Mechanically robust double-crosslink network functionalized graphene/polyaniline stiff hydrogels for superior performance supercapacitors
Abstract
To extend the applications of supercapacitors, it is important and challenging to develop structural/stiff supercapacitors with excellent mechanical and electrochemical performance. In this work, high performance double-crosslink network functionalized graphene/polyaniline stiff hydrogels (DN-PGH/PANIPA) have been successfully synthesized by polymerization of aniline in confined functionalized graphene (PGH) hydrogel framework. Unique polyaniline (PANI) morphology with a combination of nanodot protrusion and nanofiber is obtained, where nanodot protrusions are tightly anchored to graphene walls and nanofibers crosslink graphene sheets. As-prepared DN-PGH/PANIPA hydrogel, consisting of continuous conductive closely combined double-crosslink network, PANI nanofibers and high crystalline degree of PANI structure, is both stiff and mechanically robust with high tensile strength of 1.39 MPa at small ruptured elongation of 0.42%. Meanwhile, DN-PGH/PANIPA stiff hydrogels are assembled into symmetric supercapacitors and achieve superior areal specific capacitance of 3488.3 mF cm-2 and volumetric specific capacitance of 872 F cm-3, remarkable rate capability, and excellent cycling stability, resulting in notable energy density of 155 μWh cm-2 at 200 μW cm-2 and outstanding power density of 20015 μW cm-2 at 67.5 μWh cm-2. This novel double-crosslink network design strategy establishes a promising approach towards the development of other stiff electrode materials as high performance structure supercapacitors.
