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Si-C composites were prepared by the carbonization of polyaniline (PAn) coated on silicone powder. The physical and electrochemical properties of the Si-C composites were characterized by particle-size analysis, X-ray diffraction, scanning electron microscopy, and battery electrochemical tests. The average particle size of Si was increased by the coating of Pan but somewhat reduced by the carbonization to give silicone-carbon composites. The co-existence of crystalline silicone and amorphous-like carbon was confirmed by XRD analyses. SEM photos showed that the silicone particles were well covered with carbonaceous materials, depending on the PAn content. Si-CILi cells were fabricated using the Si-C composites and tested using galvanostatic charge-discharge. Si-CILi cells gave better electrochemical properties than SilLi cells. Si-CILi cells using Si-C from HCl-undoped precursor PAn showed better electrochemical properties than precursor PAn doped in HCl. The addition of an electrolyte containing 4-fluoroethylene carbonate (FEC) increased the initial discharge capacity. Also, another electrochemical test, the galvanostatic charge-discharge test with GISOC (gradual increasing of the state of charge) was carried out. Si-C(Si:PAn = 50:50 wt. ratio)lLi cell showed 414 mAh/g of reversible specific capacity, 75.7% of TIE (initial intercalation efficiency), 35.4 mAh/g of IICs (surface irreversible specific capacity). |
