Simple synthesis of pitch-derived carbon anode 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. Carbon with the advantage of structural versatility, is 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 carbon materials with different structures are fabricated by adjusting the carbonization temperatures at the range of 600–1400 °C, and their electrochemical K-storage performance has been systematically investigated. Among all, MTP700, with a relatively high disordered degree and larger interlayer spacing, 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. The study investigated the variation of carbon configurations and K-storage performances in relation to carbonization temperature, elucidating the correlation between the microcrystal size and the low-potential plateau region capacity as well as the structural disordered degree with the sloping region capacity. These findings can enrich the fundamental understanding of the K-storage process in carbon anodes, and thus facilitate the advancement of PIBs.