Electrolyte‐Dependent Charge Storage Behavior of <scp> V ₂ O ₅ </scp> Nanoparticles for Aqueous Supercapacitors

Abstract

Understanding the interplay between electrode nanostructure and electrolyte chemistry is crucial for designing high‐performance supercapacitors. Here, we investigate the electrolyte‐dependent charge storage behavior of V 2 O 5 nanoparticles synthesized via a facile sol–gel method. Comprehensive structural and morphological analyses confirm uniform V 2 O 5 nanoparticles with high surface area, promoting efficient ion diffusion and redox activity. Electrochemical performance was systematically evaluated in 1 M acidic (H 2 SO 4 ), alkaline (KOH), and neutral (Na 2 SO 4 ) electrolytes using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). Among all electrolytes, KOH delivers the highest specific capacitance of 430 F g −1 at 1 A g −1 (446 F g −1 at 5 mV s −1 ) and excellent rate capability, attributed to high K + ionic mobility and favorable desolvation. Na 2 SO 4 exhibits higher cycling stability, retaining 90% of initial capacitance over 6000 cycles, while H 2 SO 4 provides moderate capacitance (380 F g −1 at 1 A g −1 ) with intermediate stability. This study establishes a direct correlation between electrolyte environment, structural evolution, and electrochemical performance, providing actionable insights for designing durable and efficient V 2 O 5 ‐based supercapacitors.