One-step synthesis of a double conductive layer C-SiO_x-TiO_2 co-coated Li_4Ti_5O_(12) anode material toward a high-rate and large-capacity lithium-ion battery

摘要

The preparation of lithium titanate electrode materials with a high energy density and high rate performance is of great significance to its commercialization. In this work, we report a simple strategy to prepare a double conductive layer C-SiOx-TiO2 co-coated Li4Ti5O12(CS-TiO2/LTO) anode material by the sol?gel method to achieve more efficient lithium-ion storage. During a heat treatment process, anatase titanium dioxide was formed by the reaction between the lithium titanate surface and SiO2 layer. The SiO2 and polydopamine layers underwent a carbothermal process to form a SiOx layer. The composite material made full use of the advantages of the highcapacity SiOx coating layer and the double conductive layer combining anatase titanium dioxide with N-doped C. The C-SiOx-TiO2 co-coated Li4Ti5O12 composite exhibited significantly improving specific capacity, rate capability, and cycling stability compared to commercial Li4Ti5O12. The as-prepared CS-TiO2/LTO had a high tap density and electronic conductivity (8.45 x 10-4 S cm- 1), as well as a high ionic conductivity (4.62 x 10-12 cm2 S- 1), which were responsible for its excellent rate capability (221.7 mAh/g at 20C) and stable long-term cycling performance (0.008% fade per cycle after 1000 cycles at 20C).