A hybrid battery-supercapacitor (LiMn2O4 + AC)/Li4Ti5O12 using a Li4Ti5O12 anode and a LiMn2O4/activated carbon (AC) composite cathode was built. The electrochemical performances of the hybrid battery-supercapacitor (LiMn2O4+AC)/Li4Ti5O12 were characterized by cyclic voltamniograms. electrochemical impedance spectra, rate charge-discharge and cycle performance testing. It is demonstrated that the hybrid battery-supercapacitor has advantages of both the high rate capability from hybrid capacitor AC/Li4Ti5O12 and the high capacity from secondary battery LiMn2O4/Li4Ti5O12. Moreover, the electrochemical measurements also show that the hybrid battery-supercapacitor has good cycle life performance. At 4C rate, the capacity loss in constant current mode is no more than 7.95% after 5000 cycles, and the capacity loss in constant current-constant voltage mode is no more than 4.75% after 2500 cycles. (C) 2008 Elsevier B.V. All rights reserved.