Effect of synthesis temperature, time, and carbon content on the properties and lithium-ion diffusion of LiFePO4/C composites

• DOI: 10.1007/s10008-014-2481-4
• Publication Date: 2014-05-08T02:59:35Z
• Authors: Na Zhang; Lin Lin; Zemin Xu
• Keywords: 02 engineering and technology; 0210 nano-technology

LiFePO4/C cathode materials were synthesized by hydrothermal process and subsequently annealed process. The influence of the processing parameters on the structure properties including crystallite size, lattice parameters, and (020) crystallographic direction of the samples prepared at different conditions were investigated by X-ray powder diffraction (XRD). In order to determine the influence of vacancies and inter-site Fe mixing on the lithium diffusion coefficients, the subsequent electrochemical impedance spectra (EIS) measurements and cyclic voltammogram (CV) measurements were carried out. We believe that the sample prepared at optimized conditions of synthesis temperature at 180 °C for 3 h and subsequently calcined at 750 °C for 60 min with the mass ratio (LiFePO4 precursor to glucose) of 1:0.1 had higher purity, higher crystallinity, some preferred crystal orientation with a (020) texture, and higher lithium diffusion coefficients, moreover, exhibits excellent rate performance and cycling stability at room temperature.