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.