performances of as-milled alloys. Furthermore, as ball milling time changes, the maximum of both high rate discharge ability（HRD） and the gaseous hydriding rate of as-milled alloys can be obtained. But the hydrogen desorption kinetics of alloys always increases with the extending of milling time. Moreover, the improved gaseous hydrogen storage kinetics of alloys are ascribed to a decrease in the hydrogen desorption activation energy caused by increasing Ni content and milling time.
基金Project supported by the National Natural Science Foundation of China(51501059)Talent Incubation Funding of School of Materials and Metallurgy and Inner Mongolia University of Science and Technology(2014CY012)
文摘Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diffraction technique, and the spectrum features were identified by UV-Vis and Raman spectroscopy, respectively. It was observed that the cell parameters were first increased then decreased by increasing the doped ions content. The phase separation was detected when the dopant concentration reached to x=0.30. UV-Vis spectrum showed that the width of the band gap gradually reduced by increasing the doped content, and the solid solubility was determined to be x=0.20. The Raman technique displayed that the peak position of F2g mode gradually shifted to lower frequencies from 465 cm^–1 for x=0.00 to 440 cm^–1 for x=0.20. The catalytic effects of Ce1-x（Fe0.5Eu0.5）xO2-δsolid solutions on the electrochemistry properties of Mg2Ni/Ni were measured by mixing them together via ball milling technique. The electrochemical properties of the Mg_2Ni/Ni-Ce1-x（Fe0.5Eu0.5）xO2-δcomposites showed that the maximum discharge capability Cmax and the cycle stability were improved obviously. Meanwhile, the EIS characteristic also indicated that the doped solid solutions could enhance the rate of charge transfer on the surface of alloy. The catalytic effect of the solid solutions was speculated to rely on both the concentration of oxygen vacancies and the cell volumes of the solid solutions.
