Abstract:

Molar ratio of Li and Fe，glucose quantity，sintering time and temperature are four factors influencing the electrochemical properties of LiFePO₄/C cathode material. By using an improved solid-state reaction，an orthogonal test with four factors and three levers was designed to optimize the synthesis conditions of LiFePO₄. Some cathode materials with excellent electrochemical performance were synthesized under these optimized conditions. Structure and electrochemical properties of the produced materials were caracterized by using XRD，SEM，cyclic voltammetry and electrochemical impedance spectra. Without using ball milling，this improved solid state reaction method is propitious to industrial production. The first discharge specific capacities of the optimized samples were 133.2 mAh/g at 0.2 C and 112.5 mAh/g at 1.0 C under room temperature. After 30 cycles，the capacity at 0.2 C remained stable at about 133.1 mAh/g and fell down to 106.8 mAh/g at 1.0 C.

摘要：

锂铁比、葡萄糖加入量、焙烧温度、焙烧时间是影响LiFePO₄正极材料电化学性能的4个重要因素。本文使用改进的固相法设计出一个四因素三水平的正交实验，对LiFePO₄/C正极材料进行了优化合成，探讨了其优化合成条件，并合成出具有优良电化学性能的LiFePO₄/C正极材料。使用XRD、SEM对合成产物进行结构分析；使用循环伏安、交流阻抗、放电比容量等对正极材料的电化学性能进行分析。此方法不使用球磨机，有利于工业化生产。室温下0.2 C倍率首次放电比容量为133.2 mAh/g，1.0 C倍率容量为112.5 mAh/g；30次循环活化后，0.2 C倍率容量稳定保持在133.1 mAh/g左右，1.0 C倍率容量则下降至106.8 mAh/g。