Synthesis and evaluation of petroleum-based impregnating pitch for production of high-performance artificial graphite

Abstract

The pitch impregnation process enhances the properties of synthetic graphite by optimizing their physical structure of channels and pores generated during heat treatment. Synthesizing a well-balanced molecular structure of impregnation pitch (IP) is essential for facilitating impregnation and obtaining a high carbonization yield. However, achieving this delicate balance is exceptionally challenging due to the inherent trade-off relationship between these factors. To resolve this issue, we propose a stepwise pitch synthesis recipe and the molecular weight distribution (MWD) tailoring, specifically applied to the petroleum IP from pyrolysis fuel oil (PFO). The stepwise recipe is composed of a pressurized pretreatment step applied to increase production yield and coking value, followed by a thermal polymerization step. The tailoring process is systematically designed to obtain the best performing petroleum IP by effectively removing impregnation inhibitor. Our study highlights the potential benefits of using petroleum-based pitch for impregnation processes in manufacturing of artificial graphite. The impregnation performance was enhanced by 6.7% and carbonation yield was notably improved by 16.2% relative to the coal-tar derived commercial IP. Our results show that tailoring the molecular weight distribution (MWD) of the impregnating pitch enhances impregnation performance by 1.88% compared to the raw IP.