Power fade in lithium ion batteries: Effect of advanced electrolyte.

Commercial lithium-ion batteries have excellent performance at room temperature for a few years (3-5). However, the calendar life and thermal stability (>50°C) need to be improved for many applications, including electric vehicles (EV). Power fade of lithium ion batteries results from electrolyte decomposition and solid electrolyte interface (SEI) deterioration on the surface of electrode materials. The purpose of investigation of advanced electrolyte, including the incorporation of a small amount of additives and novel lithium salts in the electrolyte, is to improve the thermal stability of both electrolyte and SEI on the electrodes. A detailed investigation of the effect of thermal stabilizing additives, including dimethyl acetamide (DMAc), vinylene carbonate (VC), lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (LiF 2OB) and lithium tetrafluoro (oxalato) phosphate (LiF4OP), on the reactions of the electrolyte with the surface of the anodes was conducted. The surfaces of the electrodes have been characterized with a combination of IR-ATR, XPS, TGA, and SEM-EDS. The role of the advanced electrolyte in SEI formation and stability is also discussed.