Study of new phases grown on LiNbO₃ coated LiCoO₂ cathode material with an enhanced electrochemical performance

LiNbO₃, a fast ionic conductor, was chosen as the layer to coat commercial LiCoO₂ particles through a sol-gel method followed by heat treatment at various temperatures. As opposed to conventional coating materials, we first report new coating layer resulting from the reaction between coating material LiNbO₃ and bulk material LiCoO₂, is grown during annealing. The composition of formed new coating layer varies with the calcination temperature. Electrochemical properties of the coated material annealed at different temperatures indicated that the formed new coating layer had an effective enhancement of the cycle life, compared to a bare sample. 2mol%-800°C-coated sample has a discharge capacity of 175.2mAh/g after 70 cycles with capacity retention of 97.1%, showing the best cycling stability. It can be speculated that the formed new coating layer of Co₃O₄ and Li₃NbO₄ has an effective improvement of the electrochemical performance.