不同沥青改性硬碳材料的性能

Performance of different asphalt modified hard carbon materials

沥青基热解软碳具有良好的导电性和电解液相容性,是改善硬碳材料首次库仑效率低、循环性能差的理想材料。以组分不同的石油沥青和煤沥青作为软碳前驱体,采用微波加热法分别制备改性软/硬碳复合负极材料P@HC和C@HC。热重(TG)分析、SEM和电化学测试的结果表明,含有高不溶物(甲苯不溶物、喹啉不溶物)组分的煤沥青热解过程更平缓,残碳率更高,热解后形成的软碳均匀且致密地附着在硬碳表面,形成煤沥青热解软碳复合硬碳材料(C@HC)。在0.01~2.50 V充放电,C@HC样品的首次库仑效率提升至74.5%,在20.0 C倍率下的放电比容量达130 mAh/g,较纯硬碳材料有显著提升,1.0 C循环200次后的容量保持率从83.5%提升至91.5%以上。

Pitch based pyrolytic soft carbon had good electrical conductivity and electrolyte compatibility,making it an ideal material for improving the low initial Coulombic efficiency and poor cycle performance of hard carbon materials.The modified soft/hard carbon composite anode materials P@HC and C@HC were prepared by microwave heating using two different components of petroleum asphalt and coal tar pitch as soft carbon precursors.The analysis results of thermogravimetric(TG)analysis,SEM and electrochemical tests indicated that the pyrolysis process of coal tar pitch containing highly insoluble components(toluene insoluble,quinoline insoluble)was smoother,with a higher carbon residue rate.The soft carbon formed after pyrolysis was uniformly and tightly adhered to the surface of hard carbon,forming a coal tar pitch pyrolysis soft carbon composite hard carbon material(C@HC).When charged-discharged in 0.01-2.50 V,the initial Coulombic efficiency of the C@HC was increased to 74.5%,the specific discharge capacity reached 130 mAh/g at a rate of 20.0 C,significantly improving compared to pure hard carbon materials,after 200 cycles at 1.0 C,the capacity retention rate increased from 83.5%to more than 91.5%.