Fabrication of high performance asymmetric supercapacitors with high energy and power density based on binary metal fluoride

Abstract

Commercial tetragonal phase MnF2 is exploited as novel and alternative electrode material in asymmetric supercapacitors. Temperature dependent magnetic (M-T) curve evidences the antiferromagnetic transition (AFM) at Neel temperature (68.4 K). High specific capacitances of 406 F/g at 2 A/g and 80 F/g at 1 A/g are achieved in 3 and 2 electrode system, respectively. The asymmetric supercapacitor device retained 82% of its initial capacitance after 5000 cycles even at high window potential of 1.8 V which reveals excellent electrochemical stability. Ragone plot presents very high energy density (35.99 Wh/kg) with power density (822.75 W/Kg) at cell potential of 1.8 V. Electron transport dynamics in MnF2//AC asymmetric supercapacitor is also investigated by Nyquist plot of electrochemical impedance spectroscopy. These research findings demonstrate that MnF2 can serve as efficient electrode material for the electrochemical energy storage device applications. (C) 2020 Elsevier B.V. All rights reserved.