稀土Ce对无Co过计量比CaCu_5型合金贮氢和电化学性能的影响  

Influence of rare-earth Ce on performances of hydrogen storage and electrochemistry of cobalt-free over-stoichiometric CaCu_5-type alloys

作　　者：罗永春[1] 刘刚[1] 康龙[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料重点实验室,甘肃兰州730050

出　　处：《兰州理工大学学报》2009年第5期17-22,共6页Journal of Lanzhou University of Technology

基　　金：甘肃省科技攻关项目(SZ001-A52-05)

摘　　要：采用单辊甩带快速凝固方法制备过化学计量比稀土贮氢合金La1-xCexNi4.17Mn0.93Al0.1Fe0.4（AB5.6型,x=0~0.5）,研究Ce元素部分替代La后对合金微观结构、储氢及电化学性能的影响.XRD分析及储氢性能测试结果表明,快淬过化学计量比合金的相组织均为过饱和CaCu5型结构单相,合金晶胞体积与Ce质量分数基本呈线性关系,其中合金的储氢量随Ce质量分数的增加而减小,而吸放氢平台压力增高.电化学测试和分析结果表明,随Ce质量分数的增加,合金电极的活化性能和放电容量有所降低,但电极循环寿命得到明显提高.当x=0、0.5时,合金电极的最大放电容量为328.9、305.4 mAh/g;当x≥0.3时,经100次循环后,合金电极容量保持率S100由x=0时的80%提高至93%~96%;合金电极的高倍率放电性能（HRD）随Ce质量分数的增加呈先减小后增加的趋势.The over-stoichiometric rare-earth hydrogen storage alloys La1-xCexNi4.17Mn0.93Al0.1Fe0.4（AB5.6-type,x=0~0.5） were prepared with rapid solidification method of single-roller and swing belt. The effects of replacing element La with Ce on the microstructures, hydrogen storage, and electrochemical properties of the alloys were investigated. X-ray diffraction （XRD） analysis and hydrogen storage performance test showed that the phase structures of these quick-quenched alloys were all composed of CaCu5-type single-phase ones, the alloy cell volume decreased linearly with the increase of Ce content, the hydrogen absorption capacity of the alloys reduced and platform pressure increased. Electrochemical testing and a- nalysis results showed that with the increase of Ce, the activation performance and discharge capacity of the alloy electrodes decreased, the electrode life period, however, improved significantly. For the alloys with x=0 and x-=0. 5, the largest discharge capacity reached 328. 9 and 305.4 mAh/g respectively. For alloys with x≥0. 3, after 100 charge/discharge cycles, the retentions rates of discharge capacity （S100） raised from 80M （x=0） to 92%-96%. High-rate dischargeability （HRD） of the alloy electrodes showed a trend of declining first when x〈0. 3, and rising when x≥0.3.

关 键 词：AB5型无Co贮氢合金 Ce质量分数 相结构 电化学性能 

分 类 号：TG146.4[一般工业技术—材料科学与工程]