Core-shell nano-structured carbon composites based on tannic acid for lithium-ion batteries

Core-shell nano-structured carbon composites have been used as electrode materials in lithium-ion batteries (LIBs) with increasing attention. The large volume swing during lithiation/delithiation processes and poor electronic conductivity are two key issues in the newly-proposed electrode materials, which severely limit their practical applications in LIBs. In order to solve these problems, we report a facile and versatile method to prepare core-shell nano-structured carbon composites using low cost and widely available tannic acid as the carbon source. The carbon layers with controlled thicknesses of 6-12 nm and 1-3 nm were coated on the surface of Si and TiO2 nanoparticles, respectively. Due to the carbon layers, both the Si@C and TiO2@C nanocomposites used as anode materials in LIBs showed excellent electrochemical performances including good cycling stability and high rate capability. We believe that this method may be applicable to various carbon-coating nanocomposites.