Generally, the electrolytes with smaller cation size such as H2SO4 show a higher current response (Figure ) than those with bigger cation size as MgSO4 (Figure ). The ion size and charge of cations such as H + , Li + , Na + , K + , and Mg 2+ plays a crucial role in the intercalation behavior of h-WO3. Smaller ions like H3O + (100 pm) and Li + (76 pm) can diffuse quickly and easily within the h-WO3 lattice, allowing efficient and reversible insertion and extraction. This property enhances the performance of systems like lithium-ion batteries, as it minimizes structural strain and supports high cycling stability. In contrast, larger cations such as Na + (102 pm) and K + (138 pm) introduce more significant lattice distortion during intercalation, which can slow down diffusion and compromise long-term structural integrity.