A new scandium and niobium co-doped cobalt-free perovskite cathode for intermediate-temperature solid oxide fuel cells

Guihua Chen, Yong Wang, Jaka Sunarso, Fengli Liang and Huanping Wang

Energy, 2016, vol. 95, issue C, 137-143

Abstract: In exploring new cobalt-free perovskite oxide cathodes for intermediate temperature SOFCs (solid oxide fuel cells), Sc and Nb co-doped SrFeO3-based perovskite, SSNF (SrSc0.175Nb0.025Fe0.8O3−δ) was synthesized. Powder X-ray diffraction, high resolution transmission electron microscopy and SAED (selected area electron diffraction) showed that SSNF crystallized in the tetragonal space group P4/mmm (#123) with lattice parameters of a = 3.912 Å and c = 7.794 Å. Upon heating from 400 °C to 1000 °C, the oxygen non-stoichiometry (δ) of SSNF increased from 0.19 to 0.47, concurrent with a decrease in the average valence state of iron from 3.73 to 3.03. The electrical conductivity of SSNF followed semi-conducting thermal dependence behavior, with values of 3.7–9.4 S cm−1 at 350–750 °C. O2-TPD (oxygen temperature programmed desorption) indicated the onset of Fe4+ reduction at ∼500 °C. SSNF exhibited a low thermal expansion coefficient value of 16.2 × 10−6 K−1 (70–900 °C), as anticipated by excluding cobalt from the perovskite lattice. SSNF was relatively inert to the SDC (Sm0.2Ce0.8O1.9) electrolyte up to 1000 °C. These features, and its low ASR (area specific resistance) of 0.236 Ω cm2 at 600 °C, denote the potential of SSNF and the opportunity to create new structures with improved performance through a co-doping strategy.

Keywords: Cathode; Cobalt-free; Oxygen reduction reaction; Perovskite; Solid oxide fuel cell (search for similar items in EconPapers)
Date: 2016
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Citations: View citations in EconPapers (4)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:95:y:2016:i:c:p:137-143

DOI: 10.1016/j.energy.2015.11.061

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