Low-temperature preparation and investigation of electrochemical properties of SFM/CGO composite electrode

Abstract

Solid Oxide Cells (SOC), as a key energy-conversion technology, require sintering at temperatures exceeding 1200 °C, which tend to coarsen the structure of the fuel electrode. Nanostructured electrodes with high surface areas can help to decrease the electrode resistance and facilitate the operation of the SOC stacks at low temperatures with current collectors made from cheaper steel types. In this paper, we demonstrate and carefully evaluate a novel low-temperature manufacturing method for nanostructured Strontium Iron Molybdenum Oxide (SFM)/Gadolinium Doped Ceria (CGO) composite electrodes. The composite electrodes are applied on both sides of a Zr-based electrolyte with CGO barrier layers and sintered at 800 °C for 3 h in a 5% H2/N2 atmosphere. The preparation parameters, thermal behavior, and electrode microstructure are studied to improve electrochemical performance. Based on the fitting of Nyquist plots, the electrochemical performance is mainly limited by two reactions in series at low frequency, in the 0.08–1 Hz and 1–50 Hz ranges. The electrode polarization resistance is almost constant at 1.24 Ω cm2 for 110 h at 750 °C in 60 vol% CO/CO2.