Electrochemistry is a branch of physical chemistry that deals with the relationship between an electrical potential difference, as a measurable and quantitative phenomenon, and an identifiable chemical change, with the potential difference being the result of a specific chemical change, or vice versa. These reactions involve electrons moving through an electronically conductive phase (usually an external electrical circuit, but not necessarily, as in an electroless coating) between electrodes separated by an ionically conductive and electronically insulating electrolyte (or ionic species in solution).
