Studies of LiNi0.6Co0.4O2 Cathode Material Prepared by the Citric Acid-Assisted Sol-Gel Method for Lithium Batteries

The layered LiNi_0.6Co_0.4O₂ powders were synthesized at low temperature by a sol-gel method using citric acid as a chelating agent. Submicron-sized particles of the precursor were obtained at temperature below 400°C and microcrystalline powders were grown by thermal treatment at 700°C for 4 h in air. The carboxylic-based acid acted such as a fuel, decomposed the homogeneous precipitate of metal complexes at low temperature, and yielded the free impurity LiNi_0.6Co_0.4O₂ single-phase suitable for electrochemical application. The synthesized products have been characterized by structural (XRD, SEM), spectroscopic (FTIR, Raman) and thermal (DTA/TG) analyses. Raman and FTIR measurements provide information on the local environment of the cationic sublattice of LiNi_0.6Co_0.4O₂ solid solution. Electrochemical performance of the synthesized products in rechargeable Li cells were evaluated by employing as cathodes in non-aqueous organic electrolyte mixture of 1M LiPF₆ in EC + DMC. The electrochemical behaviour of synthesized LiNi_0.6Co_0.4O₂ is discussed in relation with its synthesis procedure.