Scaleup Sodium‐Ion Capacitor Ah‐Level Pouch Cells Enable 100 C Ultrafast Charging Capabilities

Abstract Traditional hybrid ion capacitors face the low capacity of electric double‐layer (EDL) storage in narrow potential windows and the requirement of prelithiation (or presodiation) for practical device fabrication. Herein, we demonstrate that the activated carbon negative electrode (AC NE) maintains EDL capacitive behavior without the influence of solid electrolyte interphase (SEI) layers in a wide potential window of 3–0.05 V vs. Na + /Na. Remarkably, the AC NE displays an ultrahigh EDL capacitive storage capacity of 145 mAh g −1 (177 F g −1 ), a high initial coulombic efficiency of 95.6%, capacitor‐level ultrahigh rate capabilities and excellent cycling stability. Importantly, we assemble a 1.6 Ah (1694 F) SIC pouch cell, which delivers a high energy density of 42 Wh kg cell −1 (based on the total mass of the device), a high state of charge (SoC) of 57% at an ultrafast charging rate of 100 C, stable 10000 electrochemical cycles and high safety (passing nailing penetration and thermal runaway tests). Additionally, the high‐performance SIC is assembled without any presodiation treatment, which largely reduces manufacturing complexities and costs. Our work provides a significant milestone for the ultimate goal of electrochemical capacitors, which is increasing the energy density accompanied by capacitor‐level high power density, long‐term cyclability, and easy assembly.