A Flexible Reduced Graphene Oxide-based Paper for Supercapattery Design: Effect of Polyindole Thin Films and Zinc Oxide Nanoparticles

Abstract

Flexible graphene-based paper electrodes (FGPEs) are a new class of study and the research on this electrode material has been carried out for approximately ten years. FGPEs have many advantages compared to classical solid electrodes such as being flexible, foldable, adaptable to flexible electronics, being cut, easily shaped, and effective and adjustable modification. In this work, the applicability of FGPEs modified with polyindole (PIN) thin films and zinc oxide nanoparticles (ZnO-NPs) to energy-storage systems as a supercapattery design is presented, and especially the limitations of ZnO-NPs for energy-storage applications are revealed to inform researchers working for a similar purpose. Capacitance calculations have been performed using both cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) experiments. It was observed that the rGO/PIN paper demonstrated almost 30 times more energy-storage capacity than that of the rGO/PIN/ZnO paper due to the electrochemical instability of ZnO-NPs on the flexible electrode platform at the applied potential region in 1.0 M HClO4 solution. The rGO/PIN paper with a highly flexible property exhibited an energy density of 74.5 W h cm-2 and a power density of 2258 W cm-2 at a current density of 2.2 mA cm-2, revealing hopeful results for future modular and flexible approaches. Fabrication of flexible graphene-based supercapatteries. Electrochemical dissolution of ZnO film in 1.0 M HClO4 solution decreases capacitive performance of rGO/PIN/ZnO//rGO. image