Carbon structural evolution and interfacial reaction mechanism investigation of the green anode in kneading and baking via ReaxFF-MD and force-biased Monte Carlo

Abstract

ABSTRACT Baking is the most costly and critical process in anode preparation, and the study from the microscopic scale is conducive to the optimisation of anode baking process. In this research, a hybrid simulation method of reactive force field molecular dynamics (ReaxFF-MD) and force-biased Monte Carlo (fbMC) was proposed to understand the interaction mechanism between coal tar pitch (CTP) and calcined petroleum coke (CPC) during kneading and baking processes, and to explore the optimal ratio of CTP from the molecular scale. Results showed that the CTP content of 14 wt.% was beneficial for anode production. The mechanism of anode coking behaviour at high temperatures was also analyzed. The carbonisation of CTP during high-temperature baking broke the carbon rings and formed straight chains, exposing active carbon atoms that can bond with the remaining layers. As the high-temperature simulation progresses, the carbon chains at the bonding sites became increasingly cyclized and aromatised, which made the layered structure of the baked block similar to that of graphite. The generation of various volatile hydrocarbons during the baking process was observed, namely CH4, C2H4, C2H2, C2H6, and C3H6. This work provides theoretical basis for process optimisation.