LiFePO4基正极材料容量的温度敏感特性及交流阻抗谱研究

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

摘要:

采用原位碳包覆法制备了锂离子二次电池用LiFePO4／C复合正极材料。考察了环境温度对LiFePO4/C电池容量的影响，得到容量与绝对温度之间符合Arrhenius关系。运用交流阻抗谱分析了温度与电池电化学特性的关系，并对电极基于电荷和质量传递控制过程给出了一种新的模拟等效电路，通过Zview拟合软件得到了各个模拟元件的数值及变化趋势，从而定量地解释LiFePO4／C复合电极容量与温度的关系。

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.