Design of SiO/TiO@C hierarchical structure for efficient lithium storage.

The large volume expansion effect and unstable solid electrolyte interface films of SiO-based anode materials have hindered their commercial development. It has been shown that composite doping is a general strategy to solve critical problems. In this study, TiO-doped core-shell SiOTiO@C composites were created using the sol-gel method. On the one hand, the uniformly dispersed TiOnanoparticles can alleviate the volume expansion of the SiOactive material during the lithiation process. On the other hand, they can react with Lito form LiTiO, thereby increasing the ion diffusion rate in the composite material. The outer carbon shell acts as a protective layer that not only alleviates the volume expansion of the composite, but also improve the electron migration rate of the composite. The prepared SiO/TiO@C composite has a reversible capacity of 828.2 mA h g(0.2 A g100 cycles). After 500 cycles, it still maintains a reversible capacity of 500 mA h geven at a high current density of 2 A g. These findings suggest that SiO/TiO@C composites have a bright future in applications.