Al含量对AB_5型储氢合金电极低温和高倍率性能的影响（英文）  

Effects of Al Content on Low-Temperature and High-Rate Performance of MmNi_(4.0-x)Co_(0.7)Mn_(0.3)Al_x Alloys

作　　者：汤争耀 周万海[1] 朱丁 吴朝玲[1] 黄利武[1] 刘昆 陈云贵[1] 

机构地区：[1]四川大学材料科学与工程学院,成都610065 [2]四川大学新能源与低碳技术研究院,成都610065

出　　处：《无机化学学报》2017年第10期1881-1888,共8页Chinese Journal of Inorganic Chemistry

基　　金：四川省科技创新苗子工程(No.2017RZ0033)资助项目

摘　　要：系统地研究了Al含量对富Ce储氢合金MmNi_(4-x)Co_(0.7)Mn_(0.3)Al_x(x=0,0.1,0.2,0.3)电极综合电化学性能,尤其是对低温和高倍率性能的影响。在常温下,储氢合金电极放电容量和循环性能均随着Al含量的增加而增加,而高倍率放电性能严重下降。-20℃时,放电容量仍随着Al含量的增加而增加,但在-40℃下放电容量随之严重衰退。电化学动力学结果表明,常温下高Al合金高倍率性能的降低主要是由于电极表面电荷转移过程的恶化;低温-40℃下,Al同时降低了合金电极的表面电催化活性以及体相H扩散能力,严重恶化电极过程动力学,从而导致了高Al合金极低的容量及电压输出。考虑到各电极的综合电化学性能,MmNi_(3.8)Co_(0.7)Mn_(0.3)Al_(0.2)为最佳的成分配比。Effects of Al content on the comprehensive electrochemical performance of Ce-rich MmNi4-xCo0.7Mn0.3Alx （x=0, 0.1, 0.2, 0.3） hydrogen storage alloys, particularly the low-temperature and high-rate capacity have been systematically investigated. At room temperature, both the discharge capacity and cycling stability of the electrode increase with the Al content increases, but the high-rate dischargeability seriously deteriorates. The discharge capacity still increases with the increase of Al content at -20℃, but gradually deteriorates when the temperature drops down to -40℃. Electrochemical kinetics results demonstrate that the high-rate capacity recession of the high-Al alloy at room temperature is contributed to the deterioration of the charge-transfer process. When the temperature drops down to -40℃, Al deteriorates both the surface catalytic ability and the bulk hydrogen diffusion ability, leading to the severe drop of discharge capacity and potential of the high-Al alloy. Based on the comprehensive electrochemical properties of the electrodes, the optimal composition of MmNi4-xCo0.7Mn0.3Alx is obtained when x=0.2.

关 键 词：AB5型储氢合金 低温电化学性能 Al替代 镍氢电池 电化学动力学 

分 类 号：TB331[一般工业技术—材料科学与工程]