Paper-based supercapacitor from electrochemical synthesis of polyaniline doped with reduced graphene oxide

Abstract

Freestanding and scalable paper-based supercapacitors were prepared by a one-step electrochemical method. As the electrode materials, polyaniline (PANI)-reduced graphene oxide (rGO) composites were synthesized by in situ electro-polymerization and electrochemical reduction of graphene oxide. The cellulosic paper, which is essential for this method, was coated with the PANI-rGO composites by a two-electrode cell in the sulfuric acid solution. The morphology and chemical structure of the PANI-rGO paper were confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical storage properties were evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge measurements. For the PANI-rGO paper, a high specific capacitance of 98 F∙g-1 was obtained at a scan rate of 20 mV∙s-1 compared to 83 F∙g-1 for pure PANI, and it maintains its capacitance up to 86% over 1000 cycles. In addition, from the impedance study, the pseudocapacitive behavior of the PANI-rGO was evaluated by measuring each parameters in the equivalent circuit. The PANI-rGO paper can be applied to the flexible supercapacitor due to its flexibility, and it is demonstrated by getting the similar cyclic voltammogram even though the PANI-rGO paper-based supercapacitor is bent.