Triple-Dynamic-Bond-Engineered Self-Healing Conductive Hydrogels for Deformation-Immune Flexible Supercapacitors and Wearable Epidermal Sensors

Conductive hydrogels are promising for flexible electronics, yet integrating high conductivity, mechanical robustness, biocompatibility, and environmental stability for flexible supercapacitors (FSCs) and wearable epidermal sensors remains challenging. Herein, a self-healing hydrogel with multiple energy dissipation pathways was constructed using synergistic dynamic borate ester bonds, Schiff base bonds, and hydrogen bonds. Incorporating polydopamine-coated MXene (MP) enhanced the mechanical strength, conductivity, and antibacterial/antioxidant properties. FSCs with the hydrogel electrolyte exhibited excellent electrochemical performance with a specific capacitance of 373.41 mF/cm2, an energy density of 74.67 μWh/cm2, a capacitance retention of 82.43% after 5000 cycles, and high deformation tolerance. As a strain sensor, it effectively detected both large and subtle human motions, including physiological microexpressions and pulse beats due to its high sensitivity (gauge factor = 1.73) and repeatability. Importantly, its notable degradability owing to the inherent degradability of the chitosan framework and the reversible dissociation of dynamic bonds addresses environmental concerns from traditional electronics.