We introduced the above analytical model in the context of zeosils, but it can be applied to various hydrophobic porous materials such as MOFs, provided that the same hypotheses are satisfied (i.e. no alteration of the porous material and only water molecules intruded inside it). We compare experimental data for intrusion pressure of various zeosils 58 with prediction obtained from our analytical model and with the van 't Hoff law of osmotic pressure expressed In Figure , we provide in addition the histogram of intrusion pressures predicted by the van 't Hoff law of osmotic pressure that both underestimates for most electrolytes the intrusion pressure and does not distinguish between electrolytes that produce the same ideal entropy of mixing, because at the studied concentration, electrolytes are ideal as previously shown in Figure . The small variation of intrusion pressure existing within the series of electrolytes that can be rationalized in term of activity of water depends on the concentration and of the nature of the electrolyte, providing that input activity coefficients are properly parameterized. It is crucial from a practical point of view because at a given concentration, the electrolyte solution characterized by the lowest water activity such as LiCl results in the highest intrusion pressure and thus stored energy inside the material. This latter point is not taken into account by the van 't Hoff law for which electrolytes behave as ideal solutions.