Co部分替代Ni对La_(0.4)Er_(0.4)Mg_(0.2)Ni_(3.3-x)Co_xAl_(0.2)(0.1≤x≤0.4)储氢合金结构和电化学性能的影响  

Effect of Co substitution for Ni on the structure and electrochemical properties of La_(0.4)Er_(0.4)Mg_(0.2)Ni_(3.3-x)Co_xAl_(0.2)(0.1≤x≤0.4)hydrogen storage alloys

作　　者：李斯[1] 邓健秋[1] 唐莹[1] 刘鹏[1] 

机构地区：[1]桂林电子科技大学材料科学与工程学院,广西桂林541004

出　　处：《桂林电子科技大学学报》2014年第3期254-258,共5页Journal of Guilin University of Electronic Technology

基　　金：国家自然科学基金(51261003);广西自然科学基金(2012GXNSFGA060002;2011GXNSFD018004);广西教育厅科研项目(201201ZD009);广西信息科学实验中心项目(20130113)

摘　　要：为了改善储氢合金La0.4Er0.4Mg0.2Ni3.3-xCoxAl0.2(0.1≤x≤0.4)的结构和综合电化学性能,采用Co部分替代Ni的方法,实验采用高频感应炉制备La0.4Er0.4Mg0.2Ni3.3-xCoxAl0.2(0.1≤x≤0.4)储氢合金。通过X射线衍射技术和电化学测量方法研究储氢合金的晶体结构和电化学性能。XRD图谱显示样品储氢合金主要由LaNi5和La2Ni7相组成,电化学实验表明,随着Co含量的增高,储氢合金电极的最大放电容量和50次循环后的容量保持率S50基本呈现增加状态,放电容量从x=0.1时的225mA·h/g升高到x=0.4时的254.9mA·h/g,容量保持率S50从57.11%(x=0.1)增加到66.10%(x=0.4),但高倍率性能不断下降。通过交流阻抗(EIS)和线性扫描(LS)对Co替代Ni的合金动力学性能分析发现,Co替代Ni后合金的表面电荷转移能力先降低后升高。The method of Co to partial substitution Ni is used to improve the structure and electrochemical properties of the hydrogen storage La0.4 Er0.4 Mg0.2 Ni3.3-xCoxAl0.2 （0.1≤x≤0.4）,La0.4 Er0.4 Mg0.2 Ni3.3-xCoxAl0.2 （0.1≤x≤0.4）alloys are prepared by induc-tion melting.The structure and electrochemical properties of La0.4 Er0.4 Mg0.2 Ni3.3-xCoxAl0.2 （0.1≤x≤0.4）hydrogen storage al-loys have been investigated by X-ray diffraction （XRD）technique and electrochemical measurement methods.XRD results reveal that all the alloys mainly consist of LaNi5 phase and La2 Ni7 phase.The electrochemical experiments demonstrate that the substitution of Co for Ni can increase the maximum discharge capacity and discharge capacity retention after 50 charge-discharge cycle and decrease the high rate dischargeability of the alloy electrodes.With x increasing from 0.1 to 0.4,the discharge capacity increases from 225 mA·h/g to 254.9 mA·h/g and the discharge capacity retention increases from 57.11% to 66.10% after 50 charge-discharge cycle.The results obtained from the electrochemical impedance spectroscopy （EIS）show the charge-transfer ability on the alloys surface decreases firstly and then increases with the Co addition.

关 键 词：储氢合金 电化学性能 高倍率性能 电化学阻抗图谱 

分 类 号：TB31[一般工业技术—材料科学与工程]