Tailored synthesis of RuO₂-V₂O₅ nanocomposites by controlled spray pyrolysis: Unlocking high-efficiency energy storage electrodes

The tailored synthesis of vanadium pentoxide (V₂O₅)-based electrodes holds immense promise for advancing high-performance electrochemical energy storages. However, the practical use of V₂O₅ is hindered by its inherently low electrical conductivity and structural degradation during prolonged cycling. To address these essential challenges, ruthenium dioxide (RuO₂) is strategically integrated as a secondary oxide to form hybrid RuO₂-V₂O₅ nanocomposites through a controlled spray pyrolysis. In this process, ruthenium precursors with various concentrations (0.5–10 wt%) are incorporated into a vanadium precursor solution, followed by the deposition onto the preheated stainless-steel substrates, to tailor the morphology of the resulting thin-film nanocomposite (thickness <10 μm). The optimized RuO₂-V₂O₅ nanostructures exhibit excellent hydrophilicity and feature a unique architecture of two-dimensional RuO₂ nanosheets uniformly dispersed over the V₂O₅ matrix. This configuration establishes RuO₂-V₂O₅-interconnected conducting pathways that significantly enhance charge transport and efficient ion diffusion. Remarkably, the 6 wt% RuO₂-V₂O₅ electrode achieves a high specific capacitance of 1223.48 F g⁻¹ (734.09 C g⁻¹) in a 6 M KOH at 0.1 A g⁻¹. Furthermore, an asymmetric device fabricated with the optimized RuO₂-V₂O₅ electrode delivers an impressive energy density of 14.40 Wh kg⁻¹ and a power density of 35.71 kW kg⁻¹, while maintaining ∼98 % efficiency and 85.34 % capacitance retaining over 10,000 cycles. These findings highlight a promising route for fabricating stable and scalable nanocomposite electrodes for practical energy storage systems.