Stability of La1−xAxMnO3−z (A=Ca, Sr) as cathode materials for solid oxide fuel cells

Takeda, Youji; Sakaki, Yoshinori; Ichikawa, Takayuki; Imanishi, Nobuyuki; Mori, M.; Mori, Nanako; Abe, Toshio

doi:10.1016/0167-2738(94)90156-2

Cited by 69 publications

(31 citation statements)

References 4 publications

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“…Materials with very low mixed conductivity have been considered, in order to ensure that charge transfer processes are mainly localised at the Three Phase Boundary points (TPB). In particular, the cathode is composed of a Lanthanum Strontium Manganite (LSM) and Yttria-stabilized Zirconia (YSZ) mixture, the most conventional and stable couple of materials for application in SOFCs, due to their chemical stability and compatibility [13][14][15]. New experimental results are presented which extend previously published data [16].…”

Section: Introductionmentioning

confidence: 81%

Morphology and electrochemical activity of SOFC composite cathodes: I. experimental analysis

et al. 2008

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This paper describes the first part of an experimental and theoretical study performed on composite Lanthanum Strontium Manganite (LSM) and Yttria-stabilized Zirconia (YSZ) electrodes. Cathode electrocatalytic activity was investigated using different cell configurations and carrying out potentiodynamic polarisation and electrochemical impedance spectroscopy measurements (EIS). Measurements were carried out at different oxygen partial pressures, overpotentials, temperatures and electrode geometries. In order to identify the main steps involved in cathodic oxygen reduction, the NLLS-Fit procedure was used. The results for different cell geometries agree with each other, suggesting a transition in the overall reaction mechanism, from charge transfer to mass transfer control, at a critical temperature of about 750 A degrees C. The experimental results also show a remarkable effect of electrode thickness on the overall reaction rate, throughout the temperature range tested. A grey level gradient along the thickness of the thicker electrodes were detected by analyzing microscopic images of the cells. These results, together with electrochemical measurements on cathodes with different thickness, confirm that morphology plays a key role in determining the performance of Solid Oxide Fuel Cells (SOFC) composite cathodes

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Section: Introductionmentioning

confidence: 81%

Morphology and electrochemical activity of SOFC composite cathodes: I. experimental analysis

et al. 2008

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“…Furthermore, some role can be played by the deficiency of Ln 3+ cations in the Ln-Mn nanocomposite as compared to the ratio Ln 3+ : Mn = 1 : 1 necessary for the formation of the perovskite with the stoichiometric composition of cations. Cation vacancies in the sublattice A of the perovskite phase lead to an increase in the concentration of Mn 4+ cations in the sublattice B, thus increasing the electrical conductivity [27]. Despite the dilution of the perovskite phase by the fluorite phase with a considerably lower electrical conductivity in the Ln-Mn system [3,5], the total electrical conductivity extrapolated to that at a temperature of 1000°C (~15 S -1 cm -1 ) is close to those characteristic of the porous materials La(Ca,Sr)MnO 3 (~50-70 S -1 cm -1 ) [3,17] and Gd-Sr(Ca)MnO 3 (10-30 S -1 cm -1 ) [26].…”

Section: Total Electrical Conductivitymentioning

confidence: 99%

Synthesis and properties of nanocomposites with mixed ionic-electronic conductivity on the basis of oxide phases with perovskite and fluorite structures

et al. 2007

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Nanocomposites consisting of phases with fluorite (doped CeO 2 ) and perovskite (LaMnO 3 , GdMnO 3 ) structures are synthesized using the method of ester polymeric precursors (the Pechini method) and two sources of rare-earth elements ( Ln ), such as pure cerium and gadolinium salts or a commercial mixture of rare-earth carbonates containing La, Ce, Pr, Nd, and Sm cations. The genesis of the nanocomposite structure as a function of the sintering temperature is investigated using X-ray diffraction and electron microscopy. It is revealed that the genesis of the nanocomposite structure is governed, in many respects, by the fact that the decomposition of the ester polymeric precursor leads to the formation of a metastable phase, namely, a fluoritelike solid solution based on ceria with an excess concentration of the cations Ln 3+ ( Ln 3+ = La 3+ , Pr 3+ , Nd 3+ , Sm 3+ ) as compared to the equilibrium concentration. As a result, the perovskite phase (identified by X-ray diffraction analysis) is formed only after the subsequent annealing at temperatures higher than 800 ° C, when Ln 3+ cations escape from particles of the solid solution. It is demonstrated that, at annealing temperatures of up to 1100 ° C, particles of both phases have nanometer sizes and are characterized by a uniform spatial distribution necessary for percolation. The nanocomposites possess a high total electrical conductivity and a high mobility of lattice oxygen. The reduction rate of the nanocomposites with hydrogen or methane is higher than the reduction rate of the individual phases. The characteristics of the nanocomposites prepared from the commercial mixture of rare-earth carbonates are better than those of the samples synthesized from the pure salts.

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“…The ease with which oxygen vacancies form is strongly influenced by the Sr content [19]. The influence of the cation vacancy on the transport properties of these materials has led to a study of the defects in these materials, such as LMO, and the effect of substitutions on the lanthanide site [20]. DeSouza et al found that in both rhombic and rhombohedral structures, nonstoichiometry leads to the formation of vacancies on both cation positions, presenting a tendency toward the formation of vacancies [21].…”

Section: Cathode Materialsmentioning

confidence: 99%

Designing Perovskite Oxides for Solid Oxide Fuel Cells

Larramendi¹,

Ortiz‐Vitoriano²,

Bautista³

et al. 2016

Perovskite Materials - Synthesis, Characterisation, Properties, and Applications

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Perovskite-type oxides with the general formula ABO 3 have been widely studied and are utilized in a large range of applications due to their tremendous versatility. In particular, the high stability of the perovskite structure compared to other crystal arrangements and its ability, given the correct selection of A and B cations, to maintain a large oxygen vacancy concentration makes it a good candidate as electrode in solid oxide fuel cell (SOFC) applications. Utilizing this novel structure allows the engineering of advanced, effective electrolytes for such devices. This review details the development of current state-of-the-art perovskite-type oxides for solid oxide fuel cell (SOFC) applications.

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Stability of La1−xAxMnO3−z (A=Ca, Sr) as cathode materials for solid oxide fuel cells

Cited by 69 publications

References 4 publications

Morphology and electrochemical activity of SOFC composite cathodes: I. experimental analysis

Morphology and electrochemical activity of SOFC composite cathodes: I. experimental analysis

Synthesis and properties of nanocomposites with mixed ionic-electronic conductivity on the basis of oxide phases with perovskite and fluorite structures

Designing Perovskite Oxides for Solid Oxide Fuel Cells

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