Controllable synthesis of carbon-coated Sn–SnO2–carbon-nanofiber membrane as advanced binder-free anode for lithium-ion batteries

•Carbon-coated Sn–SnO2–carbon-nanofiber anodes are introduced.•A modified low-temperature hydrothermal carbon-coating method was used.•The thickness of carbon coating can be well controlled.•Ultra-dispersed Sn–SnO2 and carbon coating led to high capacity and cyclical stability.

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.

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