片状LiFePO4/C正极材料制备及其电化学性能研究

在温和的反应条件下,使用十二烷基苯磺酸钠(SDBS)成功合成了片状二水磷酸铁,并将其与氢氧化锂、柠檬酸球磨混合,采用碳热还原法制备了具有纳米厚度的片状LiFePO₄/C电极材料。研究了SDBS对磷酸铁形貌以及LiFePO₄/C电极材料电化学性能的影响。利用X-射线衍射、扫描电子显微镜和充放电测试等技术手段,对合成样品的物相、形貌和电化学性能进行了分析测试。电化学测试表明,在25℃,2.0～4.2 V电压范围条件下,使用片状二水磷酸铁为前驱体制备的LiFePO₄/C样品,在0.1 C下放电比容量高达166.4 mA·h·g^-1,且首次库仑效率达到99.6%,在1 C下循环500次容量保持率为99%,表现出了优异的电化学性能。

Preparation of LiFePO4/C plate cathode materials and their electrochemical properties

Under mild reaction conditions, flaky iron phosphate dihydrate was successfully synthesized using sodium dodecyl benzene sulfonate (SDBS), and mixed with lithium hydroxide and citric acid by ball milling, and prepared by carbothermal reduction method. The effects of SDBS on FePO₄·2H₂O morphology and the electrochemical properties of LiFePO₄/C were studied. The phase, morphology and electrochemical properties of the synthesized samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and charge-discharge test. The LiFePO₄/C plate-like electrode material achieves excellent electrochemical performance under 2.0—4.2 V at 25℃. It delivers a specific discharge capacity of 166.4 mA·h·g^–1 at 0.1 C with initial Coulombic efficiency up to 99.6% and exhibits a capacity retention of 99% after 500 cycles at 1 C.