Investigation of Lithium Tetrafluorooxalatophosphate as a Lithium-Ion Battery Electrolyte

A lithium tetrafluorooxalatophosphate [LiPF4(C2O4)] salt, was prepared and its properties as a lithium-ion battery electrolyte were investigated. The conductivity, electrochemical stability, and cycling performance of 1.0 M LiPF4(C2O4) in 1:1:1 ethylene carbonate/dimethyl carbonate/diethyl carbonate are comparable to the industry standard LiPF6 electrolyte. While the reversible capacity of the first cycle is lower than LiPF6-based electrolytes, the reversible cycling efficiency is equivalent. Electrochemical impedance spectroscopy and electrode surface analysis provide insight into the differences between LiPF6 and LiPF4(C2O4).