Phase structure and electrochemical properties of La_0.7Ce_0.3Ni_3.75Mn_0.35Al_0.15Cu_{0.75?span style='font-style: italic'>x}(Fe_0.43B_0.57)_x hydrogen storage all

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• 作者：Baozhong Liu^a ; ^{bzliu@hpu.edu.cn} ; ^{b_z_liu@163.com} ; Mengjuan Hu^a ; Liqiang Ji^b ; Yanpin Fan^a ; Yongguang Wang^b ; Zhi Zhang^a ; Anming Li^a
• 关键词：Hydrogen storage alloy ; FeB alloy ; Phase structure ; Electrochemical property ; Ni/MH batteries
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 出版时间：5 March 2012
• 年：2012
• 卷：516
• 期：Complete
• 页码：53-57
• 全文大小：473 K

文摘

Microstructure and electrochemical characteristics of La_0.7Ce_0.3Ni_3.75Mn_0.35Al_0.15Cu_0.75?em>x(Fe_0.43B_0.57)_x hydrogen storage alloys have been investigated. XRD indicates that La_0.7Ce_0.3Ni_3.75Mn_0.35Al_0.15Cu_0.75 alloy consists of a single LaNi₅ phase with CaCu₅ structure. The alloys containing FeB are composed of LaNi₅ phase with CaCu₅ structure as matrix phase and La₃Ni₁₃B₂ phase as secondary phases, and the abundance of the secondary phase gradually increases with increasing FeB content. As x increases from 0.00 to 0.20, maximum discharge capacity of the alloy electrodes monotonically decreases from 314.0 to 290.4 mAh/g. Cycling stability of the alloy electrodes increases with increasing x value. High-rate dischargeability at the discharge current density of 1200 mA/g first increases from 51.4 % (x = 0) to 57.2 % (x = 0.10), and then decreases to 52.7 % (x = 0.20). The improvement in electrochemical characteristics is ascribed to the secondary phase La₃Ni₁₃B₂, which improves the electrochemical activity of electrode surface, as well as to the phase boundary in multiphase structure, which decreases the lattice distortion and strain energy and enhances the anti-pulverization property of the alloy electrodes.