Low temperature anomalies in the properties of the electrochemical interface

Some features of the adsorption isotherms and electrochemical capacitance o f electrolytes in solvents at low temperatures are studied by means of comp uter simulations. The so-called restricted primitive model where the ions a re represented as charged hard spheres of equal diameter and the solvent is represented by a uniform dielectric constant is used. It is found that at low temperatures the capacitance of double layers in dissolved electrolytes decreases with decreasing temperatures. This is similar to the behaviour o f the capacitance of molten salt double layers but opposite to the behaviou r of double layers in dissolved electrolytes at room temperature. Further, we find a maximum in the adsorption isotherm near the critical point of the electrolyte. This quantity may well be singular at the critical point, (C) 1999 Elsevier Science B.V. All nights reserved.