Hierarchically Structured 3D Nanoporous Vanadium Oxide Transparent Electrodes for Next-Generation Supercapacitors

This article describes the automatic spray pyrolysis deposition (ASPD) process for the synthesis of hierarchically structured 3D nanoporous vanadium oxide (V₂O₅) transparent material on a fluorine-doped tin oxide (FTO) substrate. The deposition of material occurs at 673 K using an aqueous solution of NH₄VO₃, with a constant solution spray rate of 10 mL min⁻¹ and airflow rate of 10 L min⁻¹. Structural analysis confirms the pure orthorhombic structure formation of the V₂O₅ material, while FE-SEM images show a well-organized 3D spongy-like porous architecture. The excellent conformality of the ASPD enables the deposition of high-aspect-ratio 3D structured nanoporous V₂O₅ electrodes for next-generation supercapacitor applications. The hierarchical structured 3D nanoporous V₂O₅ electrode exhibits superior electrochemical performance in a 1M Na₂SO₃ electrolyte. Within the potential window 0 to -1.3 V, the electrode archives the highest specific capacitance (SC) of 453.32 F g⁻¹ and also retains 86% of its capacitance after 5000 cycles. These properties mainly originate from the crystallinity, 3D nanoporous structure, and fast and easy ionic intercalation through the material. Furthermore, a symmetric supercapacitor device using this electrode is fabricated and which yields outstanding electrochemical performance. Overall, the results highlight the potential of 3D nanoporous V₂O₅ as an outstanding electrode material for next-generation supercapacitor applications.