Performance of lithium tetrafluorooxalatophosphate (LiFOP) electrolyte with propylene carbonate (PC)

The cycling performance of LiPF4(C2O4) (LiFOP) electrolyte with propylene carbonate (PC) as a cosolvent is compared with LiPF6 electrolyte with ethylene carbonate (EC) as a cosolvent in the presence of different cathode materials, such as LiNi1/3Co1/3Mn1/3O2 and LiFePO4. The cycling performance of cells with LiFOP and PC is similar to cells with LiPF6 with EC at room temperature and superior at low temperature (−10 °C). After thermal abuse the room temperature performance of cells with LiFOP electrolyte and PC is worse than cells with LiPF6 and EC. A detailed analysis of the surface films on both the anode and the cathode via X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Fourier transfer infrared spectroscopy (FT-IR) in the attenuated total reflection (ATR) mode was conducted to provide a better understanding of performance differences.

► New electrolyte for lithium ion battery electrolytes was investigated. ► LiPF4(C2O4) electrolytes with propylene carbonate is an alternative to state-of-art LiPF6 ethylene carbonate electrolytes. ► LiPF4(C2O4) allows reversible cycling in the presence of propylene carbonate. ► Surface analysis of the electrodes after cycling was conducted.