Enhanced rate performance of Li3V2(PO4)3/C cathode by an improved rheological phase assisted microwave method

Highlights: • Rheological phase assisted microwave can utilize both advantages of two methods. • Polyethylene glycol was used as both rheological medium and carbon precursor. • 101.8 mA h g⁻¹ of specific capacity was obtained at 50 C rates. - Abstract: In this study, high-rate Li₃V₂(PO₄)₃/C composite is successfully synthesized via an improved rheological phase assisted microwave method using polyethylene glycol as both rheological medium and carbon precursor. The relatively uniform Li₃V₂(PO₄)₃ particles are encapsulated in amorphous carbon architecture to form core-shell structure, providing effective electron and ion transport. When used as a cathode material in lithium ion battery, the Li₃V₂(PO₄)₃/C composite displays a maximum discharge capacity of 101.8 mA h g⁻¹ at 50 C charge/discharge rate and still possesses 98.3% of capacity retention after 100 cycles, demonstrating superior rate capability and excellent cycling stability when compared with bare Li₃V₂(PO₄)₃. The observed electrochemical performance could be attributed to uniform coated-carbon pyrolysis from polyethylene glycol rheological phase precursor and small Li₃V₂(PO₄)₃ pristine particles synthesized by the fast microwave heating route.