锂离子电池用石墨材料的结构与性能研究

Structure and characteristics study of graphite for anode of Li-ion batteries

研究了锂离子电池用石墨材料的结构与物理及化学特性对其电化学性能的影响。采用XRD、BET、ICP、激光粒径分析等方法 ,对多种典型石墨样品的结构、比表面积、杂质含量、粒径分布进行了表征分析。随着石墨颗粒粒径的增大 ,石墨试样的比表面积减小。电化学性能测试表明 :在石墨材料的石墨化度非常接近的情况下 ,粒径和比表面积对电化学性能的影响较为突出 ,粒径较大及比表面积较小的石墨材料具有较好的充放电性能。试样D具有较高的可逆容量 ( 2 62mAh/g)和较低的不可逆容量损失 ( 85mAh/g) ,首次充放电效率为 75 .5 % 。

The effects of structure of graphite on its electrochemical performance were studied. The structures and characteristics of graphite were measured by means of powder X-ray diffraction (XRD), brunauer-emmer-teller (BET) surface area measurement, inductively coupled plasma (ICP) spectroscopy, particle size analysis. As the average particle size increased, the specific area of graphite decreased. According to the electrochemical measurement, the effects of particle size and specific area on the electrochemical performance of graphite anodes were obvious, the graphite anode with larger particle size and smaller specific area had better charge/discharge characteristics. The sample D had a reversible capacity of 262?mAh/g, and a irreversible capacity of 85?mAh/g, an initial coulombic efficiency of (75.5%),it was a suitable material for anode of Li-ion batteries.