Vanadium pentoxide (V2O5) has emerged as a promising electrode material for aqueous supercapacitors due to its high theoretical capacitance and environmental stability. However, optimizing performance requires understanding how different electrolyte chemistries influence charge storage mechanisms and cycle longevity.
Researchers synthesized uniform V2O5 nanoparticles using a sol-gel method and systematically evaluated their electrochemical behavior in three electrolyte environments: sulfuric acid (H2SO4), potassium hydroxide (KOH), and sodium sulfate (Na2SO4). Characterization confirmed high surface area nanoparticles with excellent morphological uniformity, enabling efficient ion transport and redox reactions.
Electrochemical testing revealed significant performance variations across electrolytes. Potassium hydroxide delivered the highest specific capacitance at 430 F g−1 under standard discharge conditions, with exceptional rate capability. This superior performance stems from superior potassium ion mobility and efficient desolvation at the electrode surface. Sodium sulfate showed moderate capacitance but demonstrated outstanding cycling stability, retaining 90% of initial performance after 6,000 charge-discharge cycles—critical for long-term grid storage applications. Sulfuric acid provided intermediate results, with 380 F g−1 capacitance and moderate stability.
The study employed rigorous electrochemical techniques including cyclic voltammetry, galvanostatic charge-discharge testing, and impedance spectroscopy to characterize performance across multiple current densities and cycle counts. Results established clear correlations between electrolyte ionic properties, electrode structural evolution, and overall device performance.
These findings carry direct implications for energy storage system design. For applications prioritizing power density and response speed, alkaline electrolytes offer advantages. For stationary grid applications requiring extended calendar life, neutral electrolytes become preferable despite slightly lower capacitance. The research provides engineers with quantitative benchmarks for electrolyte selection when developing supercapacitor modules for renewable integration, load leveling, and electric vehicle fast-charging infrastructure.
