Investigation on the Mechanism of the Pechini Process for LiCoO_2

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 HCit2-. During the process of complexation, complex compound is generated by Co2+ and HCit2-, 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.