Abstract: Oxidative cross-linking treatment of mesophase pitch can endow it with excellent electrochemical properties, enabling its use in the production of high-performance carbon materials. Mesophase pitch was prepared from the aromatic-rich fraction of FCC slurry and oxidized at different temperatures. Scanning electron microscope,fourier transform infrared spectroscopy,X-ray diffraction spectroscopy,and thermogravimetric analyzer were used to analyze the microstructure,functional groups, crystal structure,and thermal stability of the mesophase pitch before and after oxidation,respectively. The effect of the oxidation process on the structural properties of the mesophase pitch was investigated. The results showed that the thermal stability of the mesophase pitch significantly improved after oxidation treatment. When the oxidation temperature was 130 ℃ or below, the primary reactions occurring in the system were the removal of aliphatic groups and the ring-opening reactions of aromatic hydrocarbons, accompanied by an increase in the small aromatic molecular lamellar structures. The lowest interlayer spacing in the system was 0.3440 nm, indicating the most compact structure, while the orderliness between molecular layers decreased. When the oxidation temperature was 160 ℃ or above, oxidative cross-linking reactions dominated in the system. Compared to the case at an oxidation temperature of 130 ℃, the aromaticity of the system decreased, while the stacking height and orderliness of the molecular lamellae increased, and a large number of micro-globular mesophase pitch structures emerged in the microstructure.

Key words: mesophase pitch, oxidation cross-linking, FCC slurry, orderliness, crystal structure, lithium-ion battery, anode material