The influence of different ball-milling dispersants on the structure and performance of Li₃V₂(PO₄)₃/C composites

The Li₃V₂(PO₄)₃/C (LVP/C) composite materials have been synthesized with different volume ratio of ethanol and water as ball-milling dispersants. The samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical tests. When pure ethanol or water is adopted as ball-milling dispersant, the synthesized LVP/C composite exhibits uniform carbon coating layer with adequate thickness restricting the excessive growth of LVP grains and agglomeration of LVP/C particles, which provides efficient electronic conduction networks as well as good electrochemical reactivity. At 1C rate, the initial discharge capacity of the LVP/C composite synthesized with pure ethanol as dispersant reaches 122.5mAh g-1, which is slightly larger than the sample synthesized with pure water as dispersant (119.6mAh g^-1). However, at 10C and 20C rates, both the samples deliver the same initial discharge capacity and cycling stability. The CV and EIS tests show that the lithium-ion diffusion coefficients of the two samples are of the same order of magnitude, indicating that they both have good mass-transport capability.