以天然石墨为原料，球磨过筛得到颗粒均一的球形颗粒。酚醛树脂作为碳源对球磨后石墨进行包覆，经过高温炭化处理，在天然石墨表面形成一层炭包覆层，再对包覆后石墨用聚二甲基硅氧烷进行表面预成膜处理。采用X射线衍射仪、扫描电子显微镜和电池测试系统等对共改性石墨进行结构、形貌和电化学性能分析。XRD分析显示，共改性后的石墨层间距d（002）和无序化程度增加，说明在石墨的表面形成了一定的包覆层。SEM图片中可以看出改性后的石墨颗粒致密均匀且较为圆滑，这种结构使得石墨颗粒表面积适当减小，电化学性能得到提高。电化学性能测试结果表明，采用共改性后的石墨在0．1 C首次放电比容量达到362 mAh/g，首次库伦效率为92％，100个循环后容量仍保持为最高容量的98．6％。%The natural graphite with uniform spherical graphite particles was gotten through ball milling sieve processing.Carbon-coated natural graphite composite was prepared by carbonization of phenolic resin-coated natural graphite at high temperature,and the coated graphite was pre filmed with polydimethyl siloxane on the surface.X-ray diffraction (XRD),scanning electron mi-croscopy (SEM)and battery test system were used to characterize the crystal structure,mor-phology and electrochemical properties of samples.XRD results showed that phenolic was suc-cessfully coated on the surface of natural graphite because d (002 )and the disorder degree in-creased.SEM images indicated that the graphite particles was uniform and smooth,and this kind of structure made graphite surface area reduced,the electrochemical performance was improved. Electrochemical performance revealed that the capacity of compound modification graphite was 362 mAh/g at 0.1 C,coulomb efficiency was 92% for the first time.After the 100 th cycle,the capacity remained 98.6% of the highest capacity.
展开▼
