Co2MnO4/Co hydroxide chloride (CMO/CHC) nanocomposite is firstly obtained through an electrochemically alternating voltage methodology for supercapacitor applications. The CMO/CHC electrode materials display a high specific capacitance of 779Fg−1 at 1Ag−1 and an excellent rate behavior (77.5% and 63.6% at 20 and 40Ag−1 compared with 1Ag−1, respectively). An asymmetric supercapacitor based on CMO/CHC as cathode and activated carbon (AC) as anode presents a maximum energy density of 27.8Whkg−1 at power density of 570.9Wkg−1.