石油焦锂离子电池负极材料电化学性能研究

Study on electrochemical performance of petroleum coke lithium-ion battery anode materials

负极材料是决定锂离子电池性能的关键因素,人造石墨是重要的锂离子电池负极材料。石油焦的热膨胀系数低,空隙度低,灰分、硫、金属元素含量低,导电率高,易石墨化。此次研究选择3种普通石油焦,并通过石墨化制备人造石墨。对3种石油焦原样和石墨化样品进行分析表征,比较其各种性能,研究石油焦石墨化后的变化,并通过电化学分析验证石油焦石墨化后其性能是否达到商用锂电池负极材料水平。实验结果表明:在2750℃石墨化处理后,相较于原石油焦样品,3种石墨化样品结构重排,拥有更明显的规整层状结构;含碳量提升,其他例如氢、氧等杂元素和金属元素含量下降;均显现出较低的电极电位和稳定的充放电平台,首次库伦效率分别为85.00%、78.20%、82.96%。经过150次循环后,比容量分别保持在273.00、259.00、226.20 mAh/g,库伦效率接近100%,是锂离子电池负极材料的潜在前驱体。

The quality of anode material is the key factor determining the performance of lithium-ion batteries.Artificial graphite is an important anode material for lithium-ion batteries.Petroleum coke has low thermal expansion coefficient,low porosity,low impurity content,high conductivity and easy graphitization.This study selects three types of common petroleum coke,and prepares artificial graphite by graphitization.Analyze and characterize three types of original petroleum coke samples and three types of graphitized samples,study the changes of petroleum coke after graphitization,and verify whether the performance of petroleum coke after graphitization reaches the level of commercial lithium battery anode materials through electrochemical analysis.The experimental results show that after graphitization treatment at 2,750℃,compared with the original petroleum coke sample,the graphitized samples rearrange their structures and have a more obvious regular layered structure;the carbon content increases,and the content of other miscellaneous elements such as H and O and metal elements decreases;all show lower electrode potential and stable charge-discharge platform,with the initial coulombic efficiency of 85.00%,78.20%and 82.96%,respectively.After 150 cycles,the mass specific capacities are maintained at 273.00,259.00 and 226.20 mAh/g,respectively,and the coulombic efficiency is close to 100%,which is a potential precursor of lithium-ion battery anode materials.