On the evolution and application of the concept of electrochemical polarization
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On the evolution and application of the concept of electrochemical polarization Dóra Zalka 1,2
&
László Péter 1
Received: 29 April 2020 / Revised: 27 May 2020 / Accepted: 28 May 2020 # The Author(s) 2020
Abstract This paper yields an overview on the evolution of the concept of polarization applied to electrochemical systems, ranging from electrodes to cells. The historical discussion starts at the early phase of the development of electrochemistry when currentcontrolled measurements were possible only, and when the early definitions of polarization, depolarization and depolarizer were created. A number of contemporary handbooks, recommendations and other reference resources are listed in which these concepts are represented in various ways, from conservative definitions to attempts of redefining them. The traditional definitions are confronted with the everyday use of professional language, drawing attention to the fact that the widespread application of potential-controlled electrochemical measurements led to new meanings. Some suggestions are made that open room for the application of the term of polarization in accord with the modern methodologies, without compromising the traditional introduction of the term. Polarization-related phenomena in biological membranes are not dealt with in the present work. Keywords Electrode polarization . Depolarization . Depolarizer . Current control . Potential control
The beginning: early measurements and definitions During the early development of electrochemistry, the general method of the control of an electrochemical cell was based on the current passed through this cell. While the current was taken as the independent (technically variable)1 parameter, 1 Throughout the paper, the expression “independent variable” shall refer to the one that is controlled (regulated) during the experiment. The discussion will be constrained to electrodes (or cells) for which the potential and the current density are in a mutually unambiguous relationship; therefore, the controlled and measured parameter can be technically exchanged without modifying the j–E relationship. Concerning causality, the parameter whose variation results in a change of the other can be arbitrarily selected. It will be shown that the authors believe that, as an analogy to the transport process, the difference in the intensive parameters should be regarded as the driving force which causes the transport of the corresponding extensive quantity, which means the potential difference is the cause of the current. However, the reverse choice is equally possible and can lead to the same the j–E relationship, even though the j–E function is never evaluated along this line.
* László Péter [email protected] 1
Wigner Research Centre for Physics, Konkoly-Thege út 29-33, Budapest 1121, Hungary
2
Hevesy György PhD School of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, Budapest 1117, Hungary
the deviation of the cell voltage from its initial value was taken as the consequence (in other
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