engleski

The role of redox mixed phases OXx(Cnred)1-x in solid state electrochemical reactions and the effect of miscibility gaps in voltammetry

A basic analysis is performed to establish the interrelations between the equilibria existing when one solid phase ox is transformed into another solid phase Cnred while both are in close contact with a solution containing both redox forms in the dissolved state. The transformation of the above solid phases by electrochemical reactions can be understood when the intermediate formation of mixed phases between ox and Cnred is taken into account. Such a description allows solid state electrochemical reactions to be modeled for the case of an infinite miscibility of oxidized and reduced solid compounds as well as for the case of systems with miscibility gaps. It is shown that miscibility gaps will lead to a splitting of both the anodic and cathodic voltammetric peaks and also to a distinc separation of the anodic and chatodic reactions on the potential scale in voltammetric experiments. This phenomenon can be called an immiscibility polarization.

solid phase; redox; transformation; miscibility; voltammetry

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