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

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.