Significantly improved electrochemical performance of CFx promoted by SiO2 modification for primary lithium batteries

CFx/SiO2 composites with different SiO2 sources have been synthesized as cathode materials for primary lithium batteries. The effect of modification with different SiO2 sources on the performance of CFx has been investigated with FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), BET, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements (galvanostatic discharge, EIS). Based on the FT-IR and XPS analyses, it is confirmed that semi-ionic C-F has existed in SiO2 modified CFx and the F/C has decreased which may be caused by the reaction between SiO2 and CF2. The BET illustrated that the surface area of SiO2 modified CFx was extremely larger than that of pristine CFx. Furthermore, electrochemical measurements displayed an enhancement in the discharge capacity and plateau of the CFx/SiO2 composites, as well as an improvement in their power density and energy density. In particular the CFx-mSiO(2) exhibits a discharge capacity of 587 mA h g(-1), with a plateau of 2.28 V at a current density of 5C, accompanied by a maximum power density of 9689 W kg(-1) and about three times higher energy density than that of pristine CFx.