As mentioned earlier, the present study aims to analyze the solid-electrolyte interactions at the early stages of SEI formation. Our analysis focuses on the NaOTF WiS solution, a promising electrolyte for Na-ion battery applications, and models the adsorption of various electrolyte components on either graphite or sodium metal electrodes. To this end, we examine the possible ion-ion and ion-water structures present at the high salt concentrations associated with a WiS regime. As detailed in our previous study , at these concentrations, the NaOTF WiS electrolyte consists of two distinct domains: an ion-rich domain, primarily composed of aggregated ions, and a water-rich domain containing either partly or fully solvated ion pairs. To explore the adsorption behavior of potential aggregated ion structures, we separately model adsorption complexes containing a single NaOTF ion pair, a single Na2OTF structure, and a single NaOTF2 structure, each in the absence of water. Although this approach neglects some details of mutual interactions in real-world large aggregates, configurations examined effectively represent the major sub-structures within the ion-rich domain. For the water-rich domain, we model both a contact ion pair, where the partly solvated cation and anion are in direct contact, and a solvent-separated ion pair, where both ions are fully solvated but share a portion of their solvation shells. These two structures are modeled as single ion pairs surrounded by an adequate number of water molecules, as discussed in section 4.3.