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

Abstract

La 2 NiO 4+δ , 60 wt.% La 2 NiO 4+δ -40 wt.% La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ , and 60 wt.% La 2 NiO 4+δ -40 wt.% Ce 0.8 Sm 0.2 O 1.9 electrodes were prepared from fine powders on dense Ce 0.8 Sm 0.2 O 1.9 electrolyte substrates by screenprinting technique. Electrochemical impedance spectroscopy and chronopotentiometry techniques were employed to evaluate the electrochemical properties of the composite electrodes in comparison with the La 2 NiO 4+δ electrode. For the three electrodes, main electrode processes were resolved to be charge-transfer at the electrode/electrolyte interface and oxygen exchange on the electrode surface. The contribution of the surface oxygen exchange process was detected to be dominant for the overall electrode polarization. The addition of Ce 0.8 Sm 0.2 O 1.9 into La 2 NiO 4+δ was favorable for the charge transfer process whereas it was undesired for the surface oxygen exchange process. On comparison, adding La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ into La 2 NiO 4+δ was found to benefit both the two electrode processes. The La 2 NiO 4+δ -La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ composite electrode showed optimum electrochemical properties among the three electrodes. At 800°C, the composite electrode achieved a polarization resistance of 0.20 Ω cm 2 , an overpotential of 45 mV at a current density of 200 mA cm −2 , together with an exchange current density of ∼200 mA cm −2 .

Novel La 2 NiO 4+δ and La 4 Ni 3 O 10−δ composites for solid oxide fuel cell cathodes

“…This compares favourably with literature data and is believed to be the best performance for electrodes of this class. These ASR values are lower than that quoted for L2N1 [27,28]; a copper-doped phase La 2 Ni 0.6 Cu 0.4 O 4þd [26]; L3N2 [11]; and the various LaeNi electrodes discussed in a recent review [2]. Fig.…”

Advances in Cathode Materials for Solid Oxide Fuel Cells: Complex Oxides without Alkaline Earth Metal Elements

“…[ 278 ] The performance of a cell with a composite electrode composed of 80 facilitate the charge transfer process. [ 290 ] In a following study, Pérez-Coll et al found that the polarization resistance of pure La 2 NiO 4 electrode reduced substantially once a DC cathodic current polarization was applied, and the performance became comparable to the La 2 NiO 4 -SDC composite electrode, which did not show an apparent positive performance improvement under polarization. [ 280 ] But the performance improvement from the polarization disappeared once the polarization was removed.…”

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

“…SmSFCr electrodes were prepared onto the electrolyte substrates by a screen printing technique. The fabrication procedure, configuration, and geometrical factors of the half cells were almost identical to those described in our earlier publication except for varied working electrodes …”