Rate limiting steps of the porous La0.6Sr0.4Co0.8Fe0.2O3−δ electrode material

Microstructure and reactivity effects on the performance of Nd2NiO4+δ oxygen electrode on Ce0.9Gd0.1O1.95 electrolyte

“…They obtained at 700 C similar Lc values for both oxides. However, previous studies on cobaltites indicate that no ratelimiting step by surface control was observed for electrodes with quite different geometries, obtained either from powders [35] or sputtered films [42]. The microstructure of powders of reference [33] is similar to that of our NNO-HMTA samples.…”

“…The C values are around 10 À1 F cm À2 , which are between those associated to O 2 gas diffusion into the porous electrode (n ¼ 1) and dissociative adsorption process (n ¼ 0.5). This intermediate n value should suppose a rate-limiting step given by a convolution of dissociative adsorption and gaseous diffusion as observed by other authors [35]. It is probable that the dissociative adsorption process has been always present for the NNO-SSR sample at other temperatures and higher pO 2 values.…”

Electrode/Electrolyte Interphase Characterization in Solid Oxide Fuel Cells

“…The limiting steps are O 2-transport into the cathode bulk and Oxygen gas-phase diffusion. This reaction path was previously proposed by Grunbaum et al for a La0.6Sr0.4Co0.8Fe0.2O3-δ cathode with submicrometric grains [55]. The ASRRCPE related to Oxygen gas-phase diffusion is similar for both cathodes [8], while ASRw related to Oxygen ion transport into cathode bulk is more than two orders of magnitude lower for the nanostructured cathode (see Figure 8) at temperatures lower than 600°C.…”

Stabilization of the cubic perovskite in the system La 1−x Ba x Co 1−y Fe y O 3−δ (0.7 ≤ x ≤ 0.9) and its electrochemical performance as cathode materials for intermediate-temperature solid oxide fuel cells

“…For the low frequency polarization resistance (R LF ), the linear fit of the experimental data yield a slope value of n wÀ1, which is consistent with a ratelimiting process controlled by the oxygen gas phase diffusion in the porous phase of the electrode [30,34,35]. This conclusion is also supported by the capacitance values ranging between 1.4 and 6 F cm À2 and the weak dependence on temperature of the LF impedance arc expected for this contribution [36,37].…”