低钴LaNi_(4.5)Co_(0.4-x)Al_(0.1+x)储氢合金的相结构和电极性能  

Phase Structure and Electrode Performance of Low-Co LaNi_(4.5)Co_(0.4-x)Al_(0.1+x) Hydrogen Storage Alloys

作　　者：申玉求[1] 周怀营[1,2] 姚青荣[1,2] 王仲民[1] 钟燕[1,2] 

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 [2]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中国稀土学报》2012年第5期581-586,共6页Journal of the Chinese Society of Rare Earths

基　　金：国家自然基金(50971049;50961004);广西自然基金(2011GXNSF18004)资助

摘　　要：采用XRD,SEM等材料分析方法及恒电流充放电、线性极化等电化学测试技术研究了低钴LaNi4.5Co0.4-xAl0.1+x(x=0.00～0.30)储氢合金的电极性能。XRD分析表明:合金均为单一CaCu5型六方结构的LaNi5相结构,随着合金中Al含量的增加,其晶胞参数a和c及晶胞体积都显著增加。301 K时模拟电池测试结果表明:x=0.00时,合金电极具有最佳自放电性能;x=0.15时,合金电极的循环稳定性能最好,其高倍率放电性能达到70.21%(放电电流密度为1800 mA.g-1)。当0.10≤x≤0.15时,Al替代Co能改善AB5型低钴储氢合金的循环稳定性能和高倍率放电性能。By means of XRD, SEM analyses, and electrochemical methods including the galvanostatic charge-discharge and linear polarization etc, a series of experiments were performed to study the electrode per- formance of low-Co LaNi4.5 Co0.4-xAl0. 1＋x （x = 0.00 0. 30） hydrogen storage alloys. The results of XRD analysis indicated that as-prepared samples were sin- gle-phase alloys, with a hexagonal CaCu5 structure （LaNi5 phase）. An apparent increase of lattice pa- rameters （a, c and V） were observed with the in- crease of Al doping content （x）. A simulation battery test at 301 K were employed to investigate their electrode properties, the results proved that the alloy electrode had better self-discharge properties when x = 0.00, and a good cycle stability and high-rate dis- charge capacity were observed when x = 0.15, where the high-rate discharge efficiency of 70.21% were ob- tained in the discharge current of 1800 mA·g-1. When 0.10≤x≤0.15, cycle life and high-rate dis- chargeability of low-Co AB5-type hydrogen storage al- loys could be improved by the substitution of Co with Al.

关 键 词：低钴储氢合金 相结构 电极性能 高倍率放电 稀土 

分 类 号：TG139.7[一般工业技术—材料科学与工程]