Given the relatively large experimental Li + solvation free energy of -4.985 eV , it is crucial to include solvation effects for the adsorbed cations. As shown in Fig. (c) for the system at 5/6 ML water coverage, the strong interaction between water molecules and Li + , as well the hydrogen bond formation between water and the surface, lead to further stabilization of the interface structure and appearance of Li + adsorption in the high potential and pH region of the Pourbaix diagram. Thus, there is a competitive adsorption between Li + and protons, similar to the competitive adsorption between chloride and protons on Pt(111) .