Flexible solid-state asymmetric supercapacitor based on reduced graphene oxide (rGO)/ruthenium oxide (RuO2) composite electrode

Energy storage in flexible supercapacitor devices extensively depends on electrode design with good electrochemical as well as mechanical properties. Here, a cost-effective and scalable method is proposed for the synthesis of a reduced graphene oxide/ruthenium oxide (rGO/RuO2) composite thin film for flexible supercapacitor. The successive ionic layer adsorption and reaction (SILAR) method used to synthesize rGO/RuO2 composite electrode allowed the synthesis of amorphous RuO2 with optimized rGO composition. The morphological structure of rGO/RuO2 composite examined using a scanning electron microscope showed compact spherical microparticles coated on rGO sheets. The electrochemical measurements of rGO/RuO2 composite electrode revealed that the composite material achieved a specific capacitance of 1371Fg-1 at a scan rate of 5mVs-1. Due to the combined impact of rGO and RuO2, a flexible solid-state asymmetric supercapacitor (FSS-ASC) of configuration rGO/RuO2/PVA-H2SO4/WO3 exhibited Cs of 114Fg-1 at 5mVs-1 with 88% of capacitance retention after 5,000 galvanostatic charge-discharge (GCD) cycles. The FSS-ASC provided a remarkable specific energy of 23Whkg-1 and a specific power of 613Wkg-1. The electrochemical features of rGO/RuO2 composite show a promising way to fabricate flexible supercapacitors.