Enhanced electrochemical performance of Li3V1.5Al0.5(PO4)3-modified Li1.12(Ni0.18Co0.07Mn0.57)O2 cathode for Li-ion batteries

Abstract

Li-rich manganese-based cathode materials are very promising for rechargeable Li-ion batteries. In our task, the Li-rich layered oxides Li1.12(Ni0.18Co0.07Mn0.57)O2 (LLMO) are prepared via the method of co-precipitation and solid-state reaction. Li3V1.5Al0.5(PO4)3 (LVAP) is applied to modify the LLMO by the chemical deposition method. Successful coating of LVAP layer on the pristine LLMO surface is demonstrated by TEM and XPS. Notably, the initial coulombic efficiency of LVAP-modified LLMO is 93%, which is improved compared to 82% of the pristine LLMO. The modified electrode also achieves excellent cyclic stability, which retains 96% of capacity after 100 cycles while the pristine electrode only retains 75%. Moreover, in comparison to the 100 mAh g−1 capacity of pristine LLMO at 5C, the LVAP-modified LLMO provides a high discharge capacity of 176 mAh g−1. In conclusion, this paper has demonstrated that the surface modification with LVAP is dedicated to improving the cyclic performance and rate capability of Li-rich layered oxides.