Engineering Mesoporous Structure in Amorphous Carbon Boosts Potassium Storage with High Initial Coulombic Efficiency

Highlights A facile self-etching strategy was used to obtain mesoporous carbon (meso-C) nanowires with zinc-catalyzed short-range ordered structure. Meso-C anode showed high initial Coulombic efficiency (76.7%) and excellent cycling stability (1000 cycles) for potassium-ion batteries. In/ex situ characterizations revealed the reversible structural changes, and the kinetic analyses revealed the rapid K + diffusion in electrode. Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries; however, its abundant defects or micropores generally capture K ions, thus resulting in high irreversible capacity with low initial Coulombic efficiency (ICE) and limited practical application. Herein, pore engineering via a facile self-etching strategy is applied to achieve mesoporous carbon (meso-C) nanowires with interconnected framework. Abundant and evenly distributed mesopores could provide short K + pathways for its rapid diffusion. Compared to microporous carbon with highly disordered structure, the meso-C with Zn-catalyzed short-range ordered structure enables more K + to reversibly intercalate into the graphitic layers. Consequently, the meso-C shows an increased capacity by ~ 100 mAh g −1 at 0.1 A g −1 , and the capacity retention is 70.7% after 1000 cycles at 1 A g −1 . Multiple in/ex situ characterizations reveal the reversible structural changes during the charging/discharging process. Particularly, benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less defects, the meso-C generates less irreversible capacity with high ICE up to 76.7%, one of the best reported values so far. This work provides a new perspective that mesopores engineering can effectively accelerate K + diffusion and enhance K + adsorption/intercalation storage.