Preparation of disordered carbon for alkali metal-ion (Lithium, Sodium, and Potassium) batteries by pitch molecular modification: A review

Pitch-based carbon materials are deemed promising anodes in electrochemical energy storage due to their cost-effectiveness, excellent electrical conductivity, and considerable carbon content. However, the direct pyrolysis pitch undergoing an uncontrollable liquid phase carbonization forms microstructures with small interlayer spacing and high orientation, which leads to poor rate performance for alkali metal-ion (Lithium, Sodium, and Potassium) batteries (AMIBs). At present, the structure regulation of pitch-based carbon materials is limited to the optimization of preparation processes and the addition of templates. It has been found that the molecular structure of pitch plays an important role in the microstructure and electrochemical performance of as-prepared carbon materials, while there has been no recent review of the numerous studies of reaction mechanisms of pitch molecular structure modification. Therefore, this paper presents a comprehensive review that summarizes the molecular structure modification mechanism of pitch-based disordered carbon materials (PDCs)-related research. Moreover, the influence of reaction mechanisms on the microstructure, morphology, and electrochemical performance of as-prepared carbon products is discussed. Finally, the substantial limitations and challenges to promoting further research and development were emphasized. This comprehensive review might provide targeted guidance for the design and preparation of high-performance AMIB anode materials. The modification strategies of molecular structure are the selection of fractions and precursors, molecular structure modification by free radical reactions, molecular structure modification by electrophilic aromatic reactions, and pitch co-carbonization with highly reactive hydrocarbon compounds. [Display omitted] •Summarized the molecular structure modification mechanism of pitch for preparation of PDCs.