【作者】 宁林坚； 王玲治； 方世璧；

【Author】 L.J. Ning, L.Z. Wang, S.B. Fang Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China

【机构】 中国科学研究院化学研究所；

【摘要】 为改善天然石墨的性能,通过浸渍的方法在石墨的表面上包覆不同厚度的聚硅氧烷,然后在Ar气保护下于800℃炭化3h制得改性石墨材料。应用电子扫描显微镜(SEM)及恒电流充放电技术研究改性石墨材料的表面物理形态及在不同电流密度下的充放电性能。结果表明包覆在石墨表面的聚硅氧烷热解碳提高了复合材料的可逆容量,减少了在首次锂嵌入过程中所发生的不可逆反应,有效抑制了石墨在循环过程中发生的层状剥落,同时改善了锂离子嵌入的动力学过程,提高了大电流性能。更多还原

【Abstract】 To improve the graphite performance, the natural graphite was coated with polysiloxane by immersion method. The coated graphite was carbonized at 800℃ for 3h with Ar protection. The surface morphology and charge/discharge properties of the modified graphite were investigated by means of SEM and constant-current charge/discharge technology. The results show that the coating of pyrolytic carbon on the surface of graphite can increase the reversible capacity of composite electrode and reduce the initial irreversible capacity. Modified graphite is prevented from the lamellar exfoliation during the proceeding cycle by the pyrolytic carbon coated on the graphite surface. The lithium ion intercalation kinetic was improved. Cyclability and rate-capability of these modified graphite electrode are much better than those of bare graphite electrode.更多还原