柠檬酸包覆合成LiFePO4／C工艺的优化

Study on the optimum processing conditions of citric acid coated LiFePO_4/C composite materials

以柠檬酸为碳源,采用机械液相球磨与高温固相烧结相结合制备了LiFePO4/C复合材料,考察了烧结温度、烧结时间、柠檬酸用量、球磨时间等工艺条件对LiFePO4/C材料性能的影响。采用XRD、SEM和恒电流充放电等手段对该材料进行结构表征和电化学性能测试。结果表明,合成LiFePO4/C复合正极材料的适宜工艺为,球磨时间10h,烧结温度600℃,烧结时间18h,柠檬酸用量10%,气体流量0.6L/min。在优化工艺条件下制备的LiFePO4/C复合正极材料首次放电容量可达到146.2mAh/g。

LiFePO4/C composite materials using citric acid as the carbon source were synthesized by means of a high temperature solid sintering process combined with a liquid-phase mechanical ball milling technique. The effect of process conditions, such as sintering temperature and time,citric acid dosage, ball-milling time etc. , on the properties of as-synthesized cathode materials were investigated. The crystal structure and the electrochemical performance were characterized by XRD,SEM and galvano-static charge-discharge method. The results show that the optimum processing conditions of synthesizing LiFePO4/C composite materials are 10h ball-milling,and sintered at 600℃（2 for 18h,with 10% citric acid and Ar gas flow rate of 0.6L/min. LiFePO4/C composite materials synthesized under the optimum processing conditions has a first-capacity of 146.2mAh/g.