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

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.