Surface properties of fluoroethylene carbonate-derived solid electrolyte interface on graphite negative electrode by narrow-range cycling in cell formation process

Graphical abstract: - Highlights: • A new method to improve cell performance through an FEC-derived SEI layer on the graphite anode using narrow-range cycling in the formation process is presented. • A linkage structure of submicron-sized particles on the SEI film layer largely developed by narrow-range cycling in the formation process. • The application of narrow-range cycling with an FEC additive in the formation process improves the cycling performance and Coulombic efficiency of the cell. - Abstract: A modified solid electrolyte interface (SEI) on a graphite negative electrode with a fluoroethylene carbonate (FEC) additive was prepared by narrow-range cycling in a cell formation process. The SEI surface properties were investigated by extreme high-resolution scanning electron microscopy (XHR-SEM) under low acceleration voltage and X-ray photoelectron spectroscopy (XPS). A linkage structure of submicron-sized particles on the SEI film layer largely developed by narrow-range cycling in the formation process; these particles were mainly composed of the inorganic component (P-F bonding states, LiP_xO_yF_z) from the FEC. The application of narrow-range cycling with an FEC additive in the formation process improves the cycling performance and Coulombic efficiency of the cell. It is suggested that the SEI layer modified with FEC-derived SEI components on the graphite anode electrode by narrow-range cycling in the formation process, could improve the cell performance