A multistep model for the kinetic analysis of the impedance spectra of a novel mixed ionic and electronic conducting cathode

A detailed kinetic model for the reduction of oxygen on LSCF-GDC composite cathodes

“…Apart of fully phenomenological descriptions based on RC and CPE elements, the introduction of Gerischer elements provides more reliable physical meaning: nonetheless, extrapolation of the results is difficult and mechanistic elucidation is limited. A second approach entails the application of physical models, wherein fundamental equations of charge, mass and energy conservation are solved [10,16,[19][20][21][22][23][24][25][26][27]. Depending on the assumptions and on the dimensionality of the problem, several parameters can be accounted for in terms of microstructure, operative conditions, kinetics and thermodynamics.…”

Copper Doped La0.8Sr1.2FeO4 Ruddlesden‐Popper SOFC Cathode: Synthesis, Characterization and Model Analysis

“…With respect to the possibility of the alternative 2PB pathway, a similar analysis with an appropriate 1D model was carried out [57], which could not successfully describe the insensitivity on the particle diameter, due to a much stronger dependency on the a v term. Specifically, the insensitivity to the particle size resulted from a balance between the reduced impact of the TPB extension and the different activation energies of the electronation step.…”

“…Full details on the numerical solution and the complete list of the assumptions and of the equations can be found in [57]. Full details on the numerical solution and the complete list of the assumptions and of the equations can be found in [57].…”

“…Overall, the simulations showed that a TPB-based route could reasonably explain the observations and clarify the information provided by the ECM. With respect to the possibility of the alternative 2PB pathway, a similar analysis with an appropriate 1D model was carried out [57], which could not successfully describe the insensitivity on the particle diameter, due to a much stronger dependency on the a v term. As a matter of fact, the ORR behavior of the LSCF sample appeared to be governed by the surface diffusion of oxygen, instead of the lattice diffusion: the active area for charge transfer was limited to the contact with the electrolyte phase.…”

“…The model applied for the analysis of the EIS spectra was derived from a multistep model previously validated. Full details on the numerical solution and the complete list of the assumptions and of the equations can be found in [57]. The original model simulates the impedance spectra in the time domain by accounting for the gas diffusion inside the electrode pores, and for the solid state diffusion of oxygen vacancies inside the bulk of the cathodic material: the ORR is described via a detailed kinetic scheme where the 2PB pathway prevails.…”