Electrochemistry deals with the interrelationship between electrical and chemical energy. Various potentials appear in electrochemistry and pertain to one another in practical cells. Understanding the electrode potential is an important step in acquiring basic knowledge of electrochemistry and extending it to specific applications. This comprehensive paper outlines the fundamentals and related subjects of electrode potentials, including electrochemical cells and liquid junction potentials. Aqueous solution systems are ideal for connecting the theoretical background of electrode potentials to practical electrochemical measurements. Accordingly, the basic electrode chemistry in aqueous systems is described in this paper, as well as several advanced concepts introduced in recent studies