(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 采用分步碳包覆法合成LiFePO4/C复合材料。首先，将原料Fe2O3、NH4H2PO4和葡萄糖经过固相反应合成Fe2P2O7/C复合材料，再将Fe2P2O7/C与前驱体Li2CO3、葡萄糖混合，通过二次碳包覆工艺合成LiFePO4/C复合材料，并考察合成温度对LiFePO4/C复合材料电化学性能的影响。采用X射线衍射、扫描电镜、差热−热重分析、电化学阻抗谱(EIS)和充放电测试对材料的性能进行表征。结果表明：以制取的Fe2P2O7/C为前驱体合成的LiFePO4/C复合材料具有较好的物理和电化学性能，材料的振实密度达1.26 g/m3，0.1C放电容量为158.3 mA•h/g，1C初次放电比容量达到140 mA•h/g。
关键字: LiFePO4/C复合材料；Fe2P2O7；锂离子电池；正极材料
stepwise carbon-coating
（School of Metallurgy Science and Engineering, Central South University, Changsha 410083, China）
Abstract:LiFePO4/C composite was synthesized by stepwise carbon-coating. First, the precursor Fe2P2O7/C was obtained by solid state reaction with Fe2O3, NH4H2PO4 and glucose, then, LiFePO4/C was synthesized by mixing the precursor, Li2CO3 and glucose through stepwise carbon-coating process. The effect of synthesis temperature on the electrochemical performances of LiFePO4/C composites was studied. The product were characterized by XRD, SEM, DSC-TGA, EIS and charge-discharge test. The results show that the LiFePO4/C composites synthesized with Fe2P2O7 as the precursor have excellent physics and electrochemical performance, the tap density of product reaches 1.26 g/cm3, and it has discharge capacities of 158.3 mA•h/g at 0.1C and 140 mA•h/g at 1C.
Key words: LiFePO4/C composites; Fe2P2O7; lithium ion batteries; cathode materials
