Synthesis of pitch-derived carbon anodes for high-performance potassium-ion batteries

Potassium-ion batteries (PIBs) hold promise for large-scale energy storage, necessitating the development of high-performance anode materials. Carbons with the advantage of structural versatility, are recognized as the most promising anode materials for commercialization. However, the relationship between carbon anode structure and their electrochemical performance remains unclear. Herein, a series of pitch-based soft carbons with different structures were fabricated by adjusting the carbonization temperatures in the range of 600–1400 °C, and their electrochemical K-storage performance was investigated. The variation of carbon configurations and K-storage performance in relation to the carbonization temperature was investigated. The correlation between the microcrystal size and the low-potential plateau region capacity and the correlation of the structural disordered degree of carbons with their sloping region capacity were revealed. Among all samples, MTP700 obtained by carbonization at 700 °C, has a relatively high disordered degree and larger interlayer spacing, which exhibits a high reversible capacity of 329.4 mAh g⁻¹ with a high initial coulombic efficiency of 72.81% and a maintained high capacity of 144.2 mAh g⁻¹ at the current rate of 5 C. These findings can enrich the fundamental understanding of the K-storage process in carbon anodes, and thus facilitate the advancement of PIBs.