Preparation of Mesocarbon Microbeads (MCMBs) by the Copolycondensation of High-Temperature Coal Tar Pitch and Ethylene Tar Pitch

Mesocarbon microbeads (MCMBs) are a kind of typical spherical functional synthetic carbon materials widely used in various fields. However, MCMBs produced through thermal polycondensation using high coal tar pitch exhibit certain defects that limit their further development. These include challenges in controlling particle size, low yield, and difficulties in regulating their internal microstructure and surface morphology. In this study, MCMBs were prepared via the copolycondensation of high-temperature coal tar pitch (HCTP) and ethylene tar pitch (ETP). The effect of ETP addition on the formation process, microstructure, and electrochemical properties of the resulting MCMBs was investigated. Polarizing microscopy, scanning electron microscopy (SEM), laser particle size analysis, single-crystal X-ray diffraction (XRD), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) were employed to analyze the MCMBs. The addition of ETP was found to modify the molecular structure of the blended pitch and promote the formation of MCMBs during the copolymerization process. Furthermore, the MCMBs obtained via this method exhibited excellent sphericity, uniform particle size distribution, reduced structural defects, and lower charge transfer resistance (R_ct). Notably, when the ETP content was 7%, the MCMBs achieved an average particle size of 19.65 μm, a particle size uniformity index (U) of 1.12, and the lowest charge transfer resistance of 2.947 Ω after carbonization.