Facile synthesis and electrochemical performance of FeVO4 nanoparticles as negative electrodes in supercapacitors

The growing global demand for reliable and sustainable energy has intensified efforts to develop advanced energy storage technologies. Supercapacitors have emerged as a critical solution due to their high power density, fast charge–discharge rates, and excellent cycle life, making them essential for portable electronics, electric vehicles, and hybrid energy systems. In this study, FeVO₄ nanospheres were synthesized via a facile sol–gel combustion method and evaluated as a high-performance negative electrode material for supercapacitor applications. Structural and morphological analyses (XRD, SEM, XPS) confirmed the formation of pure-phase triclinic FeVO₄ with well-defined nanostructures and appropriate valence states of Fe and V. Electrochemical investigations, including cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS), revealed dominant pseudocapacitive behavior governed by diffusion-controlled redox reactions. The FeVO₄ electrode exhibited a remarkable specific capacitance of 928 F g^–1 at 1 A g^–1 and retained 98.06% of its initial capacitance after 10,000 cycles, indicating superior cycling durability. Notably, this study demonstrates the potential of FeVO₄ nanospheres as a cost-effective, robust, and scalable negative electrode material for asymmetric supercapacitor device fabrication-underscoring its novelty among vanadate-based pseudocapacitors.