Hierarchical SnO2 /Carbon Nanofibrous Composite Derived from Cellulose Substance as Anode Material for Lithium-Ion Batteries.

Abstract

A hierarchical fibrous SnO2 /carbon nanocomposite composed of fine SnO2 nanocrystallites immobilized as a thin layer on a carbon nanofiber surface was synthesized employing natural cellulose substance as both scaffold and carbon source. It was achieved by calcination/carbonization of the as-deposited SnO2 -gel/cellulose hybrid in an argon atmosphere. As being employed as an anode material for lithium-ion batteries, the porous structures, small SnO2 crystallite sizes, and the carbon buffering matrix possessed by the nanocomposite facilitate the electrode-electrolyte contact, promote the electron transfer and Li(+) diffusion, and relieve the severe volume change and aggregation of the active particles during the charge/discharge cycles. Hence, the nanocomposite showed high reversible capacity, significant cycling stability, and rate capability that are superior to the nanotubular SnO2 and SnO2 sol-gel powder counter materials. For such a composite with 27.8 wt % SnO2 content and 346.4 m(2) g(-1) specific surface area, a capacity of 623 mAh g(-1) was delivered after 120 cycles at 0.2 C. Further coating of the SnO2 /carbon nanofibers with an additional carbon layer resulted in an improved cycling stability and rate performance.