Fabrication of LiVOPO4/carbon composite via glass-ceramic processing

Carbon coating of β-LiVOPO4 produced by glass-ceramic processing was carried out by the pyrolysis of glucose. Li2O-V2O2-P2O5 (LVP) glass-ceramics were produced by heat treatment at 400 deg. C (sample α1), 600 deg. C (sample β1) and 600+720 deg. C (sample β2). Sample β1 was subsequently heat treated in the presence of glucose at 500 and 600 deg. C in a N2 atmosphere to produce samples β2 and β3, respectively. From X-ray diffraction (XRD) and differential thermal analyses, it was found that sample β1 consisted mainly of β-LiVOPO4 crystals and did not contain any other crystalline phases. However, in samples β2 and β3, decomposition of LiVOPO4 took place due to the strongly reducing effect of residual carbon. For sample β3, XRD diffraction peaks associated with Li3V2(PO4)3 were found. From the charge-discharge measurements, the decomposed LVP glass-ceramics were also found to act as active materials. However, samples β2 and β3 exhibited Li3V2(PO4)3-like and solid-solution behaviour, respectively.