磺化沥青包覆石墨用作锂离子电池负极材料

Sulfonated pitch coating graphite for anode of lithium ion batteries

以水溶性磺化沥青为包覆材料,在其水溶液中完成了对天然鳞片石墨的表面包覆,复合材料制备条件温和,避免了有机溶剂的使用。通过XRD、SEM和TEM对复合材料的形貌结构进行表征,并研究了复合材料的电化学性能。结果表明,天然鳞片石墨边缘尖锐的棱角和不规则的缺陷被一层无定形炭覆盖,复合材料的首次充放电效率和循环稳定性显著提高。复合材料首次放电比容量为351.8mAh/g,首次效率达到91.9%,40次循环后容量没有出现明显衰减,容量保持率为99.6%。

Natural flake graphite powder was coated by sulfonated pitch in aqueous solutions. The preparation condition is mild, avoiding using organic solvent. XRD, SEM and TEM were used to characterize the morphology and structure. The results show that the surface defects and edge sites of original graphite are uniformly covered by the amorphous carbon layer. Electrochemical measurements were then carried out to evaluate the anode performances. The modified graphite shows an initial efficiency up to 91.9% and discharge specific capacity of 351.8 mAh/g. Meanwhile, its capacity remains as high as 99.6% of initial discharge capacity after 40 cycles charge/discharge tests, evincing good cycle performance.