Controllable synthesis of carbon-coated Sn⿿SnO 2 ⿿carbon-nanofiber membrane as advanced binder-free anode for lithium-ion batteries

A carbon-coated composite consisting of Sn, SnO2, and porous carbon-nanofiber membrane (Sn⿿SnO2⿿CNF@C) was successfully prepared via electrospinning followed by carbonization and low-temperature hydrothermal treatment. The thickness of the carbon overlayer formed by using sucrose as the carbon source could be well controlled by adjusting the sucrose concentration. The three-dimensional (3D) nanofiber network structure allowed the Sn⿿SnO2⿿CNF@C membrane to be used directly as an anode in lithium-ion batteries without adding any polymer binders or electrical conductors. The composite electrodes of this material exhibited a high discharge capacity of 712.2 mA h g⿿1 at a high current density of 0.8 A g⿿1 after 200 cycles, as well as good cycling stability and excellent rate capability, which can be ascribed to the improved electrochemical properties of the Sn⿿SnO2 particles provided by the protective carbon coating and the 3D carbon nanofiber membrane. The composite can thus be widely used as an advanced binder-free anode material in high-current rechargeable lithium-ion batteries and extended to the fabrication of flexible electrodes.