The electrochemical behavior of WO3 deposited directly on different substrates was tested in a volume cell using a three-electrode configuration (Figure and). A platinum electrode (Pt mesh; 3 × 4 cm) was employed as the CE and Ag/AgCl (with a 3 mol L⁻ 1 KCl internal electrolyte) as a reference electrode (RE). The performance of WO3 on different substrates, namely Ti (@Ti) and Ni (@Ni) mesh, was evaluated, along with a WO3 powder sample as a free-standing electrode (@SS) composed of 80:15:5 ratio of active material, conductive additive, and binder, respectively (Figure ). In general, the current response of WO3@Ni was not stable in the selected potential window in contrast to WO3@Ti showing high stability across various potential windows. Additionally, the CV curve of WO3@Ni displayed a higher and broader oxidation peak compared to the reduction peak, which may be attributed to the oxidation of the Ni substrate.