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 degrees 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.

Flexible all-solid-state micro-supercapacitor based on Ni fiber electrode coated with MnO2 and reduced graphene oxide via electrochemical deposition

“…Carbon materials, such as activated carbon [6], carbon nanotubes (CNTs) [7] and graphene [8,9], are normally used as electrode materials in EDLCs while conducting polymers and metal oxides/hydroxides in pseudo-capacitors. Among metal oxides/hydroxides (e.g., RuO 2 , MnO 2 , Co 3 O 4 , Ni(OH) 2 ) [10][11][12][13][14], MnO 2 is one of the most attractive materials because of its high theoretical pseudo-capacitance, low cost and environmental compatibility [4,[15][16][17].…”

Two-dimensional NiCo2O4nanosheet-coated three-dimensional graphene networks for high-rate, long-cycle-life supercapacitors

“…The pseudocapacitor undergoes reversible redox reaction that occurs in the electrode materials, such as metal oxides (RuO 2 , MnO 2 , Co 3 O 4 , NiCo 2 O 4 , CoMoO 4 , etc.) [7][8][9][10][11][12][13][14][15][16] and metal hydroxides (Co(OH) 2 , Ni(OH) 2 , etc. ); [17][18][19] it stores more charges and provides higher specific capacitance than does the EDLC.…”

Inkjet printing of single-walled carbon nanotube/RuO2 nanowire supercapacitors on cloth fabrics and flexible substrates

“…In order to further improve the device performance, we combined ruthenium oxide (RuO 2 ) nanowires with printed SWNT films; the RuO 2 nanowires were synthesized using a chemical vapor deposition (CVD) method. Owing to its unique properties, such as metallic conductivity, intrinsic reversibility of surface redox reactions, and ultrahigh pseudocapacitance, RuO 2 has become one of the most promising electrode materials for electrochemical capacitors [24][25][26]. As we proposed earlier [27], instead of using SWNT films alone, we integrated RuO 2 nanowires together with SWNT films and fabricated hybrid RuO 2 nanowire/ printed SWNT nanostructured films.…”