La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-xFex （x=0-0.20） hydrogen storage alloys were synthesized by induction melting and subsequent annealing treatment, and phase structure and electrochemical characteristics were inves...La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-xFex （x=0-0.20） hydrogen storage alloys were synthesized by induction melting and subsequent annealing treatment, and phase structure and electrochemical characteristics were investigated. All alloys consist of a single LaNi5 phase with CaCu5 structure, and the lattice constant a and the cell volume （V） of the LaNi5 phase increase with increasing x value. The maximum discharge capacity gradually decreases from 319.0 mA？h/g （x=0） to 291.9 mA？h/g （x=0.20） with the increase in x value. The high-rate dischargeability at the discharge current density of 1200 mA/g decreases monotonically from 53.1% （x=0） to 44.2% （x=0.20）. The cycling stability increases with increasing x from 0 to 0.20, which is mainly ascribed to the improvement of the pulverization resistance.展开更多
Phase transformations and lattice expansions of MlNi_)3.75)Co_)0.75)Mn_)0.3)Al_)0.2) during the electrochemical hydriding-dehydriding process were investigated using in-situ X-ray diffraction. An intermediate hydride ...Phase transformations and lattice expansions of MlNi_)3.75)Co_)0.75)Mn_)0.3)Al_)0.2) during the electrochemical hydriding-dehydriding process were investigated using in-situ X-ray diffraction. An intermediate hydride γ phase between the hydrogen solid solution α phase and fully hydrided β phase can be observed during the cycling. The formation of γ phase is related to the diffusion of hydrogen in the crystal grains. The lower the charge rate is, the higher the content of γ phase is. The phase transformations during the hydriding-dehydriding process can be described as )αα+γ+ββγ+αα.) The lattice expansion from α to β is discrete, while that from γ to β is continuous. The formation of γ phase can reduce the discrete lattice expansion from α to β by 30%.展开更多
The Co-S/x wt.% AB5 （x=0, 10, 20, 30） composite materials were prepared by simply mixing Co-S material fabricated by hy- drothermal method and AB5 alloy. The structure and morphology of the composite materials were ...The Co-S/x wt.% AB5 （x=0, 10, 20, 30） composite materials were prepared by simply mixing Co-S material fabricated by hy- drothermal method and AB5 alloy. The structure and morphology of the composite materials were characterized by XRD and SEM, respectively. The electrochemical properties of the composite electrodes were studied by the galvanostatic charge, dis- charge test and electrochemical impedance spectroscopy. The results showed that the Co-S/20 wt.% AB5 composite electrode showed the highest discharge capacity and the best cycling stability. The existence of the AB5 alloy improved the electro- chemical activity of composite electrodes, reduced the electrochemical polarization resistances and promoted the electrochem- ical conversion reaction between Co and Co（OH）2. In order to improve the utilization rate of active materials, 0.0! mol/L Na2S203 was added into the electrolyte. The electrochemical properties of the composite electrode were significantly enhanced. After fifty cycles, the discharge capacity of the composite electrode increased from 407 to 481.7 mAh/g and the capacity reten- tion increased from 79.7% to 91.2%.展开更多
基金Project (51001043) supported by the National Natural Science Foundation of ChinaProject (NCET2011) supported by Program for New Century Excellent Talents in University, China+4 种基金Project (201104390) supported by China Postdoctoral Science Special FoundationProject (20100470990) supported by China Postdoctoral Science FoundationProject (2012IRTSTHN007) supported by Program for Innovative Research Team (in Science and Technology) in the University of Henan Province, ChinaProject (2011J1003) supported by Baotou Science and Technology Project, ChinaProject (B2010-13) supported by the Doctoral Foundation of Henan Polytechnic University, China
文摘La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-xFex （x=0-0.20） hydrogen storage alloys were synthesized by induction melting and subsequent annealing treatment, and phase structure and electrochemical characteristics were investigated. All alloys consist of a single LaNi5 phase with CaCu5 structure, and the lattice constant a and the cell volume （V） of the LaNi5 phase increase with increasing x value. The maximum discharge capacity gradually decreases from 319.0 mA？h/g （x=0） to 291.9 mA？h/g （x=0.20） with the increase in x value. The high-rate dischargeability at the discharge current density of 1200 mA/g decreases monotonically from 53.1% （x=0） to 44.2% （x=0.20）. The cycling stability increases with increasing x from 0 to 0.20, which is mainly ascribed to the improvement of the pulverization resistance.
文摘Phase transformations and lattice expansions of MlNi_)3.75)Co_)0.75)Mn_)0.3)Al_)0.2) during the electrochemical hydriding-dehydriding process were investigated using in-situ X-ray diffraction. An intermediate hydride γ phase between the hydrogen solid solution α phase and fully hydrided β phase can be observed during the cycling. The formation of γ phase is related to the diffusion of hydrogen in the crystal grains. The lower the charge rate is, the higher the content of γ phase is. The phase transformations during the hydriding-dehydriding process can be described as )αα+γ+ββγ+αα.) The lattice expansion from α to β is discrete, while that from γ to β is continuous. The formation of γ phase can reduce the discrete lattice expansion from α to β by 30%.
基金supported by the National Natural Science Foundation of China(Grant No.51201089)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China(PAPD)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20133221110009)
文摘The Co-S/x wt.% AB5 （x=0, 10, 20, 30） composite materials were prepared by simply mixing Co-S material fabricated by hy- drothermal method and AB5 alloy. The structure and morphology of the composite materials were characterized by XRD and SEM, respectively. The electrochemical properties of the composite electrodes were studied by the galvanostatic charge, dis- charge test and electrochemical impedance spectroscopy. The results showed that the Co-S/20 wt.% AB5 composite electrode showed the highest discharge capacity and the best cycling stability. The existence of the AB5 alloy improved the electro- chemical activity of composite electrodes, reduced the electrochemical polarization resistances and promoted the electrochem- ical conversion reaction between Co and Co（OH）2. In order to improve the utilization rate of active materials, 0.0! mol/L Na2S203 was added into the electrolyte. The electrochemical properties of the composite electrode were significantly enhanced. After fifty cycles, the discharge capacity of the composite electrode increased from 407 to 481.7 mAh/g and the capacity reten- tion increased from 79.7% to 91.2%.
