( 1. 中南大學(xué) 化學(xué)化工學(xué)院, 長沙 410083;
2. 中南大學(xué) 粉末冶金研究院, 長沙 410083)
摘 要: 采用粉末燒結(jié)法， 制備了一系列摻雜Li的AB5型稀土貯氫合金， 并研究了Li摻雜量對貯氫合金MlNi3.55Mn0.40Al0.30Co0.70Lix相結(jié)構(gòu)和電化學(xué)性能影響。 結(jié)果表明： 隨Li摻雜量的增加， 合金的晶胞參數(shù)c、 c/a和晶胞體積V也隨之增大； 適量Li(x≤0.20)摻雜對合金的電化學(xué)容量有所提高， MlNi3.55Mn0.40Al0.30Co0.70Li0.20合金的0.2C放電容量達到273.53mA·h/g； 摻雜Li能改善合金的高倍率放電性能， 當(dāng)Li的含量為0.20～0.30時， 合金的高倍率放電性能最好； 摻雜Li能不同程度地提高貯氫合金的充放電循環(huán)穩(wěn)定性， 當(dāng)x=0.20時， 其循環(huán)性能最好， MlNi3.55Mn0.40Al0.30Co0.70Li0.20合金200次循環(huán)的電容與最大電容的比率(S200)達86.2%, 但當(dāng)Li摻雜量大于0.50時， 合金的循環(huán)性能反而下降。
關(guān)鍵字: 貯氫合金； Li摻雜； 粉末燒結(jié)； 電化學(xué)性能； 相結(jié)構(gòu)
LU Zhou-guang1, HUANG Bai-yun2
（ 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
