A hybrid supercapacitor, which was assembled with an H-insertion negative carbon electrode and an electrochemical double-layer positive electrode, was studied and its structure was optimized. The electrochemical performance of the individual electrode with different negative to positive electrode mass ratios was investigated. It has been demonstrated that the performance of the hybrid supercapacitor is closely related to the electrode balance. The results indicated that for carbon electrodes used in the study, the capacity of the H-insertion electrode could be fully utilized when the mass ratio of the negative to positive electrode is about 1:6. (C) 2012 Elsevier B.V. All rights reserved.