Nano-sized tin oxide-modified graphite composite as efficient anode material for lithium ion batteries

Abstract

Nano-sized tin based compounds dispersed graphite composites, synthesized by the electroless plating process and pyrolysis method, act as efficient anode materials for lithium ion batteries (LIBs). The nano-sized tin complexes on the graphite surface can be obtained through a simple chemical reaction between Sn(BF4)2 and Na2S2O4 in aqueous solution and completely converted to SnO2 after pyrolysis. The synthesized tin-modified graphite composites were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM). The electrochemical performance of the composites for application as anode materials in lithium-ion batteries was investigated. The average particle size of nano-SnO2 is ~14.7 nm, as determined by HRTEM. Results of infrared spectra and electrochemical properties indicate that such an optimized nano Sn-based compound on graphite influences the formation of the thin solid electrolyte interface (SEI) in the electrode and thus improves the cycling performance, with high efficiency of 97.3% in LIBs. Nyquist plots show that during Li+ intercalation, the thin SEI film and the low charge transfer resistance of SnO2-modified graphite composite anode plays important roles in improving the electrochemical properties of LIBs.