Modeling the impedance response and steady state behaviour of porous CGO-based MIEC anodes

Abstract

The SOFC MIEC anode model enables an appropriate understanding of the complex physico-chemical processes and microstructure effects and thus provides a basis for a systematic materials optimization.

Electrochemical Performance of SrFeO3−δ for Application as a Symmetric Electrode in Solid Oxide Fuel Cells

“…37 This is also evident from the fairly high capacitance value of 1.3 F•cm −2 and its dependency on the p H2 as given in Table 2. 37,38 Moreover, the electrochemical reaction occurring at the SFO/pore interface depends on the simultaneous conduction of electrons and oxygen vacancies inside the SFO electrode. 10 Thus, both the chemical capacitance and electrochemical reaction strongly depend on the temperature and oxygen partial pressure.…”

“…In the present work, the m value for the low-frequency arc is 0.504, suggesting an electrochemical process. Based on the observed temperature and pH 2 dependency, the low-frequency arc can be attributed to surface reaction resistance and chemical capacitance processes . As SFO is a mixed ionic–electronic conductor, it is likely to possess chemical capacitance, which describes the ability to store charges in the bulk of the electrode due to oxygen non-stoichiometry .…”

“…therefore, can be assigned to the oxygen-ion transfer across the SFO/GDC interface. 17, 37 The capacitive component in the high-frequency arc, which is found to be independent of p H2 (except in 25 vol % H 2 /N 2 ), corresponds to the capacitance associated with the SFO/GDC interface.…”

“…Based on the observed temperature and pH 2 dependency, the low-frequency arc can be attributed to surface reaction resistance and chemical capacitance processes. 37 As SFO is a mixed ionic−electronic conductor, it is likely to possess chemical capacitance, which describes the ability to store charges in the bulk of the electrode due to oxygen nonstoichiometry. 37 This is also evident from the fairly high capacitance value of 1.3 F•cm −2 and its dependency on the p H2 as given in Table 2.…”

“…37 As SFO is a mixed ionic−electronic conductor, it is likely to possess chemical capacitance, which describes the ability to store charges in the bulk of the electrode due to oxygen nonstoichiometry. 37 This is also evident from the fairly high capacitance value of 1.3 F•cm −2 and its dependency on the p H2 as given in Table 2. 37,38 Moreover, the electrochemical reaction occurring at the SFO/pore interface depends on the simultaneous conduction of electrons and oxygen vacancies inside the SFO electrode.…”