Rapid and Up‐Scalable Flash Fabrication of Graphitic Carbon Nanocages for Robust Potassium Storage

Abstract Graphitic carbon nanocages (CNCs) have garnered attention as viable candidates for potassium storage, primarily due to their notable crystallinity, large surface area, and rich porosity. Yet, the development of a rapid, scalable, and economically feasible synthesis approach for CNCs persists as a formidable challenge. This study presents a rapid (millisecond‐scale) and scalable (gram‐scale) method for fabricating mesoporous CNCs characterized by high purity and orderly graphitic structures, utilizing the flash Joule heating technique. Employed for potassium storage, the CNC electrode developed herein exhibits exceptional performance metrics, including initial capacity, rate capability, and cycling stability, surpassing numerous carbonaceous materials previously documented. Impressively, it delivers a high initial capacity of 312.3 mAh g −1 at 0.1 A g −1 , maintains 175.1 mAh g −1 at a high rate of 2.0 A g −1 , and retains 219.6 mAh g −1 over 1000 cycles at 1.0 A g −1 . Molecular dynamics simulations and in situ characterizations are employed to elucidate this robust behavior. This work underscores the significant advantages of the flash Joule heating technique in synthesizing carbonaceous materials for potassium storage applications.