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采用共沉淀法以正硅酸乙酯、硫酸亚铁、碳酸锂为原料,并加入了导电炭黑制备了Li2FeSiO4/C前驱材料,前驱体在高温(800℃)氩气气氛中进行焙烧得到了Li2FeSiO4/C正极材料。利用X射线衍射、扫描电镜对样品进行表征,并组装成电池,通过了交流阻抗(EIS)、恒流充放电测试研究其电化学性能。结果表明:该方法制备的Li2Fe Si O4/C晶型良好,晶粒分布均匀,晶粒尺寸在400~600 nm;材料的电导率为2.21×10-13m2s-1,室温下0.1、0.2、0.5、1C(1C=166 m A/g)电流放电,放电容量分别达到了163.5、152.5、113.6、106.1m Ah/g,0.2 C放电下循环放电容量较稳定。
Li2FeSiO4 / C precursor was prepared by co-precipitation method using tetraethoxysilane, ferrous sulfate and lithium carbonate as raw materials and conductive carbon black was added. The precursors were calcined in a high temperature (800 ℃) argon atmosphere Li2FeSiO4 / C cathode material. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The samples were assembled into batteries and their electrochemical properties were tested by electrochemical impedance spectroscopy (EIS) and constant current charge-discharge test. The results show that the prepared Li2FeSiO4 / C has good crystal form and uniform grain size with the grain size of 400-600 nm. The conductivity of the material is 2.21 × 10-13m2s-1, and the room temperature 0.1, 0.2, 0.5 , 1C (1C = 166 m A / g). The discharge capacity reached 163.5, 152.5, 113.6 and 106.1 m Ah / g respectively, and the discharge capacity was stable under 0.2 C discharge.