Fully Recyclable All‐Solid‐State Supercapacitors with High Stretching Stability and Room‐Temperature Self‐Healing Capability

Abstract Fully recyclable all‐solid‐state supercapacitors (ASSCs) that are highly stretchable and self‐healable are ideal for next‐generation wearable electronics but remain underexplored. Here, a fully recyclable ASSC is developed by integrating elastic electrodes and solid‐state electrolytes derived from reversibly cross‐linked polymers. The elastic electrodes, composed of polyurethane (PU) elastomers and MXene‐carbon nanotube (MX‐CNT) hybrids (denoted as PU/MX‐CNT), exhibit high stretchability, conductivity, and mechanical robustness. The solid‐state hydrogel electrolyte, composed of KCl‐loaded polyvinyl alcohol (PVA) derivatives cross‐linked by reversible borate ester bonds, exhibits strong interfacial adhesion with PU/MX‐CNT electrodes. The resulting ASSCs, fabricated by sandwiching the PVA electrolyte between two PU/MX‐CNT electrodes, deliver a high areal capacitance of 643 mF cm −2 and a Coulombic efficiency of 89.8%. They also exhibit excellent mechanical and electrochemical stability, retaining 96.1% of original capacitance after 12 000 charge‐discharge cycles and 91.7% after 1200 stretching cycles at 100% strain. Notably, the ASSCs demonstrate rapid self‐healing at room temperature and can be fully disassembled in selective solvents to recover PU, MX‐CNT, and PVA electrolytes with high yields and purities. The refabricated ASSCs exhibit electrochemical performance nearly identical to the pristine devices. This work presents a practically useful strategy for fabricating high‐performance, recyclable ASSCs, advancing the development of sustainable energy storage.