1,1,2,2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether as an advanced electrolyte additive for SiOx-based lithium-ion batteries

Abstract

SiOx has recently attracted considerable attention as an electrode material for lithium-ion batteries (LIBs) due to its high energy density. However, the constant pulverization of SiOx material from severe volume expansion/extraction significantly degrades the cycling performance of the cell. Here, the interfacial stability of SiOx anode materials is enhanced by adding a 1,1,2,2-tetrafluoroethylene-2,2,3,3-tetrafluoropropyl ether (TFE) electrolyte to form artificial solid-electrolyte interphases (SEIs) on the surface of the SiOx anode. Electrochemical reduction of the TFE additive results in a robust LiF-based SEI layer that adequately stabilizes the interfacial characteristics of the SiOx anode. Electrochemical cycling confirms that adding 10 wt% TFE to the standard electrolyte significantly enhances the lifespan of a cell assembled with SiOx/NCM811 electrode materials. Scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy investigations demonstrates that artificially produced SEI layers efficiently prevent the pulverization of SiOx anode materials caused by electrolyte degradation in the cell.