Enhanced overcharge behavior and thermal stability of commercial LiCoO2 by coating with a novel material

Commercial LiCoO₂ has been modified with MnSiO₄ as a novel coating material. The structures, morphologies, overcharge behaviors and thermal stabilities of the pristine and MnSiO₄-coated LiCoO₂ materials were studied. The MnSiO₄-coated LiCoO₂ had initial discharge specific capacities of 181.1 and 232.2 mAh g⁻¹ within the potential ranges 2.75–4.5 and 2.75–4.7 V (vs. Li⁺/Li), respectively. It was found that the overcharge tolerance of the coated cathode was significantly better than that of the pristine LiCoO₂ under the same conditions – the discharge specific capacities of the coated cathode at upper charge cutoff voltages of 4.5 and 4.7 V were as high as 168.7 and 154.3 mAh g⁻¹, respectively, after 50 cycles. Moreover, DSC showed that the coated LiCoO₂ had a higher thermal stability than the pristine LiCoO₂.