A High‐Performance Flexible All‐Solid‐State Supercapacitor Integrating 3D Interpenetrating MXene/GNS@CC Electrodes and a Self‐Healing Hydrogel Electrolyte

ABSTRACT This work presents a flexible, self‐healing supercapacitor (SHSC) comprising an MXene/graphene nanoscrolls@carbon cloth (MXene/GNS@CC) composite electrode and a self‐healing poly(vinyl alcohol)‐polydopamine (PVA‐PDA) hydrogel electrolyte. The MXene/GNS@CC electrode was directly fabricated on carbon cloth through a one‐step electrophoretic deposition (EPD) strategy, in which graphene nanoscrolls (GNS) were interwoven among the MXene nanosheets to construct a three‐dimensional (3D) interpenetrating architecture. This architecture suppressed nanosheet restacking, increased accessible surface area, facilitated ion transport, and improved mechanical reliability. The resulting electrode was further integrated with a self‐healingPVA‐PDA hydrogel electrolyte to assemble an all‐in‐one supercapacitor. Owing to the abundant catechol groups in PDA, the hydrogel electrolyte exhibited excellent self‐healing capability and strong interfacial adhesion. Moreover, hydrogen‐bonding interactions with the terminal groups on the MXene surface and π – π conjugation interactions with GNS contributed to the formation of a robust 3D network. Consequently, the MXene/GNS@CC electrode delivered an areal capacitance of 6880.60 mF·cm −2 at 1 mA·cm −2 . The assembled SHSC achieved an areal capacitance of 1152.03 mF·cm −2 at 1 mA·cm −2 and an areal energy density of 195.37 µWh·cm −2 at a power density of 0.61 mW·cm −2 . Additionally, the device retained 87.32% of its initial capacitance even after four cutting/healing cycles, indicating its broad application prospects in the field of flexible self‐healing energy‐storage devices.