Temperature Sensitivity to Capacity of LiFePO4-Based Cathode Materials and AC Impedance Analysis

Abstract:

LiFePO4/C composition cathode was synthesized by a method of in-situ carbon coating. The influence of ambient temperature on the capacity of LiFePO4/C was investigated. The Arrhenius relationship between capacity and temperature was observed by linear fit and deduced. Temperature dependence of its electrochemical characteristic was evaluated by using AC impedance spectroscopy. A new equivalent circuit based on the charge and mass transfer control process in electrode was suggested to fit the obtained AC impedance spectra. The tendency of every element in equivalent circuit obtained by Zview fitting system was used to interpret the temperature dependence of capacity for LiFePO4/C composition cathode.