Microstructure and electrode properties of La0.6Sr0.4Co0.2Fe0.8O3-δ spin-coated on Ce0.8Sm0.2O2−δ electrolyte

Abstract

Fine and uniform La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ powder was synthesized by a glycine-nitrate combustion process. La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ electrodes were prepared on dense Ce 0.8 Sm 0.2 O 2−δ electrolyte substrates using a spin-coating technique by sintering at 900-1,000°C. The electrode properties of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ were investigated by electrochemical impedance spectroscopy and chronopotentiometry techniques with respect to preparation conditions and the resulting microstructures. The results indicate a significant effect of the microstructure on the electrode processes and polarization characteristics. The oxygen adsorption and dissociation process acted as a larger contribution to the overall electrode polarization R p in magnitude compared with the charge transfer process due to relatively low porosity levels of the electrodes. It was detected that the grain size of the electrodes exhibited a crucial role on the electrocatalytic reactivity. At 800°C, the electrode sintered at 950°C attained a polarization resistance of 0.18 Ω cm 2 , an overpotential of 27 mV at a current density of 200 mA cm −2 , and an exchange current density of 308 mA cm −2 .

Electrochemical evaluation of La2NiO4+δ -based composite electrodes screen-printed on Ce0.8Sm0.2O1.9 electrolyte

“…At each temperature, the R p of the composite electrode was lowered by nearly onefold relative to the LN electrode. At 800°C, the composite electrode showed a R p of 0.20 Ω cm 2 , which is very close to those (0.18 Ω cm 2 ) for the LSCF electrodes determined at the same temperature [32,33]. Figure 5 shows the Arrhenius plots of R p for the LN, LN-LSCF, and LN-SDC electrodes.…”

“…The overpotential data suggest a high electrocatalytic activity of the composite electrode, which is consistent with its low polarization resistance determined by EIS analysis. On the other hand, the overpotential value of the LN-LSCF electrode is a little larger than the result (27 mVat 200 mA cm −2 ) of the LSCF electrode on the SDC electrolyte obtained at an identical temperature [32].…”

Property evaluation of Sm 1‐x Sr x Fe 0.7 Cr 0.3 O 3‐δ perovskites as cathodes for intermediate temperature solid oxide fuel cells

“…Among the SmSFCr electrodes investigated, the electrode with x = 0.7 exhibited the lowest R P (0.19 Ω·cm 2 ) and η 200 (30 mV) together with the largest i 0 (257 mA·cm −2 ) at 800°C. These electrocatalytic properties are roughly comparable with the values ( R P = 0.18 Ω·cm 2 , η 200 = 27 mV, and i 0 = 308 mA·cm −2 ) determined at the same temperature for La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3‐δ electrode, a representative composition of LSCF cathodes. On the other hand, these properties are a little inferior to the results ( R P = 0.13 Ω·cm 2 , η 200 = 24 mV, and i 0 = 310 mA·cm −2 at 800°C) of La 0.3 Ca 0.7 Fe 0.7 Cr 0.3 O 3‐δ cathode, a derivative of La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3‐δ perovskite obtained by replacing the strontium with calcium …”

“…The cathodic current polarization curves of the electrodes were measured using the chronopotentiometry technique with 25 current density steps from 10 to 250 mA·cm −2 . The details of the chronopotentiometry measurement have been described elsewhere …”

Cu-doped Nd0.6Sr0.4Co1−xCuxO3−δ (x = 0, 0.05, 0.1, 0.15, 0.2) as the cathode for intermediate-temperature solid oxide fuel cells

“…At 800 °C, the ASR value of NSCC 0.1 is 0.108 Ω cm 2 , showing a lower ASR than La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3− δ (0.18 Ω cm 2 ) and better electrochemical performance. 34 …”