( 1. 中南大学 化学化工学院, 长沙 410083;
2. 中南大学 粉末冶金研究院, 长沙 410083)
摘 要: 采用粉末烧结法， 制备了一系列掺杂Li的AB5型稀土贮氢合金， 并研究了Li掺杂量对贮氢合金MlNi3.55Mn0.40Al0.30Co0.70Lix相结构和电化学性能影响。 结果表明： 随Li掺杂量的增加， 合金的晶胞参数c、 c/a和晶胞体积V也随之增大； 适量Li(x≤0.20)掺杂对合金的电化学容量有所提高， MlNi3.55Mn0.40Al0.30Co0.70Li0.20合金的0.2C放电容量达到273.53mA·h/g； 掺杂Li能改善合金的高倍率放电性能， 当Li的含量为0.20～0.30时， 合金的高倍率放电性能最好； 掺杂Li能不同程度地提高贮氢合金的充放电循环稳定性， 当x=0.20时， 其循环性能最好， MlNi3.55Mn0.40Al0.30Co0.70Li0.20合金200次循环的电容与最大电容的比率(S200)达86.2%, 但当Li掺杂量大于0.50时， 合金的循环性能反而下降。
关键字: 贮氢合金； Li掺杂； 粉末烧结； 电化学性能； 相结构
（ 1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. Powder Metallurgy Research Insitute, Central South University,
Changsha 410083, China）
Abstract: A series of AB5 rare earth-based hydrogen storage alloy with Li doping were prepared by powder-sintering, the effects of Li doping on the phase structures and electrochemical properties of MlNi3.55Mn0.40Al0.30Co0.70Lix hydrogen storage alloy were investigated. The results show that the crystal lattice parameters (c, c/a) and crystal lattice volume (V) enlarge with the increase amount of Li doping. The discharge capabilities of the alloy is improved with minor amounts of Li doping(x≤0.2), 0.2C discharge capabilities of MlNi3.55Mn0.40Al0.30Co0.70Li0.20 is 273.53mA·h/g. The high rate capability of the alloy is improved with Li doping. When x is 0.2-0.3, maximate high-rate discharging capability of the alloy can be obtained. The cycling life of the alloy is improved with the increase of Li doping, the rate of capacity after 200 cycles to Cmax of MlNi3.55Mn0.40Al0.30Co0.70Li0.20 is 86.2%, but the cycling properties reduce when amounts of Li doping is more than 0.50.
Key words: hydrogen storage alloy; Li doping; powder-sintering; electrochemical properties; phase structure
