Preparation via a solution method of La0.2Sr0.25Ca0.45TiO3 and its characterization for anode supported solid oxide fuel cells

Abstract

is a carefully selected composition to provide optimal ceramic and electrical characteristics for use as an anode support in solid oxide fuel cells. In this study we focus on the process optimization and characterization of A-site deficient perovskite, La 0.2 Sr 0.25 Ca 0.45 TiO 3 (LSCT A-), powders prepared via a solution method to be integrated into the SOFC anode supports. A Pechini method has been applied to successfully produce single phase perovskite at 900 C. Processing conditions have been modified to yield a powder that displays a similar sintering profile to commercial yttria stabilised zirconia. The conductivity behavior of porous bodies under redox has been investigated showing a 2 stage process in both oxidation and reduction cycling that exhibits strong reversibility. For the reduction process, addition of impregnated ceria reduces the onset delay period and increases the apparent rate constant, k values, by 30-50% for both stages. The addition of ceria had less influence on the oxidation kinetics, although the conductivity values of both oxidised and reduced porous bodies were enhanced.

Synthesis and characterization of B-site doped La 0.20 Sr 0.25 Ca 0.45 TiO 3 as SOFC anode materials

“…All materials were prepared by modified Pechini method described in detail previously [11]. Room temperature powder X-ray diffraction (XRD) was performed …”

“…The equilibrium value could not be reached even after 50 hours of reduction but the increase in conductivity value was gradual as time progressed. These two stages might be related to the fast removal of oxygen from the surface of the perovskite that is followed by a slow diffusion into the bulk of the micron size grains [11,18,19].…”

“…Furthermore, the same composition was tested as an anode in fuel cell conditions where good performance was achieved [10]. Recently we have reported the solution phase synthesis of LSCT A- [11].…”

Modified strontium titanates: from defect chemistry to SOFC anodes

“…. 53 The porosity and lack of pre-reduction results in a drop of conductivity of approximately an order of magnitude, but constant conductivity values are obtained on redox cycling between pO 2 ¼ 10 À17 to 0.21 atm, with no sign of sample degradation or mechanical failure. The authors further noticed a marked increase in the redox kinetics, when impregnating the bars with ceria.…”

La and Ca-Doped A-Site Deficient Strontium Titanates Anode for Electrolyte Supported Direct Methane Solid Oxide Fuel Cell

“…Ti 4+ /Ti 3+ redox couple in the reducing atmosphere can accept electrons from hydrocarbon or H2 and promote dissociation. Oxygen-2p orbital and the empty conduction band from titanium-3d orbitals constitute the electronic energy band of 16,19,20 . It is shown that presence of Ni and CeO2 in LSCTA-backbone decreases the polarization losses and provides the stable performance of the cell during redox cycling 21 .…”