New families of Mn+-doped SrCo1−xMxO3−δ perovskites performing as cathodes in solid-oxide fuel cells. (14th September 2015)

• Record Type: Journal Article
• Authors: Cascos, V.; Troncoso, L.; Alonso, J.A.
• Is Part Of: International journal of hydrogen energy. Volume 40:Number 34(2015)
• Page Start: 11333
• Page End: 11341
• Publication Date: 2015-09-14
• Subjects: Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.03.134
• Languages: English
• ISSNs: 0360-3199

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">We have investigated the effect of M = Ti<sup>4+</sup> and V<sup>5+</sup> doping on the crystal structure and on the thermal, electrical, and electrochemical properties of SrCo<sub>1−x</sub>M<sub>x</sub>O<sub>3−δ</sub> (x = 0.03 and 0.05) perovskite oxides performing as cathodes in solid oxide fuel cells (SOFC). The characterization of these materials included x-ray (XRD) and neutron powder diffraction (NPD) measurements. The introduction of Ti<sup>4+</sup> and V<sup>5+</sup> replacing Co in SrCoO<sub>3−δ</sub> leads to the stabilization of a tetragonal perovskite superstructure at room temperature with a = a<sub>0</sub>, c = 2a<sub>0</sub> (a<sub>0</sub>≈ 3.9 Å) defined in the <italic>P4/mmm</italic> space group, containing two inequivalent Co positions. Flattened and elongated (Co, M)O<sub>6</sub> octahedra alternate along the c axis sharing corners in a three-dimensional array (3C-like structure). The thermal expansion coefficients of SrCo<sub>0.95</sub>Ti<sub>0.05</sub>O<sub>3−δ</sub> and SrCo<sub>0.97</sub>V<sub>0.03</sub>O<sub>3−δ</sub> have been measured between 25 and 850 °C. The electrical conductivity at the SOFCs working temperatures (650–850 °C) seems to be sufficient to yield a good performance in IT-SOFC; the polarization resistance in symmetrical cells is as low as 0.016 Ω cm<sup>2</sup> at 850 °C for M = Ti. In single test cells these materials generated a maximum power of 824 mW/cm<sup>2</sup> at 850 °C with pure H<sub>2</sub> as a fuel. This good performance make these systems promising candidates as cathode materials in SOFC.</p> </sec> </abstract>