Strontium and iron-doped barium cobaltite prepared by solution combustion synthesis: exploring a mixed-fuel approach for tailored intermediate temperature solid oxide fuel cell cathode materials

Abstract

Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-d (BSCF) powders were prepared by solution combustion synthesis using single and double fuels. The effect of the fuel mixture on the main properties of this well-known solid oxide fuel cell cathode material with high oxygen ion and electronic conduction was investigated in detail. Results showed that the fuel mixture significantly affected the area-specific resistance of the BSCF cathode materials, by controlling the oxygen deficiency and stabilizing the Co 2? oxidation state. It was demonstrated that high fuel-to-metal cations molar ratios and high reducing power of the combustion fuel mixture are mainly responsible for the decreasing of the area-specific resistance of BSCF cathode materials. Moreover, a new metastable monoclinic phase with Ba 0.5 Sr 0.5 CO 3 composition was discovered in the as-burned BSCF powders, enlarging the existing information on the BSCF phase formation mechanism. Keywords Solution combustion synthesis Á Intermediate temperature solid oxide fuel cells Á Cathode materials Á Combustion fuel mixture Á BSCF Á Perovskite-type compounds Electronic supplementary material The online version of this article (

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La0.6Sr0.4Co0.2Fe0.8O3-δversus Ba0.5Sr0.5Co0.8Fe0.2O3-δ

“…This peak, which was not observed in not-aged BSCF cathodes (Fig. 2), is compatible with a rhombohedral Ba 3 Co 10 O 17 -like structure with low symmetry 49,64,90 and could be related to the lamellar-phase, which developed during the long annealing time of the tested sample (800 h).…”

“…49 Briefly, the corresponding metal nitrates were mixed with sucrose (Eridania) -polyethylene glycol (PEG, MW 20000, Fluka Chemical) fuel mixture in a 1:1 molar ratio of sucrose to PEG unit. The sucrose-to-metal cation molar ratio was set to 2, whereas the reducers-to oxidizers ratio was regulated by the addition of ammonium nitrate and set to 2 for LSCF and to 3 for BSCF, according to a detailed study of the best synthesis conditions.…”

“…The as-burned powders were fired for 5 h at 1273 K (LSCF), or at 1223 K (BSCF), in order to obtain the full crystallization of the perovskite-type phase. 49 The LSCF and BSCF powders were mixed with α-terpineol (techn. 90%, Sigma Aldrich) and manually ground in a mortar to obtain a suspension suitable for deposition.…”

“…46,47 Considering oxygen vacancies as charged species inside the electrode volume, C chem is a quantitative measure of the capability of the material of storing such charges. 48 In this paper, a preparation method based on solution combustion synthesis, already developed in a previous paper for a BSCF composition, 49 was successfully applied to produce both LSCF and BSCF nanopowders with suitable conduction properties. A comparison of the two materials was carried out, testing them as cathodes in an SDC-supported system, to investigate any effect on their performance and chemical stability due to the application of an LSM-infiltrated discrete layer.…”

Oxide material synthesis by combustion of organic-inorganic compositions

“…Such experiments have been implemented, in particular, by synthesis of calcium zirconate CaZrO 3 [112,118] as a practically important material for producing dielectric and refractory ceramics, a component of the photocatalytic and luminescent systems, solid electrolytes with different conductivity. Calcium metazirconate was synthesized by the SCS method [203], using various organic reagents such as β-alanine [204], citric acid [205,206] or citric acid with urea [207], glycine [138,208] for the combustion reaction. To determine the combustion parameters in [112,118], the synthesis was carried out in glycine-nitrate systems.…”