热处理温度对石墨复合负极材料电化学性能的影响

Effect of Heat Treatment Temperature on Electrochemical Performance of Graphite Composite Anode for Lithium Ion Battery

以球形天然石墨为原料,柠檬酸为碳源,通过喷雾造粒及高温热处理得到了高容量石墨复合(G/C)负极材料。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和高分辨率透射电子显微镜(HRTEM)对样品物相和微观形貌进行表征,并通过恒流充放电及循环伏安(CV)研究了不同热处理温度对G/C材料电化学性能的影响。2 900℃制得样品既具有石墨负极电压曲线特性,又可释放出远高于商品化石墨负极的比容量:首次循环活化后充电比容量为423 m Ah·g-1,100次循环后仍高达416 m Ah·g-1,容量保持率为98%。

The graphite composite（G/C） anode was prepared by spray drying and high temperature sintering using natural spherical graphite as raw material and citric acid as carbon source. X-ray diffraction（XRD）, scanning electron microscope（SEM） and high-resolution transmission electron microscope（HRTEM） were used to characterize crystal structure and morphology of samples. Galvanostatic charge-discharge tests and cyclic voltammentry（CV） were utilized to study the effect of heat treatment temperature on electrochemical performance of G/C anode. With typical voltage feature of graphite anode, G/C-2900 sample shows higher capacity than commercial graphite anode. The charge capacity of the G/C-2900 after the first activation is 423 m Ah·g-1, and the100 th charge capacity is 416 m Ah·g-1with capacity retention rate of 98%.