近年来,煤系沥青衍生碳材料因其结构可调和导电性高等特点,被广泛应用于钾离子电池负极材料。然而,煤沥青分子结构与组成复杂多样,不同沥青分子间的结构差异会影响沥青衍生碳材料的结构和电化学性能,精确控制碳材料微观结构颇具挑战,特别是煤沥青族组分与其衍生碳材料储钾性能间的构效关系仍不明晰。因此,迫切需要充分了解沥青的组成和结构特征,考察煤沥青原料组成对其衍生碳微观结构与储钾性能的影响。本研究采用溶剂分级萃取技术对煤沥青进行族组分分离,成功分离出甲苯可溶物(TS)、甲苯不溶-喹啉可溶物(TI-QS)和喹啉不溶物(QI)。TS在800℃时的衍生碳材料(TS-800)主要以插层储钾为主,受限于较少的存储位点和较低的碳层间距,其容量和循环稳定性均较差;TI-QS-800由于插层和吸附储钾共同作用,在低电流密度下容量相对较高(333mAhg−1),但在大电流下倍率性能明显降低;QI-800具有较大的层间距和无序度,有利于钾离子的快速迁移,大电流密度下的倍率性能最佳,循环性能相对更优。本文不仅为煤沥青基碳材料的设计和制备提供了新的思路,也为钾离子电池负极材料的开发提供了重要的实验数据和理论支持。

Recently,coal tar pitch-derived carbon materials have been widely used as anode materials for potassium-ion batteries due totheir adjustable structure and high conductivity. However,the molecular structure and composition of coal tar pitch are complex anddiverse,and the structural differences between different pitch components may affect the structure and electrochemical performance.Precise control over the microstructure of carbon materials is quite challenging,especially the relationship between the structuralproperties of coal tar pitch components and the potassium storage performance of their derived carbon is still unclear. Therefore,it isurgent to fully understand the composition and structural characteristics of the pitch,and investigate the impact of pitch composition onthe formation of carbon microstructure and potassium storage performance. This work used solvent extraction technology to fractionatecoal tar pitch,successfully separating toluene-soluble (TS),toluene insoluble-quinoline soluble (TI-QS) and quinoline insoluble(QI) component. The TS-derived carbon materials (TS-800) is primarily dominated by intercalation potassium storage. However,due to the limited number of storage sites and reduced spacing between carbon layers,it exhibits poor capacity and cycling stability. TI-QS-800,due to the combination of intercalation and adsorption potassium storage,has a relatively higher capacity at low current density(333 mAh g),but its rate performance significantly decreases under high current densities. QI-800 has a larger layer spacing anddisorder degree,which is beneficial for rapid migration of potassium ions,and has the best rate performance,with relatively better cyclingperformance. This work not only provides new insights into the design and preparation of coal tar pitch-based carbon materials,but also offers important experimental data and theoretical support for the development of anode materials for potassium-ion batteries.