(1. 中国科学院 金属研究所, 沈阳 110015;
2. 东北大学 材料与冶金学院, 沈阳 110006;
3. 国家高技术新型储能材料工程开发中心, 中山 528437;
4. 长沙矿冶研究院, 长沙 410012)
摘 要: 研究了熔体旋淬和常规熔铸Ml(NiCoMnAl)5贮氢合金的微结构和电化学行为 SEM和XRD分析表明,熔体旋淬合金由细小的柱状晶组成,它们的晶体结构与铸态一样, 都为CaCu5型六方晶体结构。电化学测试表明,旋淬态合金电极初始容量较高(>210 mA·h/g),经1~2次循环就可达到最大放电容量。旋淬速度为10 m/s的合金电极的放电容量(294 ]mA·h/g)稍高于铸态合金电极的容量,所有旋淬态合金电极充放电循环稳定性皆优于铸态合金。在600 mA/g电流质量密度下,旋淬速度为10 m/s的合金电极具有较好的高倍率充放电能力,但随着循环次数的增加,其容量稳定性稍次于旋淬速度为25 m/s和40 m/s的合金电极。
关键字: 熔体旋淬; 贮氢合金电极; 电化学行为;柱晶组织
melt-spinning alloy Ml(NiCoMnAl)5
(1. Institute of Metal Research, The Chinese Academy of Sciences,
Shenyang 110015, P.R.China;
2. School of Materials and Metallurgy, Northeastern University,
Shenyang 110006, P.R.China;
3. National Engineering Development Center of HighTech EnergyStorage Materials,
Zhongshan 528437, P.R.China;
4. Changsha Institute of Mining and Metallurgy, Changsha 410012, P.R.China)
Abstract:The microstructure and electrochemical behaviors of Ml(NiCoMnAl)5 alloys prepared by both the melt-spinning method and the conventional induction melting were investigated. SEM and XRD analysis show that melt-spinning alloys are of columnar microstructure which belong to the CaCu5 type hexagonal crystal structure as same as as-cast alloy. The electrochemical measurements show that the initial capacities of melt-spinning alloy electrodes are all above 210 mA·h/g, reaching their maximum capacities after the second charge-discharge cycles. The maximum capacity (294 mA·h/g) of melt spinning (10 m/s) alloy electrodes is the same as that of as-cast alloy electrode, the stability of charge-discharge cycles of all meltspinning alloy electrodes is better than that of the as-cast alloy electrodes. When charged at 600 mA/g, the melt spinning (10 m/s) alloy electrode has better high rate discharge capability; but with the cycle number increasing, the cycle stability is less than those electrodes of melt spinning rate of 25 m/s and 40 m/s.
Key words: melt spinning; hydrogen storage alloy electrode; electrochemical behaviors; columnar structure