Nanoscopically and uniformly distributed SnO2@TiO2/C composite with highly mesoporous structure and bichemical bonds for enhanced lithium ion storage performances

Abstract

The ultralow volume deformation (<4%) and low cost have aroused great interest in using TiO₂ as the anode of lithium ion batteries (LIBs), but its low capacity (168 mA h g⁻¹), no more than half of the theoretical capacity, limits its practical application in high-energy-density LIBs. In order to solve this problem, here we propose a one-step method for fabrication of the SnO₂@TiO₂/C nanocomposite, which features a superior nanoarchitecture with mesopores, interfacial chemical bonds, vast phase boundaries, carbon coating, and ultrasmall nanocrystals. These nanostructures endow SnO₂@TiO₂/C with a high capacity of 830.7 mA h g⁻¹ at 0.5C after 100 cycles, excellent cyclability over 1000 cycles with negligible capacity loss per cycle (0.004%) at 10C, and a high lithium ion transport rate within a few seconds for one cycle. Importantly, the full cell with prelithiated SnO₂@TiO₂/C as the anode and commercial LiCoO₂ as the cathode achieves a high energy density of 328.4 W h kg⁻¹ at 0.1C and 245.9 W h kg⁻¹ at 1C, which are superior to those of previously reported TiO₂-based materials.