Chemical Bath Synthesis of Binder‐Free Nickel Vanadate Cathodes for Hybrid Supercapacitor Systems: Tailoring Morphology and Surface Area via Monitoring Hydrolyzing Agent

Abstract To boost the energy storage performance of supercapacitor devices, it is essential to design electrode material through rational manipulation of electrode material with their structural and morphological properties. Therefore, the present study highlights the binder‐free, and scalable synthesis of the nickel vanadate (NV) thin films using a chemical bath deposition approach with the variation of the hydrolyzing agent (urea). The present investigation inclusively demonstrates that variations in urea concentration in the synthesis of NV electrode material substantially influence both physicochemical and electrochemical performance. The optimal concentration (0.075 m) of urea in the synthesis of the C‐NV3 sample provides the nanoparticles of NV with a maximum specific surface area of ∼42.1 m² g⁻¹, delivering a maximum specific capacitance (C_sp) of 692 F g⁻¹ at 1 A g⁻¹ current density. Furthermore, both hybrid aqueous supercapacitor device and hybrid solid‐state supercapacitor device (HSSD) are fabricated. The HSSD exhibits a C_sp of 84 F g⁻¹ alongside a SE of 29.8 Wh kg⁻¹ at an SP of 1120 W kg⁻¹. Thus, the present work opens a pathway to the binder‐free preparation of NV thin films, which are efficient cathodes in practical applications for hybrid energy storage devices.