Enhanced electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode material co-coated by graphene/TiO2

The electrochemical performances of LiNi0.5Co0.2Mn0.3O2 (NCM523) layered cathode material, such as poor rate capacity and cycling stability caused by undesirable intrinsic conductivity and low rate of lithium ion transportation, are not fairly good especially at elevated rate and cut-off voltage. To improve these properties, in this study, the co-coating layer of graphene and TiO2 was constructed on NCM523 surface. The graphene/TiO2 coating layer could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration. The enhancement of cycle performance and rate capacity was contributed to the uniform co-modified surface, interacting each other and thus exhibiting synergistic effects. A co-coating layer of graphene/TiO2 is constructed on LiNi0.5Co0.2Mn0.3O2 surface, which could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration. [Display omitted] 1.A graphene/TiO2 coating layer is coated on LiNi0.5Co0.2Mn0.3O2 surface.2.The graphene/TiO2 coating layer much improves the rate capability and cycling stability, decreases the charge transfer resistance and electrochemistry polarization.3.The graphene/TiO2 coating layer could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration.