添加元素对AB_2型Laves相合金电化学性能的影响

Effect of Additive Elements on Electrochemical Properties of AB2-type Laves Phase Alloys

比较系统地研究了 AB2 型 Laves相合金 Zr0 .9Ti0 .1Ni0 .1Mn0 .7V0 .3 M0 .1( M=None,Ni,Mn,V,Co,Cr,Al,Fe,Mo,Si,C,Zn,Cu和 B)的相结构和电化学性能以及高温和低温放电性能等 .结果表明 ,1 4种合金均具有六方 C1 4型 Laves相的主相晶体结构 ,同时 ,含有少量立方 C1 5型 Laves相和一些由 Zr.9Ni11及 Zr Ni组成的非 Laves相 ;添加 V和 Mn可提高 AB2 合金的放电容量 ;添加 B和 Mn则显著提高了 AB2 合金的高倍率放电性能和低温放电容量 ;添加 Al,C,Si和 Co对合金电极的循环稳定性改善明显 ;而 Mn,Ni,V,Fe,Cu,Mo和 B等却不同程度地降低了循环稳定性 ;添加 Si,Mo,V,Cr和 Al可明显改善合金电极的自放电性能 ;添加 Si,Cr,V可显著改善 AB2 合金电极的高温放电性能 .讨论了各种添加元素影响合金性能的可能原因 .

For examining the effect of the additive elements on the AB2-type Laves phase alloys {Zr{0.9}Ti{0.1}Ni{0.1}Mn{0.7}V{0.3}M{0.1}}(M=None, Ni, Mn, V, Co, Cr, Al, Fe, Mo, Si, C, Zn, Cu and B), the phase structure, the electrochemical capacity, high rate dischargeability, charge retention, cycling stability, high-temperature and low-temperature dischargeability of the alloys have been investigated. The XRD results show that all alloys consist of a large amount of the hexagonal C14 Laves phase {along} with a small level of the cubic C15 Laves phase and some non-Laves phases. The addition of V and Mn increases the discharge capacity of the AB2 alloy electrodes and the high rate capacity, and low-temperature dischargeability is dramatically increased with B and Mn addition, the {Zr{0.9}Ti{0.1}Ni{1.1}Mn{0.7}V{0.3}B{0.1}} exhibited the discharge capacity of 200 mA5h/g at discharge current of {1 320 mA/g}. It is found that a small amount addition of Al, C, Si and Co greatly improved the cycle life, but addition of Mn, V, Ni, Fe, Cu, Mo and B decreased the cycling stability of the AB2 alloy electrodes to some extent, especially addition of Mn resulted in decreasing of cycling stability drastically. The addition of Si, Mo, V, Cr and Al is useful to improving self-discharge characteristics. Considerable improvement in the high-temperature dischargeability was observed by addition of Si, Cr and V, the discharge capacity was up to 210 mA5h/g at 65 ℃ for Zr{0.9}Ti{0.1}Ni{1.1}Mn{0.7}V{0.3}Si{0.1} alloy electrode.