Mechanisms and implications of the novel CAST model of coal graphitization

Objective and Methods  Coal graphitization is a multi-stage process with abrupt changes rather than linear evolution. So far, its inherent driving mechanisms have not yet been fully elucidated. Notably, twisted graphene was observed in the process of coal graphitization in 2025, providing a new opportunity to reveal the essence of this structural transformation.

Results and Conclusions  By combining previous research results, this study proposes a novel coal graphitization model that consists of condensation, alignment, stacking, and twisting (CAST). The four parts of the CAST model are organically integrated, collectively forming a continuous and dynamic evolutionary process. Most especially, no absolute boundaries exist among alignment, stacking, and twisting; instead, the three processes interact manually, jointly controlling and adjusting the progress and degree of coal graphitization. Theoretically, the novel CAST model clarifies the fundamental nature of coal graphitization as evolution from short-range disorder into long-range order. Therefore, this model provides a new perspective for gaining deep insights into the coal graphitization process and even enables the reconstruction of the underlying mechanisms of coalification. Practically, this novel model can direct the research focus toward the performance of coal as raw materials rather than merely as fuels, thus maximizing its value as "black gold".