Pechini法制备LiCoO_2机理的研究

Investigation on the Mechanism of the Pechini Process for LiCoO_2

以硝酸钴和氢氧化锂为原料,柠檬酸为络合剂,乙二醇为交联剂,用Pechini法制备了LiCoO2粉体,研究了反应体系的最佳pH值,用红外光谱研究了络合和酯化这两个关键步骤.结果表明pH=5时,溶液中柠檬酸主要以HCit2-离子的形式存在.在络合过程中,Co2+ 和HCit2-生成络合物,而Li+均匀分散在柠檬酸溶液中.在酯化聚合过程中,乙二醇将不同的络合物分子聚合到一起,脱水而形成具有空间结构的凝胶.

LiCoO2 powders were prepared by the Pechini method with cobalt nitrate and lithium hydrate as raw materials, citric acid as complexing agent and ethylene alcohol as cross-linking agent. The optimal pH for the Pechini process was studied. Two key steps, complexation and esterification, were explored with infrared spectra. The results show that in the solution of pH=5, citric acid exists mostly in the form of HCit(2-). During the process of complexation, complex compound is generated by Co2+ and HCit(2-), while Li+ is homogenously dispersed in the citric acid solution. During the process of fat polymerization, different complexed molecules are polymerized together by ethylene alcohol. After dehydration, gels with space structure are formed.