Facile fabrication of SnO2@TiO2 core–shell structures as anode materials for lithium-ion batteries

Abstract

A novel strategy to fabricate SnO₂@TiO₂ composite was developed by combining the glucose-mediated hydrothermal method along with a sol–gel step, followed by a sintering process. Herein, glucose was found to play dual roles of facilitating the rapid precipitation of polycrystalline SnO₂ nanocolloids in the hydrothermal process and act as a pore-forming material to leave behind nanopores when it is combusted in the sintering process. Due to the combined superiority of TiO₂ as a inert nanoshell and SnO₂ as a core with a high theoretical specific capacity, together with the combustion-formed carbon-derived voids with many extra free spaces to buffer the volume change, the obtained SnO₂@TiO₂ composite has potential for use as an anode material for lithium-ion batteries with enhanced electrochemical performances. A high reversible capacity of 910 mA h g⁻¹ was maintained over 300 cycles at a current density of 100 mA g⁻¹. Even at a high current density of 1000 mA g⁻¹, the substantial discharge capacity could still reach 617 mA h g⁻¹ after 1000 repeated cycles. Such excellent cycling stability and remarkable rate capability of the designed SnO₂@TiO₂ composite can be attributed to its novel structure and the synergistic effects between the SnO₂ core and TiO₂ shell.