Anodic composite deposition of hydrous RuO2–TiO2 nanocomposites for electrochemical capacitors

This work employs a simple one-step method, anodic composite deposition, to fabricate hydrous RuO2–TiO2 (denoted as RuO2·xH2O–TiO2) composite films from an aqueous bath containing RuCl3·xH2O and TiO2 nanoflowers for the electrochemical capacitor (EC) application. The composition of composites can be simply controlled by varying the concentration of TiO2 nanoflowers of the rutile phase in the deposition solution. The highly porous morphologies of various RuO2·xH2O–TiO2 composites are characterized with a field emission scanning electron microscope (FE-SEM). The pseudocapacitive performances (e.g., electrochemical reversibility, specific capacitance, electrochemical impedance spectroscopic responses) of relatively thick RuO2·xH2O–TiO2 composites (0.9 ± 0.1 mg cm−2) are systematically investigated. The high-power capacitive behavior of RuO2·xH2O–TiO2 composites, high utilization of RuO2·xH2O and the simple one-step method for electrode preparation indicate the unique merits of anodic composite deposition.

► Anodic composite deposition successfully fabricates hydrous RuO2–TiO2 composites for ECs.
► Ru-rich composites with CS,T ∼ 500 F g−1 in this work are desirable.
► TiO2 nanoflowers act as a porous skeleton to facilitate penetration of electrolytes.