Enhanced electrochemical performance of multi-walled carbon nanotubes modified Li2FeSiO4/C cathode material for lithium-ion batteries

The multi-walled carbon nanotubes (MWCNTs) modified Li2FeSiO4/C composite is synthesized via a citric acid-based sol-gel method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, galvanostatic charge/discharge measurements, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) tests. The Li+ diffusion coefficient in Li2FeSiO4/C/MWCNTs is larger than that in Li2FeSiO4/C. Compared with (LiFeSiO4)-Fe-2/C, (LiFeSiO4)-Fe-2/C/MWCNTs electrode can extract more than 1 mol Li+ and exhibit better electrochemical performance with a high discharge capacity of 206.8 mA h g(-1) in the second cycle, especially, an excellent high-rate capacity and cycle stability. The enhanced electrochemical performance is attributed to the reduced particle size and the high conducting network between the MWCNTs and the (LiFeSiO4)-Fe-2/C particles. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.