Oxygen transport and electrochemical activity of La2NiO4-based cathode materials
authors Kharton, VV; Yaremchenko, AA; Tsipis, EV; Frade, JR
editors Singhal, SC; Dokiya, M
nationality International
journal SOLID OXIDE FUEL CELLS VIII (SOFC VIII)
keywords SOLID-SOLUTIONS; PERMEABILITY
abstract Mixed-conducting La2Ni1-xMxO4+delta (M= Co, Cu; x= 0-0.20) with K2NiF4-type structure possesses significant p-type electronic conductivity and oxygen permeability in combination with relatively low thermal expansion coefficients, (12.5-13.5)x10(-6) K-1, which are compatible with that of La(Sr)Ga(Mg)O3-delta (LSGM) solid electrolytes. These phases are of interest as potential cathode materials for intermediate-temperature solid oxide fuel cells (SOFCs). Incorporating copper into the nickel sublattice was found to decrease the sintering temperature needed to achieve sufficient mechanical strength of highly porous electrode layers. As for other nickelates, oxygen permeation through La2Ni1-xMxO4+delta ceramics is limited by both bulk ionic conductivity and oxygen surface exchange. The results on overpotential-current dependencies of La2Ni0.8Cu0.2O4+delta electrodes in contact with LSGM suggest that the electrochemical reaction is essentially localized on triple-phase boundary and/or cathode surfaces. This leads to a moderate performance of La2NiO4+delta-based cathodes at 873-1073K, similar to that of perovskite-type electrode materials, such as La(Sr)Fe(CO)O3-delta and LaFe(Ni)O3-delta, despite higher ionic conductivity of nickelates.
publisher ELECTROCHEMICAL SOCIETY INC
isbn 1-56677-377-6
year published 2003
volume 2003
issue 7
beginning page 561
ending page 570
web of science category Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary
subject category Electrochemistry; Energy & Fuels; Materials Science
unique article identifier WOS:000186761000067

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