The oxygen partial pressure in solid oxide electrolysis cells with multilayer electrolytes

TitleThe oxygen partial pressure in solid oxide electrolysis cells with multilayer electrolytes
Publication TypeJournal Article
Year of Publication2021
AuthorsZhang Q, Liu Q-Y, Park B-K, Barnett S, Voorhees P
JournalActa Materialia
Volume213
Pagination116928
ISSN1359-6454
KeywordsDiffuse interface model, Multilayer electrolyte, Oxygen partial pressure, solid oxide electrolysis cell
Abstract

A number of degradation mechanisms have been observed during the long-term operation of solid oxide electrolysis cells (SOEC). Using an electrolyte charge carrier transport model and a diffuse interface treatment for a multilayer electrolytes, we quantify the oxygen potentials across the electrolyte and thereby provide insights into these degradation mechanisms. Our model describes the transport of charge carriers in the electrolyte when the oxygen partial pressure is extremely low by accounting for the spatial variation of the concentration of oxygen vacancies in the electrolyte which is closely related to the degradation of the SOEC near the interface of hydrogen electrode and electrolyte. Moreover, we identify four quantities that characterize the distribution of oxygen partial pressure in the electrolyte, which are directly related to the degradation mechanisms in the electrolyte as well, and give analytical estimates for them. These analytical expressions provide guidance on the parameters that need to be controlled to suppress the degradation observed in the electrolyte.

URLhttps://www.sciencedirect.com/science/article/pii/S1359645421003086
DOI10.1016/j.actamat.2021.116928