摘要
采用化学沉淀法制备的高电化学性能的球形Ni(OH)2,通常需要加入氨水作配合剂,但制备完成后会产生大量含氨的废液。通过对母液循环利用的研究,实现了含有Ni(OH)2晶种的部分母液的循环使用。采用SEM、充放电测试、循环性能测试等手段分析了晶种含量、母液循环量对镍电极性能的影响。结果表明,含有晶种的母液比不含晶种的母液制得的Ni(OH)2晶体表面更光滑,球形度更好;晶种的含量取在6～9g/L反应8h时,制备的Ni(OH)2晶体振实密度大于1.90g/cm3,粒径在10μm左右,放电容量达200mA·h/g;母液的循环量不超过20%,Ni(OH)2产品中SO42-的含量低于0.3%;在晶种含量为9g/L,母液的循环量为20%,反应10h条件下得到的球形Ni(OH)2产品放电容量为215.06mA·h/g,1.2V以上的放电容量达到153.33mA.h/g,占总放电容量的71.3%,明显高于同条件下不含晶种的产品性能,不仅减少了含氨废液的排放量和废液的处理量,而且有利于提高Ni(OH)2的振实密度和球形度,并可有效缩短制备反应的时间。
Ammonia is usually added as a complex agent in preparation of high electrochemical and spherical nickel hydroxide by chemical precipitation. As the result, a lot of liquid waste with ammonia has to be disposed. Studies show that part of the mother liquor with crystal seeds can be reused in the preparation. SEM, charge-discharge, and cycle life test were used to analyze the influence on nickel electrode of the content of crystal seeds and the quantity of mother liquid. Studies showed that the mother liquid with crystal seeds was much better than the one without crystal seeds in the field of surface and sphericity. When mother liquor with 6 - 9 g/L crystal seeds reacting for about 8 hours, the tap density of the nickel hydroxide can reached 1.90 g/cm^3, the diameter of 10 μm and the discharge capacity of 200 mA · h/g. When the cycle content of mother liquid was less than 20% , the content of SO4^2- could be less than 0.3%. Using 20% mother liquor with 6 -9 g/L crystal seeds to react for about l0 hours, the discharge capacity of nickel electrode reached 215.06 mA · h/g. The discharge capacity of nickel electrode above 1.2 V is 153.33 mA · h/g, accounting for 71.3% of the discharge capacity. It not only improves the discharge capacity and reduces the dispose quantity of liquid waste with ammonia, but also improves the tap density and the spheroid degrees of nickel hydroxide. It also shortens the reaction time effectively.
出处
《应用化学》
CAS
CSCD
北大核心
2007年第9期1009-1012,共4页
Chinese Journal of Applied Chemistry
基金
河北省自然科学基金资助项目(200006)
