Electrochemical characteristics of phosphorus doped Si-C composite for
anode active material of lithium secondary batteries
(1. Battery Research Center, Korea Institute of Science and Technology, P.O. Box 131,
Cheongrayng, Seoul, 130-650, Korea;
2. Department of Chemical and Biological Engineering, Korea University, Seoul, 136-791, Korea)
Cheongrayng, Seoul, 130-650, Korea;
2. Department of Chemical and Biological Engineering, Korea University, Seoul, 136-791, Korea)
Abstract: Phosphorus doped silicon-carbon composite particles were synthesized through a DC arc plasma torch. Silane(SiH4) and methane(CH4) were introduced into the reaction chamber as the precursor of silicon and carbon, respectively. Phosphine(PH3) was used as a phosphorus dopant gas. Characterization of synthesized particles were carried out by scanning electron microscopy(SEM), X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS) and bulk resistivity measurement. Electrochemical properties were investigated by cyclic test and electrochemical voltage spectroscopy(EVS). In the experimental range, phosphorus doped silicon-carbon composite electrode exhibits enhanced cycle performance than intrinsic silicon and phosphorus doped silicon. It can be explained that incorporation of carbon into silicon acts as a buffer matrix and phosphorus doping plays an important role to enhance the conductivity of the electrode, which leads to the improvement of the cycle performance of the cell.
Key words: secondary batteries; anode; silicon-carbon composite; phosphorus doping; arc plasma pyrolysis