Raising the capacity of lithium vanadium phosphate via anion and cation co-substitution

Abstract

The pursuit for batteries with high specific energy provokes the research of high-voltage/capacity cathode materials with superior stability and safety as the alternative for lithium iron phosphate. Herein, using the sol-gel method, a lithium vanadium phosphate with higher average discharge voltage (3.8 V, vs. Li+/Li) was obtained from a single source for Mg2+ and Cl− co-substitution and uniform carbon coating, and a nearly theoretical capacity (130.1 mA h g−1) and outstanding rate performance (25 C) are acquired together with splendid capacity retention (80%) after 650 cycles. This work reveals that the well-sized anion and cation substitution and uniform carbon coating are of both importance to accelerate kinetic performance in the context of nearly un-disturbed crystal structure for other analogue materials. It is anticipated that the electrochemistry comprehension will shed light on preparing cathode materials with high energy density in the future.