Polarization and adsorption effects on the wettability of a gold electrode by lithium, sodium, potassium, and cesium chloride melts

Abstract

To establish the patterns of the wettability of solid surfaces by ionic melts, the wetting energy of a gold electrode by lithium, sodium, potassium, and cesium chloride melts was studied as a function of the electrical potential applied to the electrode. It was established that when the potential was shifted in the positive direction relative to the zero-charge potential of gold in the corresponding melt, the shape of the curve that defined the dependence of the wetting energy on the electrical potential varied according to the salt composition: for lithium and sodium chlorides, the wetting energy increased monotonically, while in potassium and cesium chloride melts there was a maxima. This phenomenon was explained from the standpoint of the mutual polarization of gold and chlorine ions in the place of their direct contact. At a certain electric field strength in the double electric layer and at a certain binding energy of the melt particles, the resultant mutual ion polarization led to the formation of ordered layers of ionic associations (presumably AuCln(n − 1)-) on the anode surface, which shielded the electrode charge.