Supercapacitors have emerged as promising next-generation energy storage systems owing to their ability to deliver high specific capacitance, improved energy density without sacrificing power density, rapid charge–discharge capability, excellent cycling stability, and cost-effectiveness. To address the ongoing demand for efficient electrode materials, a novel ZnZr2O4 electrode material was synthesized via a conventional sol–gel method. The prepared ZnZr2O4 was characterized by various techniques such as X-ray diffraction with Rietveld refinement, FTIR, FESEM, EDX, and BET surface area analysis. XRD confirmed the formation of a single orthorhombic spinel phase, while FTIR spectra revealed Zn–O and Zr-O-Zr vibrational modes, indicating successful spinel formation. Morphological studies showed nano to microscale lumpy grains with an average particle size of 27 nm, and EDX mapping confirmed uniform distribution of Zn, Zr, and O elements. Electrochemical investigations revealed predominantly diffusion-controlled charge storage, and ZnZr2O4 exhibited a specific capacitance of 144 F g−1 at 0.7 A g−1 in a three-electrode setup (1 M KOH). Furthermore, an asymmetric supercapacitor device was assembled using ZnZr2O4 (positive electrode), Carbon C72 (negative electrode), and PVA-KOH gel electrolyte. The device operated efficiently within a 2.1 V potential window, delivering a specific capacitance of 57.14 F/g at 0.35 A/g, a maximum energy density of 35 Wh/kg at 525 W/kg, and a peak power density of 1350 W/kg. In addition, long-term cycling stability demonstrated 76% capacitance retention after 5000 cycles with 99% coulombic efficiency, confirming ZnZr2O4 as a promising electrode material for high-performance supercapacitor applications. This study can serve as a useful reference for developing efficient and cost-effective energy storage devices with strong potential for commercial applications.
