Electrochemical cells, terminology

Electrochemical cells produce electrical energy from a spontaneous chemical reaction. In electrolysis, the process is reversed so that electrical energy is used to carry out a nonspontaneous chemical change. A cell arranged to do this is called an electrolytic cell. An electrolytic cell is similar to an electrochemical cell except that an electrolytic cell s circuit includes a power source, for example, a battery. The same electrochemical cell terminology applies to electrolytic cells. Reduction occurs at the cathode and oxidation at the anode. 

We now look at some examples of redox reactions involving simple cations in aqueous solution. Electrochemical terminology will often be encountered, since e.m.f. measurements on electrochemical cells are important sources of thermodynamic data in this area. For example, the reduction potential ° for the half-reaction ... 

Impedances of Electrochemical Systems Terminology, Nomenclature and Representation. Part I. Cells with Metal Electrodes and Liquid Solutions, (prepared for publicaUon by M. Sluyters-Rehbach) PureAppL Chem. 66 (1994) 1831. 

Table 2.2 Summary of electrochemical cell conventions, terminology, and relationships...

Chlorine gas is liberated at the positive electrode and caustic soda and hydrogen are formed at the negative electrode. The hydrogen, although pure, is usually seen as a by-product of low value that may be pumped to a nearby oil refinery or burnt to raise steam. (The terminology used for electrochemical cells is outlined in Box 4.1.)... 

The terminology adopted to describe electrochemical cells implies that a spontaneous process has a positive electrode potential. cell defines the maximum work (free energy), AG, that a cell can provide ... 

The number of possible galvanic cells that could be built is almost unhmited. All of them have common features, and terminology has been devised to describe these features. The electrically conducting sites at which either oxidation or reduction take place are called electrodes. Oxidation occurs at the anode and reduction occurs at the cathode. These terms are also used for other types of electrochemical cells, too, not just for galvanic cells. 

Sluyters-Rehbach M. Impedances of electrochemical systems terminology, nomenclature and representation, part I cells with metal electrodes and liquid solutions. Pure Appl Chem 1994 66 1831-91. 

This chapter has presented a brief history of fuel cell evolution, the electrochemical fundamentals of PEM fuel cells, PEM fuel cell concepts and terminology, as well as performance analysis. Its main purpose has been to provide readers with some introductory and background information for a fundamental understanding of fuel cell AC impedance, to facilitate their journey through the next several chapters. 

In electrochemical terminology, the vessel in which electrochemical transformation occurs is called the cell. To bring the terminology in line with that of chemical reaction engineering, we refer to it as the electrochemical reactor (ECR). An ECR is one in which electrical energy is converted into chemical... 

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