Herein, we report a preparation method of a novel binary hybrid nanocomposite based on polyaniline (PANI) and α-MnO2 nanotubes (MNTs) by in situpolymerization. The polymerization is carried out in acidic medium using α-MnO2 nanotubes as oxidant. A symmetrical supercapacitor is fabricated and the electrochemical performance of the supercapacitor is investigated by cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) techniques using 1.0 M H2SO4 as electrolyte. The nanocomposite shows maximum specific capacitance of 626 F g−1 and corresponding energy density of 17.8 W h kg−1, as calculated from the charge–discharge curve at a specific current density of 2 A g−1 in the potential range 0–0.7 V.