Ultrafast Manufacturing of Ultrafine Structure to Achieve An Energy Density of Over 120 Wh kg(-1) in Supercapacitors

Supercapacitor (SC) is one of the most promising electrochemical energy-storage devices. However, the practical application of SCs is limited by the low-energy density. Herein, high-temperature shock (HTS)-derived ultrafine structure-activated porous carbon (UAPC) with N, O functional groups is reported as high-energy density SCs carbon. The process of ultrafast joule heating and cooling effectively transfers general-purposed carbon into electrochemical-activated carbon. The UAPC-based SCs exhibit an energy density of up to 129 Wh kg(-1) in EMIMBF4 ionic liquid, which outperform almost all reported and commercial SCs (22 Wh kg(-1)). The outstanding electrochemical performance of UAPC is attributed to the ultrafine structure and N, O functional groups, which enlarges the surface area, improves the surface wettability of UAPC electrodes, and provides pseudocapacitance. The facile and efficient ultrafast-processing strategy has opened up an unprecedented pathway for the application of low-value carbon for the electrode design and application of SCs.