High performance α-Fe2O3/rGO based prototype asymmetric coin cell supercapacitor in hybrid electrolyte

Abstract

Electrodes material and electrolytes play an important role in defining energy storage performance of supercapacitors. Therefore, the selection of suitable electrode material as well as electrolyte is very crucial. In this work, hematite α-Fe₂O₃ nanoparticles supported rGO structure is synthesized by a low cost co-precipitation approach. The developed electrode is investigated for supercapacitor in 1.0 M KOH, Na₂SO₄ and aqueous hybrid electrolyte. It is found that the fabricated (α-Fe₂O₃/rGO) electrode delivers an improved specific capacitance of 1272 F g⁻¹ at 1 A g⁻¹ in hybrid electrolyte as compare to 700 F g⁻¹ for KOH and 978 F g⁻¹ for Na₂SO₄ electrolyte. Moreover, the electrode shows excellent cyclic stability in contrast to the pristine α-Fe2O3 electrode. Interestingly, the assembled prototype asymmetric coin cell supercapacitor (α-Fe₂O₃/rGO//AC) device achieved a specific capacitance of 152 F g⁻¹ at 1 A g⁻¹ and energy density of 47.1 Wh kg⁻¹ at a power density of 245.5 W kg⁻¹. Moreover, the device keeps 94% capacitance retention up to 8,000 cycles at 6 A g⁻¹. The improved performance is attributing to the increase in conductivity and charge kinetics in hybrid electrolyte. It is suggested that α-Fe₂O₃/rGO structure is a useful material for supercapacitors in the presence of hybrid electrolyte.