High-Surface-Area Graphene Oxide for Next-Generation Energy Storage Applications

Abstract

Synthesis of high-surface-area graphene oxide for application in next-generation devices is still challenging. In this study, we present a simple and green-chemistry procedure for the synthesis of oxygen-enriched graphene materials, having very large surface areas compared with those reported for powdered graphene-related solids. Using the hydrothermal treatment of carbon nanohorns by a green-chemistry H2O2 oxidant under elevated pressure, the progressive creation of a stable carbon nanomaterial, denoted as open-sensu-shaped graphene oxide (OSSGO) by us, is observed. This oxygen-enriched nanographene contains π–π stacked few-layered graphene ribbons curved at the termini derived from the original cone tip. OSSGO is intensively analyzed and cross-characterized by spectroscopy, diffraction, adsorption, and elemental analysis methods. Based on the obtained results, we propose a mechanism of transformation from horns to a structure with several layers of sensu-form stacked graphene oxide. As this transformation process proceeds gradually, one can obtain numerous transition nanoarchitectures of tunable morphology and surface physicochemistry, including materials with an extremely high surface area. As OSSGO bears a fraction of the electron-withdrawing and O–H acidic functionalities, electrochemical studies, especially galvanostatic charge–discharge curves and specific capacitance values (significantly higher than those for other carbon-based materials), show potential applications in next-generation supercapacitors. As a result of the large surface areas, we also predict future applications in programmable adsorbents and catalysts with broad-range activity, while the list of applications is incomplete.