溶胶-凝胶法制备LiFePO_4/C及其电化学性能

Synthesis and Electrochemical Properties of LiFePO_4/C by Sol-Gel Method

以硝酸铁、磷酸二氢铵、氢氧化锂为原料,以聚乙二醇PEG-4000为螯合剂和碳源,采用溶胶-凝胶法制备了LiFePO4/C。利用XRD、SEM、电化学性能测试等手段对LiFePO4/C的物相结构、形貌、电化学性能进行表征。结果表明:PEG-4000作为螯合剂和碳源,使得样品的粒径较小且分布均匀。650℃烧结18h所合成的样品具有最佳的电化学性能,0.1C首次充、放电容量分别为152.7、150.6 mAh/g;循环30次后容量为146 mAh/g,容量衰减率为3.05%。

LiFePO4/C samples were synthesized by sol-gel method using Fe（NO3） 3 · 9HEO,NH4H2PO4 and LiOH · H20 as raw materials and polyethylene glycol PEG-4000 as chelating agent and carbon source. The crystal structure, morphology and electrochemical properties of LiFePO4/C were characterized by XRD, SEM and electrochemical performance tests. The results showed that PEG-4000 as chelating agent and carbon source made the sample being of small particle size and uniformly distributed. The LiFePO4/C sample sintered for 18 h at 650 ℃ presented optimal electrochemical performance with the initial charge and discharge capacities of 152.7 mAh/g and 150.6 mAh/g at 0.1C, a capacity of 146 mAh/g and a capacity decay rate of 3.05% after 30 cycles.