Studies of LiNi0.6Co0.4O2 cathode material prepared by the citric acid-assisted sol-gel method for lithium batteries

The layered LiNi0.6Co0.4O2 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 degrees C and microcrystalline powders were grown by thermal treatment at 700 degrees 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 LiNi0.6Co0.4O2 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 LiNi0.6Co0.4O2 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 LiNi0.6Co0.4O2 is discussed in relation with its synthesis procedure.