▎ 摘　　要

The electrochemical properties of LiNi0.6Co0.2Mn0.2O2, such as cycling stability, rate capacity and coulomb efficiency, are not fairly well at large rate, high cutoff voltage and elevated temperature. In this article, a uniform nanoscale graphene@TiO2 coating layer is skillfully formed on the surface of LiNi0.6Co0.2Mn0.2O2 via an artful sol-gel-based method. The rGO@TiO2 layer is evidenced by a series of detections, and the structures of the pristine and coated materials are investigated in detail. It indicates that the graphene@TiO2 layer with a thickness of similar to 2 nm is uniformly covered on the LiNi0.6Co0.2Mn0.2O2 particles. The "synergistic effects" of graphene@TiO2 composite plays an important role in improving the comprehensive electrochemical performances of the cathode material. Compared with the pristine material, the graphene@TiO2 co-modified LiNi0.6Co0.2Mn0.2O2 shows enhanced electrochemical performances at large rate, elevated temperature, and high cutoff voltage. Particularly, it displays capacity retentions of 93.7% and 89.2% after 150 cycles at 1 C and 2 C, respectively, over 3.0-4.5 V. Even at high temperature of 55 degrees C and upper operating voltage of 4.5 V, the capacity retention of graphene@TiO2-coated sample increases almost 50% compared with the pristine sample after 150 cycles. (C) 2018 Elsevier Ltd. All rights reserved.