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 voltammograms, 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 5000cycles, and the capacity loss in constant current–constant voltage mode is no more than 4.75% after 2500cycles.