Conducting polyaniline-wrapped lithium vanadium phosphate nanocomposite as high-rate and cycling stability cathode for lithium-ion batteries

This work introduces a facile strategy to improve the high-rate capability and cycling stability for carbon-free Li3V2(PO4)3 by coating with conducting polymer polyaniline. Core-shell Li3V2(PO4)3/polyaniline nanocomposite with typical sizes of 200 nm has been synthesized via a microwave heating assisted sol-gel method followed by a self-assembly process. The highly conductive and uniform polyaniline layer coated on the surface of Li3V2(PO4)3 nanoparticles significantly enhances the electrochemical performance of the electrode, which exhibits better rate capability and excellent cycling stability compared with the pristine Li3V2(PO4)3. The resultant nanocomposite exhibits a high initial discharge capacity of 130.7 mAhg−1 at 0.1 C within a voltage range of 3.0-4.3 V. When cycled at a rate of 10 C the capacity can reach up to 101.5 mAhg−1, and the capacity retention is 87.3% after 500 cycles. The likely contributing factor to the excellent electrochemical performance of core-shell Li3V2(PO4)3/polyaniline could be related to the uniform conducting polymer layer, which can improve the electrical conductivity of Li3V2(PO4)3.