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

• LiNbO3-coated LiCoO2 materials are synthesized by a sol-gel method.
• New phases are grown on LiNbO3 coated LiCoO2 cathode material.
• New coating layer has an effective improvement of the 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. 2 mol%–800 °C-coated sample has a discharge capacity of 175.2 mAh/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.

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