Interlayer-expanded carbon anodes with exceptional rates and long-term cycling via kinetically decoupled carbonization

ZH Cheng and H Zhang and JF Cui and JL Zhao and S Dai and ZX Zhang and KC Song and SY Wang and YK Yuan and QL Chen and XQ Kong and L Qie and LX Yuan and HP Yang and SZ Zhu and YJ Fang and YH Huang and YG Yao, JOULE, 9, 101812 (2025).

DOI: 10.1016/j.joule.2024.101812

Conventional carbonization is often energy-intensive, time consuming, and characterized by tightly coupled sub-processes that yield hard-to- control structures and compromised performance. This study introduces a kinetically decoupled carbonization strategy tailored for carbon anodes in sodium-ion batteries. The process involves a pyrolysis (700 degrees C, 1 h) followed by rapid high-temperature heating (1,950 degrees C, 22 s), enabling efficient impurity removal and swift carbon crystallization with minimal graphitization, alongside an '80% energy reduction. The obtained expanded carbon (EC) exhibits larger grain sizes and expanded interlayer, rendering higher capacity, exceptional rate, and long-term stability (>6,000 cycles at a current rate of 10 C) than current carbon anodes. Mechanistic investigations reveal a wide intercalation potential range (2-0.01 V) in EC without inducing detrimental sodium clustering, thereby supporting expanded layers and easy intercalation for high capacity, fast charging, and robust stability. Our strategy provides a precise, energy-efficient pathway to develop desirable carbonaceous materials for batteries and advanced applications.

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