Mussel-Inspired Conductive Hydrogel with Enhanced Adhesion and Toughness in All-Hydrogel Supercapacitors

Graphical A tannic acid-rich polyaniline conductive hydrogel with good adhesion as well as tensile properties (elongation at break of 903 %) was prepared by a simple in situ polymerization method, the assembled flexible supercapacitors exhibited tough interfacial contact properties, and provided a volume capacitance of 570 mF cm −3 . Hydrogels that combine electrical conductivity, mechanical and self-adhesion properties have attracted considerable interest because of their promising applications in wearable devices and flexible supercapacitors, among others. However, the weak interfacial adhesion between adjacent layers of flexible supercapacitors limits their practical applications. In this work, mussel-inspired nanocomposite hydrogels composed of tannic acid (TA)-modified doped polyaniline (PANI) and functional monomer acrylamide (AAm) were prepared, the hydrogel exhibited good mechanical properties (903 % strain at break) and adhesion properties. In a three-electrode system the hydrogel exhibited a specific capacitance of 851.1 mF cm −2 (at 1 mA cm −2 ) and good stability. All-hydrogel supercapacitors with robust interfacial capabilities were assembled on this basis without additional immobilization. The flexible supercapacitors show favorable electrochemical performance (570 mF cm −3 at 1 mA cm −2 ) and provide a volume energy density 55.9 μWh cm −3 and a capacitance retention of 85.6 % after 2000 cycles. Compared with previous conductive hydrogels, this work will provide a new approach to fabricate nanocomposite hydrogels with self-adhesive, robust mechanical properties and conductive performance, effectively improving the interfacial adhesion of integrated supercapacitors and expanding the application scope of flexible supercapacitors.