An asymmetric supercapacitor constructed using an electrochemical double-layer, active carbon positive electrode and a Bi2O3/porous carbon negative electrode in an alkaline solution is presented here. In this study, nanosized Bi2O3 was formed and highly dispersed into a porous active carbon material using a simple process. The characteristics of the Bi2O3 electrode as well as its electrochemical performance in the hybrid device were investigated. A highly reversible redox transit was observed in the cyclic voltammogram of the Bi2O3 loaded electrode. The transformations of Bi(III) to Bi(0) and Bi(0) to Bi(III) are clearly shown in the charge/discharge curve of Bi2O3, with potential plateaus at -0.6 and -0.5 V. The results of this experiment reveal that, with introduction of the Faradic reaction of Bi/Bi2O3, the overall specific capacity of the hybrid supercapacitor during discharge was significantly increased compared to that of a symmetric set-up. (C) 2014 Elsevier B.V. All rights reserved.