A Self-Healing Crease-Free Supramolecular All-Polymer Supercapacitor

Abstract

While traditional three-layer structure supercapacitors are under mechanical manipulations, the high-stress region concentrates, inevitably causing persistent structural problems including interlayer slippage, crease formation, and delamination of the electrode–electrolyte interface. Toward this, an all-polymeric, all-elastic and non-laminated supercapacitor with high mechanical reliability and excellent electrochemical performance is developed. Specifically, a polypyrrole electrode layer is in situ integrated into a silk fibroin-based elastic supramolecular hydrogel film with extensive hydrogen and covalent bonds, where a non-laminate device is realized with structural elasticity at the device level. The non-laminate configuration can avoid slippage and delamination, while the elasticity can preclude crease formation. Furthermore, under more severe mechanical damage, the supercapacitors can restore the electrochemical performance through non-autonomous self-healing capabilities, where the supramolecular design of host–guest interactions in the hydrogel matrix results in a superior self-healing efficiency approaching ≈95.8% even after 30 cutting/healing cycles. The all-elastic supercapacitor delivers an areal capacitance of 0.37 F cm⁻² and a volumetric energy density of 0.082 mW h cm⁻³, which can well-maintain the specific capacitance even at −20 °C with over 85.2% retention after five cut/healing cycles.