Nanostructured Li3V2(PO4)3/C composite as high-rate and long-life cathode material for lithium ion batteries

Nanostructured Li3V2(PO4)(3)/C composite has been synthesized by a facile microemulsion method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results confirm that the as-prepared Li3V2(PO4)(3)/C sample shows the pure monoclinic structure and nanosphere morphology. Li3V2(PO4)(3)/C has a particle size of about 100 nm, and these nanoparticles are connected each other by the conductive carbon network. Electrochemical measurements demonstratethat the Li3V2(PO4)(3)/C nanoparticles can deliver discharge capacities of 129.8, 126.1, 118.0, 116.1 and 110.1 mAh g(-1) between 3.0 and 43 V, and 171.4, 163.1, 153.2, 144.0 and 133.4 mAh g(-1) between 3.0 and 4.8V at 1, 2, 5, 10 and 20C, respectively. Even at 20C rate, it still can present a reversible discharge capacity of 101.8 mAh g(-1) with 92.5% capacity retention after 1400 cycles and 96.4 mAh g(-1) with 72.3% capacity retention after 1000 cycles in the potential ranges of 3.0-4.3 V and 3.0-4.8 V, respectively. The excellent rate capability and long-term cycle performance demonstrate that the Li3V2(PO4)(3)/C nanoparticles prepared in this work has great potential for application as cathode materials in high-power lithium ion batteries. (C) 2014 Elsevier Ltd. All rights reserved.