Lamellar Oxygen-Enriched Graphene Hydrogel with Linking-up Network Porous Structure for High-Performance Supercapacitors

Abstract

Here, we report a lamellar holey oxygen-enriched graphene hydrogel (LGH) consisting of graphene sheets with a large amount of oxygen functional groups and in-plane pores and confirm its excellent supercapacitive performances. LGH is quite different from the traditional graphene hydrogel in terms of both the morphology and porous structure. Importantly, the in-plane pores on the graphene sheets link up the out-of-plane interval between the graphene sheets to form a linking-up network porous structure. The in-plane pores result in more micropores and the additional oxygen functional groups on graphene sheets. The LGH single electrode exhibits an ultrahigh capacitance (337.8 F g–1 at 1 A g–1) and excellent rate capability (the specific capacitance at 100 A g–1 retains 77% relative to 1 A g–1). The asymmetric supercapacitor is assembled by using the LGH as positive electrode material and the graphene hydrogel that has adsorbed anthraquinone as negative electrode material, respectively. The device exhibits a h...