One-step synthesis of polyhydroquinone–graphene hydrogel composites for high performance supercapacitors

Abstract

Electroactive polymers constitute an important class of electrode materials for supercapacitors based on pseudocapacitance. However, it is difficult to utilize low-conductive electroactive polymers in supercapacitors, although these polymers may have large theoretical specific capacitance. In this article, we designed and prepared a novel type of electrode material, with a unique structure of low-conductive electroactive polyhydroquinone (PHQ) coated on a highly conductive three-dimensional (3D) porous graphene hydrogel (GHG). PHQ–GHG composites were prepared via a one-step reaction between graphene oxide and hydroquinone under mild conditions. Because PHQ has a large theoretical specific capacitance, and GHG possesses a 3D porous structure, large specific surface area and high electrical conductivity, the composites showed a high specific capacitance of 490 F g⁻¹ at a current density of 24 A g⁻¹, as well as excellent rate performance and cycling stability. These results demonstrate that PHQ–GHG composites are promising electrode materials for supercapacitors, and the method developed in this paper paves a new way for utilizing those electroactive polymers of low electrical conductivities in supercapacitors.