Design and Tailoring of the Nanotubular Arrayed Architecture of Hydrous RuO2 for Next Generation Supercapacitors

Abstract

By use of the membrane-templated synthesis route, hydrous RuO₂ (RuO₂·xH₂O) nanotubular arrayed electrodes were successfully synthesized by means of the anodic deposition technique. The desired three-dimensional mesoporous architecture of RuO₂·xH₂O nanotubular arrayed electrodes with annealing in air at 200 °C for 2 h simultaneously maintained the facility of electrolyte penetration, the ease of proton exchange/diffusion, and the metallic conductivity of crystalline RuO₂, exhibiting unexpectedly ultrahigh power characteristics with its frequency “knee” reaching ca. 4.0−7.8 kHz, 20−40 times better than that of RuO₂ single crystalline, arrayed nanorods. The specific power and specific energy of annealed RuO₂·xH₂O nanotubes measured at 0.8 V and 4 kHz is equal to 4320 kW kg^-1 and 7.5 W h kg^-1, respectively, demonstrating the characteristics of next generation supercapacitors.