Dispersing WO3 in carbon aerogel makes an outstanding supercapacitor electrode material

Tungsten oxide, originally poor in capacitive performance, was made an excellent electrode material for supercapacitors, by dispersing it to carbon aerogels (CA), a conductive and mesoporous hosting template, that drastically improved the utilization of WO3 for capacitance generation. The WO3 was introduced to the CA, in a form of well-dispersed single crystalline nanoparticles of 15–40 nm in size, with a simple immersion-calcination process. A one order of magnitude improvement in specific capacitance was achieved with the present composition, from 54 F/g for WO3 nanoparticles to 700 F/g for WO3/CA composites (scaned at 25 mV/s in 0.5 M H2SO4 over a potential window of −0.3 to 0.5 V). The WO3/CA composites exhibited an excellent high rate capability with a 60% retention in specific capacitance at 500 mV/s, almost perfect cycle efficiency of 99%, and outstanding cycling stability of only 5% decay in specific capacitance after 4000 cycles.