包覆工艺对天然石墨负极材料的结构和性能影响研究  

Effect of coating process on the structure and properties of natural graphite anode material

作　　者：刘亚雄 李国栋[1] 郭星 田晓冬[1] 宋燕[1,2] 刘占军 Liu Ya-xiong;Li Guo-dong;Guo Xing;Tian Xiao-dong;Song Yan;Liu Zhan-jun(Key Laboratory of Carbon Materials,Institute of Coal Chemistry,Chinese Academy of Sciences,Shanxi Taiyuan 030001,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院山西煤炭化学研究所中国科学院炭材料重点实验室,山西太原030001 [2]中国科学院大学材料与光电研究中心,北京100049

出　　处：《炭素技术》2022年第6期46-50,共5页Carbon Techniques

基　　金：山西省优秀博士引进资助项目(SQ2019001)。

摘　　要：以吡啶为溶剂、高软化点沥青为包覆剂,分别采用常压法和真空法对天然石墨进行沥青炭包覆改性处理,然后将得到的产物进行了SEM、TEM和XRD等分析测试,并将材料组装成半电池进行电化学性能测试。结果表明:2种包覆方法均可在天然石墨表面形成较为均匀的无定形炭层,覆盖了天然石墨的表面缺陷及边缘棱角。相比而言,真空法包覆产物的包覆层更为均匀致密。经过包覆后,材料的石墨化度降低,层间距增大,晶粒尺寸减小。电化学性能测试结果表明沥青炭包覆有助于提高材料的循环稳定性和大电流充放电性能,常压包覆产物的综合电化学性能更为优异。Natural graphite coated by pitch-based carbon is prepared by using pyridine as the solvent and high softening point pitch as the coating agent via atmospheric pressure method and vacuum method,respectively.The obtained products are analyzed by SEM,TEM and XRD,and further assembled into half cells for electrochemical performance testing.The results show that both coating approaches could form a uniform amorphous carbon layer on the surface of natural graphite,which is inductive to cover the surface defects and edge corners.In comparison,more uniform and compact layer is obtained by vacuum method.After coating,both the graphitization degree and grain size of the as-obtained products decrease,while the layer spacing increases.Compared with natural graphite,the modified graphite delivers better rate capability and improved cycling stability.Under the experimental conditions of this work,the results indicated that the best overall electrochemical performance can be obtained for the sample prepared via atmospheric pressure coating approach.

关 键 词：锂离子电池 天然石墨 沥青 液相包覆 

分 类 号：TM242[一般工业技术—材料科学与工程]