Methylene blue modified graphene film as high-performance electrode towards all-in-one flexible supercapacitors with “all-graphene” structure

The emergence of wearable electronics has raised the demand for flexible supercapacitors. However, conventional multilayer flexible supercapacitors have high interfacial resistance and unavoidable displacement among adjacent components during the bending process. Herein, a novel all-in-one flexible supercapacitor (AFSC) with “all-graphene” structure is proposed. Benefit from the additional pseudocapacitance enhancement of methylene blue (MB) molecules, the AFSC assembled with the flexible self-supporting MB modified graphene hydrogel film (MB/rGO) obtained by a simple hydrothermal as electrode and graphene oxide (GO) as separator exhibits a high specific capacitance of 317.27 F g−1 at 0.2 A g−1. Even at a high current density of 20 A g−1, the specific capacity still maintains 213.66 F g−1. Besides, the soft package AFSC device shows excellent flexibility, mechanical properties and electrochemical stability. After continuously bending from 0° to 180° for 1200 times, the AFSC device can display a high capacity retention of 90.8%, showing splendid expectation in the field of flexible wearable applications.