A thermodynamic perspective on electrode poisoning in solid oxide fuel cells

A critical challenge to the commercialization of clean and high-efficiency solid oxide fuel cell(SOFC) technology is the insufficient stack lifespan caused by a variety of degradation mechanisms, which are associated with cell components and chemical feedstocks.Cell components related degradation refers to thermal/chemical/electrochemical deterioration of cell materials under operating conditions,whereas the latter regards impurities in feedstocks of oxidant(air) and reductant(fuel). This article provides a thermodynamic perspective on the understanding of the impurities-induced degradation mechanisms in SOFCs. The discussion focuses on using thermodynamic analysis to elucidate poisoning mechanisms in cathodes by impurity species such as Cr, CO2, H2O, and SO2and in the anode by species such as S(or H2S), SiO2, and P2(or PH3). The author hopes the presented fundamental insights can provide a theoretical foundation for searching for better technical solutions to address the critical degradation challenges.