The Raman spectra of different electrolytes are shown in Figure . The details of ex situ Raman set up and Raman scattering collection details are given in the experimental section and supporting information. Clear changes with varying concentration can be observed in the OH stretching region of H 2 O (between 3000 and 3700 cm -1 ). This broad stretching peak (mode) can be deconvoluted to three other Gaussian distributions, assigned to tetrahedrally coordinated water (solid or ice like water, ~3200 cm -1 ), trihedrally coordinated water (liquid like water, ~3400 cm -1 ), and free water (~3600 cm -1 ), respectively. The contribution of each one of these kinds of water to the overall spectrum is shown in Figure , where the changes in the water co-ordination with varying KOH concentrations are shown.