Sol–gel synthesis, X-ray photoelectron spectroscopy and electrical conductivity of Co-doped (La, Sr)(Ga, Mg)O3−δ perovskites
✍ Scribed by Riccardo Polini; Alessia Falsetti; Enrico Traversa; Oliver Schäf; Philippe Knauth
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 553 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0955-2219
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✦ Synopsis
La 0.8 Sr 0.2 Ga 0.8 Mg 0.2-x Co x O 3-δ (LSGMC) powders containing different amounts of Co (x = 0.05 and 0.085) were prepared by a citrate sol-gel method. The powders were used to prepare highly phase-pure LSGMC sintered pellets with controlled composition and fractional densities larger than 95%. For the first time, LSGMC materials were subjected to X-ray photoelectron spectroscopy (XPS) characterization. XPS data confirmed the presence of the dopants in the material and allowed to identify two different chemical states for Sr 2+ and oxygen, both related to the oxygendeficient perovskite structure of LSGMC. The conductivity of LSGMC sintered pellets containing different amounts of Co ions in the B sites of the perovskite lattice was assessed by electrochemical impedance spectroscopy (EIS) in the 250-750 • C temperature range. Conductivity values and apparent activation energies were in good agreement with previously published data referring to materials with same composition, but prepared by solid-state route. Therefore, the physicochemical and electrochemical characterization clearly demonstrated the ability of sol-gel methods to produce high-purity Co-doped LSGM perovskites, which represent promising solid electrolytes for intermediate-temperature SOFCs.