Potassium perruthenate-treated carbon nanotube sheets for flexible supercapacitors

High-throughput production of flexible, all-solid-state supercapacitors can be accomplished by integrating redox-functionalized commercial carbon nanotube sheets with H2SO4/PVA/H2O polymer hydrogel electrolyte. The chemical composition, elemental oxidation states, and crystallinity of the pristine and 0.02 M potassium perruthenate-treated multi-walled carbon nanotube (MWCNT) sheets are examined using X-ray photoelectron spectroscopy and X-ray diffraction. In assembled hydrogel-based supercapacitor cells, ruthenium oxide-decorated MWCNT sheet electrodes exhibit a specific capacitance of 96 F/g at 1.0 A/g and good cycle stability.

► Flexible supercapacitors prepared using MWCNT sheet electrodes and hydrogel electrolyte. ► Solution treatment of MWCNT sheets with KRuO4 leads to RuO2·xH2O functionalization. ► 200 °C annealing induces change from amorphous RuO2·xH2O to polycrystalline RuO2. ► Demonstration of H2SO4/PVA/H2O hydrogel electrolyte with RuO2-MWCNT electrodes. ► RuO2-MWCNT has Csp of 96 F/g at 1.0 A/g with good rate capability and cycle stability.