Synthesis and characterization of electrochemically prepared ruthenium oxide on carbon nanotube film substrate for supercapacitor applications

Ruthenium oxide was electrodeposited onto a carbon nanotube (CNT) film substrate with a three-dimensional porous structure at the nanometer scale. For comparison, ruthenium oxide was prepared on a Pt plate and carbon paper substrate. Microstructures of the ruthenium oxide-based electrodes examined by scanning and transmission electron microscopy showed that the ruthenium oxide layers (∼3 nm thickness) were electrochemically deposited on the surface of the multiwalled CNT. The ruthenium oxide on CNT film substrate showed not only a much higher specific capacitance of 1170 F/g, but also an improved rate capability, compared with the ruthenium oxide layers on a Pt plate and carbon paper substrate. The improved specific capacitance and rate capability of ruthenium oxide on CNT film substrate are attributed to its electrode construction comprising a very thin film of the electroactive material on a conductive CNT film substrate with a three-dimensional nanoporous structure.