Electrochemical Investigation of the Novel LiVPO4F Cathode Material in Lithium Ion Cells

Abstract

LiVPO4F is a novel fluorophosphate cathode material that promises to deliver good rate capability, long cycle life, safety, high energy density, and high voltage, in lithium ion cells. As with phosphate cathode materials, in LiVPO4F the phosphate polyanion creates a strong inductive effect, while the strength of the P-O bonding limits availability of oxygen for exothermic reactions with electrolyte solvent. The addition of fluorine intensifies the inductive effect, enabling new structural possibilities with as yet unexplored redox couples: LiVPO4F crystallizes in the triclinic structure, analogous to amblygonite (LiAlPO4F, space group P .) With insertion potential at a voltage of 4.2V versus lithium, LiVPO4F merits further study as a candidate high voltage, high energy density cathode material. Our investigation studied the rate capability and cycling performance of LiVPO4F in lithium ion cells