An electrode universal and self-healable integrated supercapacitor fabricated by physical adsorption based on mussel-inspired highly adhesive gel electrolyte

Integrated supercapacitor with stable electrochemical performance under complex deformations is the prospective energy storage device for wearable electronics. However, there is often a conflict between the mechanical performance and the specific capacitance of the conventional conductive polymer-based integrated supercapacitor. In this work, a novel integrated supercapacitor based on adhesive gel electrolyte has been prepared by physical adsorption, which not only avoids the drawbacks of the conventional integrated supercapacitor but also exhibits the electrode universality including powder electrode material. The adhesive triple network polyacrylamide/polydopamine/agar/H 3 PO 4 gel electrolyte is fabricated with high ionic conductivity, toughness and adhesion. Based on this, the integrated supercapacitor is assembled by spraying activated carbon powder on both sides of the pre-stretched biaxially gel electrolyte. Due to the strong interfacial adhesion, such a device exhibits low interfacial resistance and high specific capacitance of 155 mF/cm 2 at 0.5 mA/cm 2 . More impressively, the capacitance retention can reach 92.4% after 10 cutting/healing cycles and even keep the brilliant self-healabillity at −20 °C. Additionally, it can hold stable electrochemical performance when exposed to harsh environments. The physical adsorption strategy would offer novel inspiration for the development of integrated supercapacitor and has great practical applications in wearable and portable electronics.