High energy density performance of hydrothermally produced hydrous ruthenium oxide/multiwalled carbon nanotubes composite: Design of an asymmetric supercapacitor with excellent cycle life

Hydrous ruthenium oxide (h-RuO2) nanoparticles and its composite with multiwalled carbon nanotubes (h-RuO2/MWCNT) were synthesized by a simple hydrothermal method and proved to have potential application as hybrid supercapacitor material. The h-RuO2 and h-RuO2/MWCNT were characterized for their physico-chemical properties by PXRD, BET surface area, Raman, SEM-EDS and TEM techniques. The electrochemical performance of the materials were investigated, specific capacitance (Cs) of h-RuO2 and hRuO(2)/MWCNT estimated by their cyclic voltammetric studies were found to be 604 and 1585 F/g respectively at a scan rate of 2 mV/s in the potential range 0-1.2 V. Further, this value was found to be nearly three times higher than that of pure h-RuO2. An asymmetric supercapacitor (AS) device was fabricated by employing h-RuO2/MWCNT as the positive electrode and activated carbon as the negative electrode. The device exhibited Cs of 61.8 F/g at a scan rate of 2 mV/s. Further, the device showed excellent long term stability for 20,000 cycles with 88% capacitance retention at a high current density of 25 A/g. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.