An Extremely Fast Charging Li₃V₂(PO₄)₃ Cathode at a 4.8 V Cutoff Voltage for Li-Ion Batteries

Abstract

Extremely fast charging (XFC) is currently a crucial technology for lithium-ion batteries (LIBs) for addressing the concerns over the range and charging problems of electric vehicles. However, attaining both a high power density and a high energy density is a known challenge in electrochemical systems. Here, we report that Li3V2(PO4)3 can be an XFC cathode for high-voltage LIBs. Contrary to conventional belief, Li3V2(PO4)3 at a cutoff voltage (named CoV hereafter) of 4.8 V exhibits a rate performance and a cyclability that are better than those at a CoV of 4.3 V. The energy density based on an electrode can even exceed the theoretical value of LiFePO4, and the power density is comparable to that obtained from supercapacitors. Empirical characterizations are complemented with first-principles density functional theory calculations to determine the reaction mechanism and the diffusion pathways of the third Li+ in Li3V2(PO4)3. Moreover, the slow capacity decay mechanism of Li3V2(PO4)3 at a high CoV was elucidated by the differential capacity curve method.