Composition optimization and electrochemical characteristics of Co-free Fe-containing AB5-type hydrogen storage alloys through uniform design
来源期刊：JOURNAL OF RARE EARTHS2012年第4期
论文作者：晁栋梁 陈云贵 朱昌荣 吴朝玲 朱丁
文章页码：361 - 366
摘 要：In order to reduce the cost of AB5-type hydrogen storage alloys, effects of substitution of Ce for La （A side） and Fe, Mn, Al for Ni （B side） on structural and electrochemical properties of （LaCe）1（NiFeMnAl）5 alloys were studied systematically. To make component uniform and operation easy, uniform design （UD） method was introduced into the study of composition optimization of Co-free Fe-containing AB5-type alloys for the first time. X-ray diffraction （XRD） results showed that the designed alloys were of single CaCu5-type structure phase. The replacement of Fe had a severe effect on electrochemical capacity, and the substitution of Fe and Al had a synergetic action among the unit cell volume, cycling stability and high rate discharge property. Interestingly, it was found that the hydrogen storage alloys with exces-sively high plateau pressure showed a tilted line in Nyquist plot instead of the semicircle, and the current decayed rapidly to near zero at the beginning of the step in constant potential step （CPS）, indicating that electrochemical impedance spectra （EIS） and CPS cannot accurately measure the electrochemical kinetics process of the hydrogen storage alloys with excessively high plateau pressure.
晁栋梁，陈云贵，朱昌荣，吴朝玲，朱丁
College of Materials Science and Engineering, Sichuan University
摘 要：In order to reduce the cost of AB5-type hydrogen storage alloys, effects of substitution of Ce for La （A side） and Fe, Mn, Al for Ni （B side） on structural and electrochemical properties of （LaCe）1（NiFeMnAl）5 alloys were studied systematically. To make component uniform and operation easy, uniform design （UD） method was introduced into the study of composition optimization of Co-free Fe-containing AB5-type alloys for the first time. X-ray diffraction （XRD） results showed that the designed alloys were of single CaCu5-type structure phase. The replacement of Fe had a severe effect on electrochemical capacity, and the substitution of Fe and Al had a synergetic action among the unit cell volume, cycling stability and high rate discharge property. Interestingly, it was found that the hydrogen storage alloys with exces-sively high plateau pressure showed a tilted line in Nyquist plot instead of the semicircle, and the current decayed rapidly to near zero at the beginning of the step in constant potential step （CPS）, indicating that electrochemical impedance spectra （EIS） and CPS cannot accurately measure the electrochemical kinetics process of the hydrogen storage alloys with excessively high plateau pressure.
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