Structural and electrochemical characterization of 0.7LiFePO4·0.3Li3V2(PO4)3/C cathode materials using PEG and glucose as carbon sources

0.7LiFePO4·0.3Li3V2(PO4)3/C composites (LFVP/C) were synthesized via spray-drying technique followed by solid-state reaction approach using polyethylene glycol (PEG) and glucose as carbon sources. The samples were characterized by X-ray diffraction (XRD), X-ray absorption fine-structure spectroscopy (XAFS) and Raman spectroscopy. The results show that the bi-phase composite structure of LFVP/C contains olivine LiFePO4 (LFP) and monoclinic Li3V2(PO4)3 (LVP). The lower intensity ratio of the ID/IG and Asp3/Asp2 for PEG-200 indicates the formation of higher degree of graphitized carbon during the process, which would enhance the electronic conductivity. The composite obtained using PEG-200 as carbon source show excellent rate performance, delivering the discharge capacity of 120 mAh/g at the current density of 1.5 A/g.