Mechanism of oxygen electrode delamination in solid oxide electrolyzer cells

• Published in: International journal of hydrogen energy Vol. 35; no. 18; pp. 9527 - 9543
• Main Author: Virkar, Anil V.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.09.2010; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Delaminating; Delamination; Electrodes; Electrolysis; Electrolytes; Electrolytic cells; Electronics; Energy; Exact sciences and technology; Fuels; Hydrogen; Mathematical models; Non-equilibrium thermodynamics; Oxides; Oxygen electrode delamination; Solid oxide electrolyzer cell; Non-equilibrium thermodynamics; Oxygen electrode delamination; Solid oxide electrolyzer cell; Electrolysis; Degradation; Thermodynamics; Hydrogen; Chemical potential; High pressure
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2010.06.058

An electrochemical model for degradation of solid oxide electrolyzer cells is presented. The model is based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic non-equilibrium. It is shown that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, μ O 2 , within the electrolyte. The μ O 2 within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just near the oxygen electrode/electrolyte interface, leading to oxygen electrode delamination. These predictions are in accord with the reported literature on the subject. Development of high pressures may be avoided by introducing some electronic conduction in the electrolyte.