La_(0.8)Mg_(0.2)(Ni_(2.7)Co_(0.6)Al_(0.1)Mn_(0.1))_x贮氢合金的电化学性能分析  

Electrochemical Performance Study of the La_(0.8)Mg_(0.2)(Ni_(2.7)Co_(0.6)Al_(0.1)Mn_(0.1))_x Hydrogen Storage Alloy

作　　者：李琳[1] 范燕平[2] 刘宝忠[3] 刘宝林[1] 

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]河南理工大学物理化学学院,河南焦作454000 [3]河南理工大学材料科学与工程学院,河南焦作454000

出　　处：《稀土》2012年第3期45-49,共5页Chinese Rare Earths

基　　金：国家自然科学基金资助(50776060);上海市重点学科建设项目资助(S30503)

摘　　要：采用恒电位法、EIS分析及双电极系统对La0.8Mg0.2(Ni2.7Co0.6Al0.1Mn0.1)x(x=0.9～1.10)系列合金进行电化学性能分析。结果表明,x=1.05的合金具有较好的自放电性能(CR=97.3%),而x=1.10的合金有较高的电化学容量(369 mAh.g-1)。合金电极的电化学阻抗谱(EIS)表明,随着化学计量比x的增大,合金电极的电荷迁移电阻先减小后增大,动力学性能先增强后减弱。线性极化测试表明,随着化学计量比x的增大,合金电极表面的电化学反应速率先增大后减小。通过合金电极阳极电流对时间响应的半对数曲线计算的氢扩散系数D随着化学计量比x的增大先增大后降低,说明合金内部的氢扩散能力先增强后降低。In this paper,the electrochemical performances of La0.8Mg0.2（Ni2.7Co0.6Al0.1Mn0.1）x（x = 0.90-1.10） hydrogen storage alloys were studied by constant potential method,EIS analysis and two-electrode system.The results show that,the alloy electrode for x = 1.05 exhibits good charge retention（CR =97.3%）,and the alloy electrode for x = 1.10 shows maximum discharge capacities（369 mAh·g-1）.Meanwhile,the results of the electrochemical impedance spectroscopy,linear polarization,anode polarization,and hydrogen diffusion coefficient measurements all indicate that the exchange current density Io,the limiting current density IL and the hydrogen diffusion coefficient D of the alloy electrodes also increase first and then reduce with the increasing of stoichiometric ratio x in alloys,which signifies that appropriate stoichiometric ratio x is favorable to improve the electrochemical kinetic property of the La0.8Mg0.2（Ni2.7Co0.6Al0.1Mn0.1）x（x = 0.90,0.95,1.00,1.05,1.10） hydrogen storage alloys.

关 键 词：稀土系贮氢合金 AB5型 电化学性能 动力学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TG146.4[金属学及工艺—合金]