Highly enhancement of the SiOx nanocomposite through Ti-doping and carbon-coating for high-performance Li-ion battery

Lithium-ion batteries (LIBs) with SiOx anodes possess high energy density, stemming from the Li-Si alloying reaction. However, several issues hinder the application of SiOx anodes in commercialized LIBs. In particular, the low electronic conductivity and sluggish kinetics of SiOx result in inadequate electrochemical performance. Herein, we report the use of a selective alcoholysis-based reaction to prepare a (C-TixSi1-xOy)@C composite using SiCl4, TiCl4, and ethylene glycol (EG) with benzene. The preferential reaction between EG and TiCl4 results in Ti3+ doping as well as the formation of a homogenous distribution of Ti ions. During the selective alcoholysis reaction, the Ti-Si-O-C-H sol transforms into a (C-TixSi1-xOy)@C composite and benzene decomposes into conductive carbon matrices through dispersion forces. The combination of Ti doping and carbon coating greatly enhance the conductivity of SiOx; in addition, the incorporated carbon acts as an effective oxide buffer, preventing structural degradation. Thus, the (C-TixSi1-xOy)@C composite exhibits a high Li-ion diffusion coefficient and low charge-transfer resistance, resulting in excellent capacity retention of 88.9% over 600 cycles at a high current density of 1 A g(-1) with a high coulombic efficiency of similar to 99%.