A pH‐Tailored Anodic Deposition of Hydrous RuO 2 for Supercapacitors

A pH‐tailored anodic deposition strategy is reported in this work, by which the hydrous ruthenium oxide (RuO 2 ) can be directly deposited on titanium (Ti) substrates. The prepared RuO 2 electrode exhibits a well kinetic performance (the remarkably low equivalent series resistance of R es ∼2 mΩ and charge transfer resistance of R ct ∼0.11Ω) and a high specific capacitance of 756 F g ‐1 at 0.6 A g ‐1 . More importantly, a symmetric supercapacitor based on the RuO 2 electrode delivers a high specific energy of 24 Wh kg ‐1 at 150 W kg ‐1 . Even at a large specific power of 26.25 kW kg ‐1 , specific energy is still as high as 8.6 Wh kg ‐1 , meanwhile achieving a long lifespan of 98% retention over 100,000 cycles. All of these distinguishing properties not only enable the prepared RuO 2 to be an excellent electrode material for high‐power output and long life supercapacitors, but also indicates that the pH‐tailored anodic deposition strategy reported in this work is effective to prepare high‐performance RuO 2 electrode.