Silicon/Graphite/Polyaniline Nanocomposite with Improved Lithium-Storage Capacity and Cyclability as Anode Materials for Lithium-ion Batteries

Abstract

A silicon/graphite/polyaniline (Si/G/PANI) nanocomposite is facilely prepared by the in-situ chemical polymerization of aniline monomer in the presence of nano-Si and graphite powders. This composite are examined by scanning electronic microscopy, transmission electronic microscopy, Raman spectroscopy, Fourier-transform infrared spectroscopy, and electrochemical measurements. It is observed that the composite consists of nanosized silicon and graphite distributed uniformly in a polyaniline matrix. Galvanostatic charge-discharge profiles and cycling curves reveal that the Si/G/PANI composite exhibits good electrochemical performance: a high reversible specific capacity of 1392 mAh g-1 for the first cycle and a stable capacity retention with 866 mAh g-1 after 95 cycles. In contrast, pure Si nanoparticles only deliver the reversible capacity of 888 mAh g-1 and 425 mAh g-1 for the first and the 95th cycles, respectively. The enhanced electrochemical performance is mainly attributed to the reinforced electric contact of active materials, better dispersion of Si nanoparticles, and good structural stability of the Si/G/PANI composite electrode during the charge-discharge process, which originate largely from the presence of PANI.