沥青焦在煅烧过程中的微观结构演变及电化学性能研究OA北大核心

As a key functional carbon material,the microstructural characteristics of pitch coke directly determine the physicochemical properties and application performance of the final product.Systematically studying the evolution process of the microstructure of pitch coke during the calcination process and the relationship between microstructure and macroscopic properties is of great significance for the high-value utilization of pitch coke.In this study,three types of pitch cokes with different optical microstructures(XQ,XW,GY)were calcined at various temperatures(600-1400℃),and the differences in the micro-morphology,carbon microcrystal structure,and other characteristics of the coke samples were investigated using polarized light microscopy,SEM,XRD,and Raman spectroscopy.The three kinds of pitch cokes calcined at 1400 ℃ were applied in the lithium-ion battery cathode materials to evaluate their electrochemical performance,respectively.The results show that the calcination temperature significantly influences the ordering process of the pitch coke's microstructure.As the temperature increases,the degree of anisotropy of the pitch coke gradually improves,and the orientation of the carbon layers increases.The ordered needle-like structures in the XW series coke samples effectively reduce the volume expansion during calcination,demonstrating a high true density and a low powder resistivity.A mosaic structure significantly enhances the micro-strength of the XQ series coke materials.The XW-1400 demonstrates an excellent initial Coulombic efficiency(72.5％)and a reversible capacity(384.15 mAh/g)in the lithium-ion battery anode materials.Therefore,by regulating the initial optical structure of the green coke and the parameters of the calcination process,it is possible to effectively optimize the microstructural features of the pitch coke,thereby achieving precise control over its macroscopic performance.