1. Introduction and Basic Concepts

Chapter 1 deals with the definitions of some general and specific terms concerning the electrochemistry of solid–liquid interfaces. The definitions of the terms “electrode” and “solid electrode” as well as selected concepts in electrochemistry and surface science are discussed. It has been stressed that a “solid electrode” is a multicomponent, multiphase electrochemical system, containing at least one solid phase, which means that it cannot be treated as a pure solid in vacuum. It has been concluded that in case of a “solid electrode,” the experimentally determinable quantity is the change of the intensive parameter conjugate to the interface area. This quantity is intimately related to the properties of the solid-liquid interface and not just to the properties of the surface of the solid phase; therefore, it seems reasonable to refer to it as the “interface stress change” or “interfacial stress change.”