Synthesis and improved electrochemical performances of porous Li3V2(PO4)3/C spheres as cathode material for lithium-ion batteries

Spherical Li3V2(PO4)(3)/C composites are synthesized by a soft chemistry route using hydrazine hydrate as the spheroidizing medium. The electrochemical properties of the materials are investigated by galvanostatic charge-discharge tests, cyclic voltammograms and electrochemical impedance spectrum. The porous Li3V2(PO4)(3)/C spheres exhibit better electrochemical performances than the solid ones. The spherical porous Li3V2(PO4)(3)/C electrode shows a high discharge capacity of 129.1 and 125.6 mAh g(-1) between 3.0 and 4.3V, and 183.8 and 160.9 mAh g(-1) between 3.0 and 4.8V at 0.2 and 1 C, respectively. Even at a charge-discharge rate of 15 C, this material can still deliver a discharge capacity of 100.5 and 121.5 mAh g(-1) in the potential regions of 3.0-4.3 V and 3.0-4.8 V, respectively. The excellent electrochemical performance can be attributed to the porous structure, which can make the lithium ion diffusion and electron transfer more easily across the Li3V2(PO4)(3)/electrolyte interfaces, thus resulting in enhanced electrode reaction kinetics and improved electrochemical performance. (C) 2011 Elsevier B.V. All rights reserved.