Enhanced overall electrochemical performance of silicon/carbon anode for lithium-ion batteries using fluoroethylene carbonate as an electrolyte additive

In this paper, fluoroethylene carbonate (FEC) as an electrolyte additive is employed to improve the rated capability of a silicon/carbon (Si/C) anode for lithium-ion batteries. The electrochemical performance of the electrodes is investigated by a galvanostatic charge and discharge test in different FEC-containing electrolytes. A solid electrolyte interphase (SEI) film formed on the surface of the Si/C electrode is analyzed by electrochemical impedance spectroscopy (EIS), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The results show that the high rate performance and cycle life are obviously improved by the use of FEC as an electrolyte additive, which can be attributed to the more stable and denser SEI film formed on the electrode surface with the addition of FEC.