Highly Dispersed RuO2 Nanoparticles on Carbon Nanotubes: Facile Synthesis and Enhanced Supercapacitance Performance

RuO2/CNT nanocomposites with well-dispersed RuO2 nanoparticles (diameter <2 nm) on the carbon nanotubes' surface, synthesized through an easy and efficient solution-based method, have been investigated for potential application in electrochemical capacitors (ECs) as electrode materials. The electrochemical results demonstrate that the supporting material of CNT can significantly promote the supercapacitance performance of RuO2. The RuO2 nanoparticles in the composite with a RuO2/CNT mass ratio of 6:7 could achieve a specific capacitance of as high as 953 F g−1. The results also demonstrate that the resulted RuO2/CNT nanocomposites are superior electrode materials for ECs with a high specific capacitance and significantly enhanced high-power and high-energy capabilities as well as improved cycling performance compared with bare RuO2. At a power density of 5000 W kg−1, the RuO2/CNT composite (RuO2/CNT = 6:7 in wt %) can still deliver an energy density of 16.8 Wh kg−1, which is about 5.8 times larger than that of bare RuO2 (2.9 Wh kg−1). The much improved electrochemical performances could be attributed to the dispersive action and good electronic conductivity of CNTs as well as the pinning effect for nanosized RuO2 particles on the CNTs' surfaces.