Exploring the effect of oxygen plasma on SnS₂-ZnFe₂O₄based supercapacitor electrodes

The present study focuses on the fabricate the SnS₂-ZnFe₂O₄compound to be employed as electrode materials in pseudocapacitors and raise its capacitance via direct-current O₂plasma (DCOP) treatment. To maximally increase the capacitance of the constructed electrodes, the best conditions concerning temperature, exposure time, and power, as features of DCOP, were initially determined. Using the three-electrode cyclic voltammetry measurements, the electrodes exhibited the highest specific capacitance (733 F g^-1) when the exposure time, output power, and temperature were set to 25 min, 1700 W, and 25 °C, respectively. The energy and power densities of the fabricated symmetric supercapacitor were estimated to be 43.5 Wh kg^-1, which is considered substantially high, and 750 W kg^-1, respectively, at a highest operating voltage of 1.5 V. The functional groups of the created electrodes were also analyzed, and it was found that the reason for considerable increases in the capacitance was improvement of the functional groups comprising oxygen such as O-Sn-O, Sn-O-C, and Fe-O on the surface of the SnS₂-ZnFe₂O₄electrodes.