Redox electrolyte mediated performance enhancement in aqueous zinc ion hybrid supercapacitors composed of spinel BaFe2O4 and cubic Cu2O

Abstract

The conception and advancement of materials for highly efficient electrochemical energy storage devices is of critical importance. This paper propounds the convenient synthesis and rational unification of spinel BaFe₂O₄ and polymer-mediated self-assembled cubic Cu₂O for high-performance zinc-ion hybrid supercapacitors (ZHSCs). The electrochemical characteristics of ZHSC were investigated using two different electrolytes: conventional (C-ZHSC) and redox additive doped (potassium ferro cyanide K₄[Fe (CN)₆]) (Re-ZHSC). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy analyses of wet-chemically generated materials validate concurrency with the literature. The specific surface area (SSA) of the BaFe₂O₄@Cu₂O;18.29 m² g⁻¹ composite was increased roughly nine times above the SSA of Cu₂O, 2.03 m² g⁻¹, whereas the SSA of BaFe₂O₄ was the greatest at 29.39 m² g⁻¹. The electrochemical analysis revealed that the BaFe₂O₄@Cu₂O hybrid had a maximal specific capacitance (Sc) of 803 F g⁻¹ at a current density of 1 A g⁻¹. Furthermore, the composite demonstrated an expanded potential window of −1.2 to 0.42, contributing to its enhanced performance. However, the recorded maximum Scs and potential window of pristine materials Cu₂O and BaFe₂O₄ were just 462 F g⁻¹ and 0–0.42 volts and 593 F g⁻¹ and −1.2–0.42 volts, respectively, at the same current density. The assembled C-ZHSC achieved the highest Sc of 165 F g⁻¹ at a current density of 1 A g⁻¹ with a potential window of 0.8–2.2 volts. The recorded maximal energy (ED) and power densities were 45 W h kg⁻¹ and 27 W kg⁻¹, respectively. Furthermore, the generated Re-ZHSC outperformed C-ZHSC in terms of Sc, ED, and PD by ∼2.5 (404 F g⁻¹ with a potential window of 0.6–2.2 volts), ∼3.2 (144 W h kg⁻¹), and ∼1.4 (37.000 W kg⁻¹) times, respectively. Furthermore, the cyclic stability of Re-ZHSC has shown a sixfold improvement (84%) compared to C-ZHSC (78%), with approximately 7% less dendrite formation. These results authenticate BaFe₂O₄@Cu₂O as a considerably appealing compound for ZHSCs.