Investigation of solid electrolyte interface (SEI) film on LiCoO2 cathode in fluoroethylene carbonate (FEC)-containing electrolyte by 2D correlation X-ray photoelectron spectroscopy (XPS).

Highlights: [•] Effect of fluoroethylene carbonate (FEC) on the electrochemical performance of the LiCoO2 cathode. [•] Solid electrolyte interface (SEI) film formation on the LiCoO2 cathode during overcharge state. [•] Reduced electrode/electrolyte interfacial impedance in FEC additive electrode. [•] Mechanism of the electrochemical reaction at the electrode/electrolyte interface. [ABSTRACT FROM AUTHOR]