Li_2FeSiO_4/C正极材料的制备及电化学性能研究

Study on the preparation and electrochemical performance of Li_2FeSiO_4/C cathode material

以柠檬酸为络合剂,蔗糖为碳源,采用球磨和碳热还原法制备了Li2FeSiO4/C正极材料。研究了煅烧温度对材料的物理性质和电化学性质的影响。利用TG、XRD、SEM测试技术对材料的热稳定性、物相结构、形貌进行表征,通过恒电流充放电和循环伏安(CV)技术,对其电化学行为进行了分析。结果表明:制备的Li2FeSiO4/C样品均具有单一的正交晶系结构,在650℃煅烧10h制备的Li2FeSiO4/C材料电化学性能更好,以1/16C倍率放电,初始比容量为153.9mAh/g,循环30次后,其放电容量保持率为93.5%。

Li2 FeSiO4/C composite cathode was prepared by ball milling and carbon-thermal reduction process, using citric acid as chelating agent and sucrose as carbon source. The effect of the calcinations temperature on the physical and electrochemical properties of the Li2 FeSiO4/C composite was investigated. The thermostability, phase structure and surface morphology performance of Li2 FeSiO4/C composite were characterized by TG-DTG, SEM and XRD, respectively. The electrochemical performance of the composite was investigated by galvanostatic charge-discharge tests and cyclic voltammetry （CV）. The results showed that Li2FeSiO4/C was simple phase orthogonality-type. The material prepared at 650 ℃ for 10 h had the best electrochemical properties. The material showed the specific capacity of 153.9 mAh/g at 1/16 C,and after 30 cycles, the capacity of 93.5% had been maintained.