Constructing Biomass‐Derived Ultra‐Thin 2D Carbon Nanoweb via Confinement‐Driven Bubbling Effect for High‐Rate Zinc‐Ion Storage in Hybrid Capacitors

ABSTRACT Two‐dimensional (2D) carbon materials demonstrate significant potential for energy storage. However, interlayer stacking in high‐mass‐loading electrodes of lamellar 2D carbon materials typically leads to discontinuous interlayer channels, increasing ion diffusion tortuosity. Herein, an ultra‐thin 2D carbon nanoweb was fabricated via a confinement‐driven bubbling effect, enabling high reversible capacity and fast ion transport at high charge‐discharge rates and in high‐mass‐loading electrodes. In situ monitoring of gas and solid products demonstrated that pyrolysis products were confined within the confined space to form ultra‐thin (1.5–2.5 nm) 2D structures with a high graphitization degree. Meanwhile, the bubbling activation within liquid molten salt constructed nanoweb structures with a high specific surface area (2055 m 2 g −1 ). The assembled zinc‐ion hybrid capacitors (ZIHCs) exhibited exceptional rate performance (229 mAh g −1 at 0.1 A g −1 and 117 mAh g −1 at 10 A g −1 ) and cycle stability (97.34% capacity retention after 20,000 cycles at 10 A g −1 ). Combined ex situ spectroscopic characterizations, kinetic analyses, and theoretical calculations revealed that the ultra‐thin 2D carbon nanoweb reduced ion transport resistance and polarization. At a power density of 97.18 W kg −1 , ZIHCs achieved a high energy density of 187.20 Wh kg −1 , surpassing most previously reported carbon materials.