2-Allen J. Bard Et Al., ELECTROCHEMICAL METHODS Fundamentals And

References

1-Jin Koryta et al., Principles of Electrochemistry, Second Edition, 1993.

2-Allen J. Bard et al., ELECTROCHEMICAL METHODS Fundamentals and

Applications.2001.

3-Nestor Perez, Electrochemistry and Corrosion Science.2004.

Introduction

Two very important ﬁelds of natural science—chemistry and the science of electricity—matured and grew vigorously during the ﬁrst half of the nineteenth century. Electro-chemistry developed simultaneously. From the very beginning,electrochemistry wasnot merely a peripheral ﬁeld but evolved with an important degree of independence,andit also left very signiﬁcant marks on the development of chemistry and of the theory ofelectricity.The ﬁrst electrochemical device was the voltaic pile,built in 1800. For the ﬁrst time,scientists had a suﬃciently stable and reliable source of electric current. Research intothe properties of this current provided the basis for progress in electrodynamics andelectromagnetism. The laws of interaction between electric currents (André-MarieAmpère,1820),of proportionality between current and voltage (Georg Simon Ohm,1827),of electromagnetic induction (Michael Faraday,1831),of heat evolution duringcurrent ﬂow (James Prescott Joule,1843),and others were discovered.Work involving the electrolysis of aqueous solutions of salts and salt melts that wasperformed at the same time led to the discovery and preparation of a number of newchemical elements,such as potassium and sodium (Sir Humphry Davy,1807). Studiesof current ﬂow in solutions (Theodor von Grotthuss,1805) formed the starting pointfor the concept that the molecular structure of water and other substances is polar,andled to the electrochemical theory of the structure of matter formulated by Jons JakobBerzelius (1820). The laws of electrolysis discovered in 1833 by Faraday had an evengreater signiﬁcance for knowledge concerning the structure of matter. During the second half of the nineteenth century,the development of chemical thermodynamicswas greatly facilitated by the analysis of phenomena occurring in electrochemical cellsat equilibrium.Today,electrochemistry is a rigorous science concerned with the quantitativerelations among the chemical,surface,and electrical properties of systems.Electrochemistry has strong links to many other ﬁelds of science. Electrochemicalconcepts proved particularly fruitful for studying and interpreting a number of very important biological processes. Modern electrochemistry has vast applications. Electrochemical processes formthe basis of large-scale chemical and metallurgical production of a number of materials.Electrochemical phenomena are responsible for metallic corrosion,which causesuntold losses in the economy. Modern electrochemical power sources (primary andsecondary batteries) are used in many ﬁelds of engineering,and their productionﬁgures are measured in billions of units. Other electrochemical processes and devicesare also used widely.A variety of deﬁnitions exist for electrochemistry as a subject. Thus,electro-chemistry can be deﬁned as the science concerned with the mutual transformation ofchemical and electrical energy. According to another deﬁnition,electrochemistrydeals with the structure of electrolyte solutions as well as with the phenomenaoccurring at the interfaces between metallic electrodes and electrolyte solutions.These and similar deﬁnitions are incomplete and do not cover all subject areastreated in electrochemistry. By the very general deﬁnition adopted today by mostresearch workers,electrochemistry is the science concerned with the physical andchemical properties of ionic conductors as well as with phenomena occurring at theinterfaces between ionic conductors,on the one hand,and electronic conductors orsemiconductors,other ionic conductors,and even insulators (including gases andvacuum),on the other hand. All these properties and phenomena are studied both underequilibrium conditions,when there is no current ﬂow,and under nonequilibrium conditions,when there is electric current ﬂow in the system. In a certain sense,electrochemistry can be contrasted to electronics and solid-state theory,where theproperties of electronic conductors and electronic or hole-type semiconductors aswell as the phenomena occurring at the interfaces between these materials orbetween the materials and vacuum are examined.This deﬁnition of electrochemistry disregards systems in which nonequilibriumcharged species are produced by external action in insulators:for example,by electricdischarge in the gas phase (electrochemistry of gases) or upon irradiation of liquid andsolid dielectrics (radiation chemistry). At the same time,electrochemistry deals withcertain problems often associated with other ﬁelds of science,such as the structure andproperties of solid electrolytes and the kinetics of ionic reactions in solutions.This book seeks essentially to provide a rigorous,yet lucid and comprehensibleoutline of the basic concepts (phenomena,processes,and laws) that form the subjectmatter of modern theoretical and applied electrochemistry. Particular attention is given to electrochemical problems of fundamental signiﬁcance,yet those oftentreated in an obscure or even incorrect way in monographs and texts. Among theseproblems are some,that appear elementary at ﬁrst glance,such as the mechanism ofcurrent ﬂow in electrolyte solutions,the nature of electrode potentials,and the valuesof the transport numbers in diﬀusion layers.By considering the theoretical and applied aspects of electrochemistry jointly,one can more readily comprehend their intimate correlation and gain a fuller insightinto this science as a whole. The applied part of the book outlines the principles ofsome processes and illustrates their practical signiﬁcance but does not describetechnical or engineering details or the design of speciﬁc equipment,as these can be found in specialized treatises on applied electrochemistry.

As a rule,the mathematical tools used in electrochemistry are simple. However,in books on electrochemistry,one often ﬁnds equations and relations that are quiteunwieldy and not transparent enough. The author’s prime aim is that of elucidatingthe physical ideas behind the laws and relations and of presenting all equations in thesimplest possible,though still rigorous and general,form.There is a great deal of diversity in the terminology and names used for electro-chemical concepts in the literature. It is the author’s aim to introduce uniform termi-nology in accordance with valid standards and recommendations. For a proﬁtablereading of the book and understanding of the material presented,the reader shouldknow certain parts of physics (e.g.,electrostatics),the basics of higher mathematics(diﬀerentiation and integration),and the basics of physical chemistry,particularly chemical thermodynamics.