In situ repairing solid electrolyte interphase of faded graphite electrodes using a temperature–voltage coupling method

The thickening of the solid electrolyte interphase (SEI) increases battery polarization and severely impedes the long cycle life of graphite electrodes. We developed an in situ temperature–voltage coupling method that factors high temperature and high anode potential to decrease the SEI thickness of graphite anodes. A thin and inorganics-rich SEI film is formed upon graphite anode by the method, which is electrochemically and thermally stable. Electrochemical studies revealed that the impedance of the SEI film decreased when the Li/graphite–steel half cells were charged. X-ray photoelectron spectroscopy analysis verified that the proposed method promoted organic-component decomposition within the SEI film. Transmission electron microscope analysis of the morphology revealed SEI thickness reduction. The SEI thickness is plummeted using the proposed method. Thus, this research introduces an innovative method to reconstruct a compact and thin SEI film on the faded graphite anode surface.