微晶石墨改性用作锂离子电池负极材料  

Microcrystalline graphite modified as lithium-ion battery anode material

作　　者：周奇 文博 谢志勇[1] ZHOU Qi;WEN Bo;XIE Zhiyong(State Key Laboratory for Powder Metallurgy,Central South University,Changsha 410083,China;School of Materials Science and Engineering,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]中南大学粉末冶金研究院,长沙410083 [2]湘潭大学材料科学与工程学院,湖南湘潭411105

出　　处：《功能材料》2023年第2期2167-2173,共7页Journal of Functional Materials

基　　金：国家重点研发计划子项目(2020YFB1505901)。

摘　　要：微晶石墨存在加工性能差、低首效的缺点,对此采用了高温石墨化、碳化包覆对微晶石墨进行改性,引入了超高分子羧甲基纤维素钠(CMC)作为分散剂。与改性前的微晶石墨对比,加工性能和电化学性能得到大幅度提升。利用激光粒度分布仪等表征了其物理性能,利用SEM等分析了微晶石墨的结构和表面形貌,利用浆料粘度的变化表征其加工性能,并通过扣电测试了其电化学性能。结果表明:高温处理后的微晶石墨扣电首效由64.2%提升至87.1%,克容量发挥275.2 mAh/g提升至343.3 mAh/g;包覆后的微晶石墨浆料稳定性更好,克容量发挥达到394 mAh/g;使用超高分子CMC保证浆料稳定性的同时,也改善电池的倍率性能。Microcrystalline graphite has the disadvantages of poor processability and low initial effect.For that reason,the microcrystalline graphite was modified by high temperature graphitization,carbonization and coating and the ultrahigh molecular carboxymethyl cellulose lithium-ion(CMC)was introduced as dispersant for anode slurry at the same time.Compared with the microcrystalline graphite before modification,the processability and electrochemical performance were greatly improved.The physical properties was characterized by laser particle size analyzer.The structure and surface morphology of microcrystalline graphite was analyzed by SEM.The processability of the material was characterized by the viscosity change of the sample slurry.The electrochemical properties of the samples was tested by means of coin cells.The results showed that the initial efficiency of microcrystalline graphite after graphitization increased from 64.2%to 87.1%and the ratio capacity increased from 275.2 mAh/g to 343.3 mAh/g.The anode slurry of microcrystalline graphite after coating exhibited better stability without no obvious settlement.Besides,the ratio capacity of the microcrystalline graphite after coating increased to 394 mAh/g.After the introduction of the ultra-high molecular CMC,the stability of slurry was ensured and rate performance of cell was obviously improved as a result.

关 键 词：微晶石墨 石墨化 碳包覆 超高分子CMC 

分 类 号：TQ165[化学工程—高温制品工业]