Hybrid nanowires and nanoparticles of WO3 in a carbon aerogel for supercapacitor applications.

In the field of electrochemical energy storage, incorporation of metal oxides into porous carbon has attracted significant attention. Since each advantage of nanoparticles and nanowires of metal oxide has been distinguished for supercapacitor applications, a combination of the advantages of both structures together can meet a capacitive synergy. In this study, WO3 nanowires and nanoparticles were first incorporated into a carbon aerogel (CA) simultaneously via a facile and one-pot route. A comparative study on the capacitive properties of this novel hybrid structure and single nanoparticles in CA was conducted. The introduction of WO3 nanowires with diameter <40 nm provided an additional pair of redox peaks and improved the specific capacitance by 50% and the rate capacity by 61%. The composite within the hybrid nanowires and nanoparticles exhibits an excellent cycling stability of only 2% decay in specific capacitance detected at 50 mV s-1 for 1000 cycles. The individual contribution of nanowires and nanoparticles to the enhanced capacitance has been discussed, and the enhanced capacitive properties can be ascribed to the hybrid structure better for charge transport during the electrochemical process. More importantly, this route can be extended to incorporate nanowires of other metal oxides into mesoporous carbon, and enhanced capacitive properties can be expected.