Cu-Ce0.8Gd0.2O2-delta materials as SOFC electrolyte and anode

abstract

Co-sintering of Cu-CGO cermet anodes on CGO (Ce0.8Gd0.2O2-delta) electrolyte was conducted at low temperature (1000 degreesC) by introducing small amounts (2 mol.%) of CuO sintering aid to the electrolytic CGO. The Cu-CGO anodes with Cu contents from 20-50 vol.% were prepared by combustion synthesis followed by sintering and reduction. Symmetrical anode/ electrolyte/anode assemblies of Cu-GCO/CGO/Cu-CGO were fabricated by manually depositing the anode combustion powder on a green substrate of the 2 mol% CuO-containing CGO, followed by co-pressing and co-sintering of the assembly at 1000 degreesC. The low-temperature sintered CGO is submicron with 95-99% relative density. CuO addition has no significant effect on either the total or ionic conductivity of the electrolyte, but p-type conduction in the temperature range, 900-1200 degreesC, is 25 times higher than that of undoped CGO. Oxygen-ion transference numbers of the Cu-containing CGO lie in the range 0.89-0.99, as determined by the modified e.m.f. technique under an oxygen/air potential gradient. The activation energy for ionic conduction, 83 kJ mol(-1), is significantly lower than that for p-type electronic transport, 140 kJ mol(-1).

keywords

OXIDE FUEL-CELLS; CERIA SOLID-SOLUTIONS; DOPED CERIA; CONDUCTION

subject category

Chemistry; Electrochemistry; Physics

authors

Fagg, DP; Mather, GC; Frade, JR

our authors

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