Enhanced activity of microwave synthesized hierarchical MnO2 for high performance supercapacitor applications

► α-MnO2 samples were synthesized using microwave-assisted and reflux methods. ► Microwave synthesized α-MnO2 shows higher rate pseudocapacit-ance. ► Microwave synthesized α-MnO2 shows lower ESR, IR drop and capacitance retention. ► Microwave synthesized α-MnO2 shows high power and energy density.