溶胶凝胶法制备LiFePO4／C正极材料及电化学性能研究

以柠檬酸铁铵为络合剂、铁源以及碳源，去离子水为溶剂，LiH2PO4作为锂源，采用溶胶凝胶一步烧结法制备了LiFePO4／c正极材料。利用x射线衍射，扫描电子显微镜以及恒电流充放电测试对材料的结构形貌和电化学性能进行表征。结果表明：该方法制备的材料为单一的橄榄石结构，无杂质相存在；材料具有多孔状结构，该结构有利于电子离子的传导，颗粒粒径大约为200-300nm之间；在室温与-20℃下分别以0．1C、1C、10C倍率充放电，其比容量为168mAh／g、120mAh／g、54mAh／g与106mAh／g、65mAh／g、28mAh／g，且10次循环后容量几乎无衰减。材料具有良好的容量及循环性能。

ELECTROCHEMICAL PERFORMANCE OF LiFePO4/C CATHODE PREPARED BY SOL-GEL METHOD

The LiFePO4/C was synthesized by an aqueous sol-gel method used ferric iron precursor as iron source, ammonium ferric citrate as chelating agent and carbon source. The materials were characterized by X-ray diffraction, scanning electron microscope and charge-discharge tests. The results show that the materials prepared by this method have the pure olivine phase structure. The materials also have a porous structure, which is favorable to the conductivity. Its specific capacities are 168 mAh/g, 120 mAh/g, 54 mAh/g and 106 mAh/g, 65 mAh/g, 28 mAh/g under 0.1 C, 1 C, 10 C charge-discharge rates at room temperature and -20℃. Its capacities have almost no decay after 10 cycles.