MIL-101 derived VOPO₄/C nanocomposite as high energy density cathode for lithium ion batteries

VOPO₄ is a potential cathode candidate in lithium-ion batteries owing to its layered structure to attain a high capacity for large scale applications. However, the reported efforts could only manage to achieve a moderate capacity. Here, we report a simplified strategy to synthesize an anhydrous α_I-VOPO₄ polymorph in the form of nanoflakes with nanoporous carbon in the form of a nanocomposite cathode for a 3.8 V lithium-ion battery offering a high specific capacity of 158.5 mAh g⁻¹. Electrochemical analysis suggests a highly efficient cathode performance derived from a large plateau at 3.7 V vs Li/Li⁺ resulting in an energy density of 591.21 Wh/kg. The layered VOPO₄/C based cathode offered a smooth intercalation/extraction of Li⁺ to maintain a stable structure over long-term cycling, resulting in an overall 87.7 % capacity retention after 100 cycles and an excellent rate capability. The promising electrochemical performance results from the synergistic effect of excellent conductivity of nanoporous carbon embedded with the uniform dispersion of kinetically active VOPO₄ nanoflakes.