Similarly, we investigated the dependence of ionic conductivity modulation on anion species. We selected lithium cation as the cation species because we observed very weak modulation in the ionic conductivity even under vibrational ultra-strong coupling. Figure illustrates the dependence of ionic conductivity in 0.01 M LiX aqueous electrolyte solutions (X = F, Cl, and Br). Fluoride and chloride anions exhibited similar values even under the vibrational ultra-strong coupling regime. On the other hand, the ionic conductivity of LiBr aqueous electrolyte solution in the cavity showed three times higher value than the bulk ionic conductivity of LiBr aqueous electrolyte solution. We also attempted to evaluate the ionic conductivity using LiI; however, due to the corrosion abilities of iodide on the Au surface, the mirrors were peeled off. The noise in the scattering of ionic conductivities may arise from the instability of the cell in the electrolyte solution. Through systematic investigation, we have demonstrated the independent modulation of cationic or anionic conductivity through vibrational coupling of ionic hydration.