Nano-flowered manganese doped ferrite@PANI composite as energy storage electrode material for supercapacitors

Abstract Herein, we report a 3D nanoflower MnFe2O4@PANI composite as electrode material in supercapacitor. Manganese doped ferrites were synthesized by hydrothermal method followed by in-situ chemical oxidative polymerization of aniline to form a nanoflower composite. The nanoscale MnFe2O4 were infused with polyaniline (PANI) that offer superior synergistic effects by favouring access to charge/ion transit route, which is further improved by providing a broad surface area that is electrochemically active. It is entrenched that MnFe2O4@PANI involves charge transfer pseudocapacitance at both the ionic sites of Mn and Fe and oxidized emeraldine salt of PANI, balanced by the inclusion/exclusion of proton within/outside the lattice. On the one hand, the fluffy nature of PANI provided channels for charge transport, and manganese ferrites helped in storing the electrons through changes in the valence state of the active sites. We obtained a high specific capacitance of 623 F/g at a current density of 1 A/g. A prototype of the developed supercapacitor showed excellent device performance with a high energy density of 179 Wh/kg and maximum power density of 982 W/kg with ~95% retention of specific capacitance after 10,000 cycles.