Li₃V₂(PO₄)₃/graphene nanocomposites with superior cycling performance as cathode materials for lithium ion batteries

Li₃V₂(PO₄)₃ (LVP) nanoparticles were first prepared via a simple sol-gel route, then deposited on graphene oxide nanosheets, and finally a composite of LVP/reduced graphene oxide (LVP/G) was obtained after heat treatment. Scanning electron microscope and transmission electron microscope images demonstrate that LVP nanoparticles are homogenously enwrapped into graphene nanosheets or anchored onto the surface of graphene nanosheets. Compared with pure LVP, LVP/G nanocomposites exhibited better electrochemical performance (118.4 mAhg⁻¹ at 1C, and 112.1 mAhg⁻¹ at 2C after 100 cycles) and higher cycling stability (97% capacity retention after 100 cycles at 1C, and 89.5% after 500 cycles at 20C) as cathode materials for Li ion batteries. The enhanced performance can be attributed to the presence of graphene nanosheets among LVP nanoparticles. Electrochemical impedance spectroscopy indicates that graphene nanosheets significantly improve the electrical conductivity of LVP. The as-prepared LVP/G nanocomposites with superior cycling performance at high-rate have potential applications as cathode materials in Li ion batteries.