Silicon nanoparticles are coated with the conductive polyaniline (PANI) using in situ polymerization method as anode materials to improve the electrochemical performance for lithium ion batteries. At first, the physicochemical and electrochemical properties of the doped polyaniline in the lithium ion electrolyte are investigated. After that, the effect of different contents of PANI for preparing Si/PANI composites on the composition and structure and thus the electrochemical performance are investigated. The structure and morphology of asprepared materials are characterized systematically by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). It is demonstrated that the silicon/polyaniline composite presents the core/shell structure. The Si/PANI composite with 12.3 wt% PANI exhibits the optimum electrochemical performance. The electrode still maintains better reversible capacity of 766.6 mAh g −1 , and the capacity retention of 72 % is retained after 50 cycles at current density of 2 A g −1 . The good electrochemical properties can be attributed to the PANI-coating layer, which can improve the electrical conductivity of the Si-based anode materials for lithium ion batteries and accommodate the volume change of silicon during the charge-discharge processes.

Silicon anode of lithium ion batteries was fabricated with different binders and conductive additives (acetylene black, SuperP, VulcanXC-72, BP2000), and the electrochemical performance was investigated in detail. The effect of morphology and addition amount of conductive additives on the electrochemical performance of silicon electrode were investigated. Then, the appropriate type and content of binder in the silicon electrode was optimized. The morphology of silicon electrodes were characterized by scanning electron microscope(SEM). Electrochemical performances of the silicon electrodes were measured by constant current charge-discharge and cyclic voltammetry(CV). The results shows that SuperP has good electrical conductivity, a suitable surface area of 75.8 m 2 /g and average particle size of 39.24 nm, which can improve cycling performance and rate performance of the silicon electrode. With 15wt% SuperP and 15wt% CMC, the electrode exhibits a reversible capacity of 1143.8 mAh/g after 50 cycles.