Electrostatically Engineered CNT and Cross‐Linked PEDOT:PSS on Mulberry Paper–Based Flexible Supercapacitor for High Electrochemical Performance and Reliability

The growing demand for flexible and wearable energy storage systems calls for sustainable and mechanically robust substrates that overcome the limitations of conventional rigid and nonbiocompatible materials. Here, we present a binder‐free and flexible supercapacitor fabricated on mulberry paper, integrating electrostatically engineered carbon nanotubes (CNTs) and covalently cross‐linked poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). CNTs modified with a cationic surfactant, cetyltrimethylammonium bromide (CTAB), uniformly adhere to the hydroxyl‐rich fibers via electrostatic interactions, enhancing interfacial stability and minimizing resistance. PEDOT:PSS is cross‐linked using divinyl sulfone (DVS), simultaneously improving electrical conductivity and aqueous stability. The resulting device exhibits an areal capacitance of 30.4 mF cm −2 at 50 mV s −1 and maintains 95.9% of its capacitance over 80,000 cycles at 4.0 mA cm −2 . This study provides a scalable and low‐cost platform for high‐performance, durable, and flexible energy storage, highlighting a novel interfacial engineering strategy for natural fiber substrates.