Abstract
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 WO 3 for capacitance generation. The WO 3 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 WO 3 nanoparticles to 700 F/g for WO 3 /CA composites (scaned at 25 mV/s in 0.5 M H 2 SO 4 over a potential window of -0.3 to 0.5 V). The WO 3 /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. © 2013 Elsevier Ltd. All rights reserved.