Synthesis and electrochemical properties of Li3V2(PO4)3/MWCNTs composite cathodes

Multi-walled carbon nanotubes (MWCNTs)-doped lithium vanadium phosphate Li3V2(PO4)3 (LVP)/MWCNTsx (x = 0, 1, 3, 4, 5, 7 wt.%) cathode materials for lithium ion batteries are synthesized by a microwave assisted sol–gel method. Moreover, the influences of doped MWCNTs on the physicochemical and electrochemical properties of the as-prepared samples are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical experiments. The results show that the optimal doping amount of MWCNTs is 4 wt.%. Under this condition, the LVP/MWCNTs4 wt.% sample has an monoclinic structure, the average particle size is about 0.2–4 μm with very fine particle size, uniform shape and loose agglomeration. When charge/discharge at 0.1 C, the sample reached the maximum discharge capacity (130 mAh g−1), which is comparable to its theoretical capacity. Comparing with the sample obtained by conventional solid-state route, the obtained materials display lower charge transfer resistance, higher rate capability and excellent reversibility. The above experiments demonstrate that the LVP/MWCNTs4 wt.% is a very promising cathode material which will be used in the future for lithium ion batteries.