Mixed ionic-electronic conductive MIEC

Sunarso J, Baumann S, Serra JM, Meulenberg WA, Liu S, Lin YS, and Diniz da Costa JC. Mixed ionic-electronic conducting (MIEC) ceramic-based membranes for oxygen separation. J. Membr. Sci. 2008 320 13-41. 

Figure 3.2 Schematic illustration of oxygen permeation through mixed ionic-electronic conducting (MIEC) membranes when air is used as the feedstock stream (Zhu Yang, 2011). Reprinted with permission hy Elsevier.

Sunarso J, Mixed Ionic-electronic Conducting (MIEC) Ceramic-based Membranes for Oxygen Separation, Journal of Membrane Science, 320,13-41 (2008). 

Electrode reactions involve charge transfer as a fundamental step, wherein a neutral species is converted into an ion, or an ion is converted into a neutral species. Both reactions thus involve electron transfer. At the cathode, the charge transfer reaction involves the conversion of an oxygen molecule into oxide ions. The electrodes in solid state electrochemical devices may either be purely electronic conductors, or may exhibit both ionic and electronic conductivity (the so-called mixed ionic electronic conduction, MIEC). In addition, the electrodes may be either single phase or composite, two-phase. For the purposes of illustration, in what follows we will examine the overall cathode reaction in a system with a single phase, purely electronically conducting electrode. 

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