正极材料钴酸锂中钴含量的测定

Determination of Cobalt in Cathode Material of Lithium-cobalt Oxide

用高氯酸溶解LiCoO2试样，用抗坏血酸为掩蔽剂，加入六次甲基四胺缓冲溶液，在pH=6．5的酸性条件下，用孔雀石绿和二甲酚橙作为指示剂，采用乙二胺四乙酸（EDTA）络合滴定容量法，使EDTA与Co^2＋形成稳定的络合物，测定锂离子蓄电池正极材料钴酸锂中的钴含量。讨论了酸溶剂、温度、共存离子等对测定结果的影响。结果表明该方法操作简单，终点容易判断。该方法的相对标准偏差小于0．1％，回收率在99．5％～100．5％之间。

Cobalt in cathode material of lithium-cobah for lithium-ion battery was determined using EDTA volumetry under the condition of pH 6.5 which a steady complex formed between EDTA and cobalt ion. In this method, the per- chloric acid was used to dissolve the sample directly, ascorbic acid was used as masking agents, malachite green and xylenol orange were used as indicator and methenamine buffer solution was taken as pH adjusting agent of the solu- tion. The influence factors of acid, temperature and coexistence ions on the results were discussed. The experiment re- sults indicated that its operation is simple and equivalent point is easily judged for this method. Its relative standard deviation is less than 0. 1% and its recycling rate of cobalt content is from 99.5% to 100. 5%.