Phase specific α-MnO 2 is synthesized by reduction of KMnO 4 in microbial fuel cell. Electrochemical characterization of synthesized α-MnO 2 in aqueous 1M Li 2 SO 4 electrolyte exhibit supercapacitor behaviour with initial specific capacitance of 558 mF/g and is 3.77 times higher than its theoretical capacitance. After 50 cycles, α-MnO 2 maintained specific capacitance of 250 mF/g which is 1.69 times higher than the theoretical capacitance of 148 mF/g. Decay in the specific capacitance is noticed after 2000 cycles upto 50 mF/g. © 2018 Hydrogen Energy Publications LLC