Fabrication and electrochemical study of ruthenium-ruthenium oxide/ activated carbon nanocomposites for enhanced energy storage

In this study, nanocomposites consisting of crystalline Ru and RuO2 nanoparticles have been successfully synthesized via a hydrothermal method in the presence of urea followed by calcination. The effect of calcination temperatures on the formation of the Ru and RuO2 nanocomposites are systemically investigated. Our experimental results have shown that the applied annealing temperature of 300 degrees C facilitated the formation of the nanostructured Ru and RuO2 composite with a large surface area. Further, novel Ru-RuO2 nanoparticle/activated carbon (Ru-RuO2/AC) composites are prepared and tested as an advanced supercapacitor material for energy storage. Our experimental results reveal that the optimized composition of the Ru-RuO2/AC nanocomposite consists of 10 wt.% of Ru-RuO2 and 90 wt.% of AC, and that the specific capacitance of the developed nanocomposite is 1460 Fg(-1) (in terms of Ru-RuO2) at a current density of a 10Ag(-1) in a 0.5 M H2SO4 electrolyte, which is much higher than many other RuO2 based binary composites reported in the literature. In addition, this new Ru-RuO2/AC nanocomposite exhibits a high charging/discharging rate capability and excellent stability. An approximately 94% retention of the initial specific capacitance is achieved over 10,000 cycles at a charging/discharging current density of 50 Ag-1. (C) 2018 Elsevier B.V. All rights reserved.