Structural and electrochemical investigation of Fe-doped sheet-like ZnCo₂O₄ as battery-type electrode for high-performance hybrid supercapacitors

Multi-transition metal spinel oxides with nanostructures have become interesting options for improving the electrochemical performance of next-generation supercapacitors. By synthesizing pure ZCO, 5% Fe-doped ZCO, and 10% Fe-doped ZCO, the structural and electrochemical effects of iron incorporation into ZnCo2O4 (ZCO) spinel structures were methodically investigated in this study. The sheet-like shape of both undoped and Fe-doped ZCO efficiently reduces ion/electron transport resistance and offers many active sites for ion adsorption, which enhances redox kinetics, according to detailed characterization. Notably, Fe doping improved the spinel lattice's electrochemical performance by causing advantageous structural and electrical changes. All electrodes exhibited battery-type footprints, and the 10% Fe-doped ZCO electrode delivered an impressive specific capacity of 421.3 mAh g−1 at 10 A g−1 and maintained 85% of its initial capacity after 2000 charge–discharge cycles, demonstrating excellent cycling stability. Therefore, this study underscores the potential of Fe-doped ZnCo2O4 as a high-performance battery-type electrode material for advanced hybrid supercapacitor applications.