Synthesis and electrochemical performance of La0.6Ca0.4Fe1−xNixO3 (x = 0.1, 0.2, 0.3) material for solid oxide fuel cell cathode

Polycrystalline samples of La_0.6Ca_0.4Fe_1−xNi_xO₃ (x = 0.1, 0.2, 0.3) (LCFN) are prepared by liquid mix method. The structure of the polycrystalline powders is analyzed with X-ray powder diffraction data. The XRD patterns are indexed as the orthoferrite similar to that of LaFeO₃ having a single phase with orthorhombic perovskite structure (Pnma). The morphological characterization is performed by scanning electron microscopy (SEM) obtaining a mean particle size less than 300 nm.Polarization resistance is studied using two different electrolytes: Y-stabilized zirconia (YSZ) and Sm-doped ceria (SDC). Electrochemical impedance spectroscopy (EIS) measurements of LCFN/YSZ/LCFN and LCFN/SDC/LCFN test cells are carried out. These electrochemical experiments are performed at equilibrium from 850 °C to room temperature, under both zero dc current intensity and air. The best value of area specific resistance (ASR) obtained is 0.88 Ω cm², corresponding to the La_0.6Ca_0.4Fe_0.9Ni_0.1O₃ material using SDC as electrolyte. The dc four-probe measurement indicates that La_0.6Ca_0.4Fe_0.9Ni_0.1O₃ exhibits fairly high electrical conductivity, over 300 S cm⁻¹ at T > 500 °C.     

Evaluation of Sr substituted Nd2CuO4 as a potential cathode material for intermediate-temperature solid oxide fuel cells

The Nd_1.7Sr_0.3CuO₄ (NSCu) material with perovsikite-related structure was synthesized and evaluated as a new cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, thermal expansion, electrical conductivity and electrochemical performance of NSCu have been investigated by X-ray diffraction, a dilatometer, DC four-probe method, AC impedance and cyclic voltammetry (CV) techniques. The polarization resistances of NSCu cathode on Sm-doped ceria (SDC) electrolyte in air were 0.07 Ω cm², 0.24 Ω cm² and 1.60 Ω cm² at 800 °C, 700 °C and 600 °C, respectively. The results demonstrated that both impedance and CV methods are consistent with high exchange current density i₀ (390.7 mA/cm² and 76.1 mA/cm² at 800 °C and 700 °C.), making NSCu a promising cathode material for the IT-SOFCs based on doped ceria electrolytes.     

Combustion synthesis and properties of highly phase-pure perovskite electrolyte Co-doped La0.9Sr0.1Ga0.8Mg0.2O2.85 for IT-SOFCs

The highly phase-pure perovskite electrolyte, La_0.9Sr_0.1Ga_0.8Mg_0.115Co_0.085O_2.85 (LSGMCO), was prepared by means of glycine–nitrate process (GNP) for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The perovskite phase evolution, sintering, electrical conductivity and electrochemical performance of LSGMCO were investigated. The results show that the highly phase-pure perovskite electrolyte LSGMCO can be obtained after calcining at 1150 °C. The sample sintered at 1450 °C for 20 h in air exhibited a better sinterability, and the relative density of LSGMCO was higher than 95%. The stoichiometric indexes of the elements in the sintered sample LSGMCO determined experimentally by EDS were in good agreement with the nominal composition. The electrical conductivities of the sample were 0.094 and 0.124 S· cm⁻¹ at 800 °C and 850 °C in air, respectively. The ionic conduction of the sample was dominant at high temperature with the higher activation energies. While at lower temperature the electron hole conduction was predominated with the lower activation energies. The maximum power densities of the single cell fabricated with LSGMCO electrolyte with Ce_0.8Sm_0.2O_1.9 (SDC) interlayer, SmBaCo₂O_5+x cathode and NiO/SDC anode achieved 643 and 802 mW cm⁻² at 800 °C and 850 °C, respectively.     

Electrochemical performance of (Ba0.5Sr0.5)0.9Sm0.1Co0.8Fe0.2O3−δ as an intermediate temperature solid oxide fuel cell cathode

This study presents the electrochemical performance of (Ba_0.5Sr_0.5)_0.9Sm_0.1Co_0.8Fe_0.2O_3−δ (BSSCF) as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFC). AC-impedance analyses were carried on an electrolyte supported BSSCF/Sm_0.2Ce_0.8O_1.9 (SDC)/Ag half-cell and a Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF)/SDC/Ag half-cell. In contrast to the BSCF cathode half-cell, the total resistance of the BSSCF cathode half-cell was lower, e.g., at 550 °C; the values for the BSSCF and BSCF were 1.54 and 2.33 Ω cm², respectively. The cell performance measurements were conducted on a Ni-SDC anode supported single cell using a SDC thin film as electrolyte, and BSSCF layer as cathode. The maximum power densities were 681 mW cm⁻² at 600 °C and 820 mW cm⁻² at 650 °C.     

A cobalt-free Sm0.5Sr0.5Fe0.8Cu0.2O3−δ-Ce0.8Sm0.2O2−δ composite cathode for proton-conducting solid oxide fuel cells

A cobalt-free composite Sm_0.5Sr_0.5Fe_0.8Cu_0.2O_3−δ-Ce_0.8Sm_0.2O_2−δ (SSFCu-SDC) is investigated as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs) in intermediate temperature range, with BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ (BZCYYb) as the electrolyte. The XRD results show that SSFCu is chemically compatible with SDC at temperatures up to 1100 °C. The quad-layer single cells of NiO-BZCYYb/NiO-BZCYYb/BZCYYb/SSFCu-SDC are operated from 500 to 700 °C with humidified hydrogen (∼3% H₂O) as fuel and the static air as oxidant. It shows an excellent power density of 505 mW cm⁻² at 700 °C. Moreover, a low electrode polarization resistance of 0.138 Ω cm² is achieved at 700 °C. Preliminary results demonstrate that the cobalt-free SSFCu-SDC composite is a promising cathode material for H-SOFCs.     

Ba0.5Sr0.5Co0.8Fe0.2O3 − δ + LaCoO3 composite cathode for Sm0.2Ce0.8O1.9-electrolyte based intermediate-temperature solid-oxide fuel cells

A novel Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3 − δ + LaCoO₃ (BSCF + LC) composite oxide was investigated for the potential application as a cathode for intermediate-temperature solid-oxide fuel cells based on a Sm_0.2Ce_0.8O_1.9 (SDC) electrolyte. The LC oxide was added to BSCF cathode in order to improve its electrical conductivity. X-ray diffraction examination demonstrated that the solid-state reaction between LC and BSCF phases occurred at temperatures above 950 °C and formed the final product with the composition: La_0.316Ba_0.342Sr_0.342Co_0.863Fe_0.137O_3 − δ at 1100 °C. The inter-diffusion between BSCF and LC was identified by the environmental scanning electron microscopy and energy dispersive X-ray examination. The electrical conductivity of the BSCF + LC composite oxide increased with increasing calcination temperature, and reached a maximum value of ∼300 S cm⁻¹ at a calcination temperature of 1050 °C, while the electrical conductivity of the pure BSCF was only ∼40 S cm⁻¹. The improved conductivity resulted in attractive cathode performance. An area-specific resistance as low as 0.21 Ω cm² was achieved at 600 °C for the BSCF (70 vol.%) + LC (30 vol.%) composite cathode calcined at 950 °C for 5 h. Peak power densities as high as ∼700 mW cm⁻² at 650 °C and ∼525 mW cm⁻² at 600 °C were reached for the thin-film fuel cells with the optimized cathode composition and calcination temperatures.     

Solid oxide fuel cells with Sm0.2Ce0.8O2−δ electrolyte film deposited by novel aerosol deposition method

In this study, dense electrolyte ceramic Sm_0.2Ce_0.8O_2−δ (SDC) thin films are successfully deposited on NiO-SDC anode substrate by aerosol deposition (AD) with oxygen as the carrier gas at the substrate temperature ranging from room temperature to 300 °C. To remove the effect of humidity on the starting powders, this study found that, in depositing SDC films, having the starting powders preheat-treated at 200 °C helped generate a smooth and dense layer, though a lower deposition rate was achieved. At a deposition time of 22 min, SDC films with a uniform thickness of 1.5 μm and grain sizes of ≈67 nm are obtained. SOFC single cells are then built by screen printing a LSCF cathode on the anode-supported substrates with SDC electrolyte. The cross-sectional SEM micrographs exhibit highly dense, granular, and crack-free microstructures. The open circuit voltages (OCV) of the single cells decrease with the rise in temperature, dropping from 0.81 V at 500 °C to 0.59 V at 700 °C. Maximum power densities (MPD) decline with decreasing operating temperature from 0.34 to 0.01 W cm⁻² due to the increase of the R₀ and R_P of the single cells. The electrochemical results testify to the fine quality of SDC films as well as illustrate the electrolyte thickness effect and the effect of mixed ionic and electronic conduction of the SDC electrolyte in the reducing atmosphere.     

Performances of LnBaCo2O5+x-Ce0.8Sm0.2O1.9 composite cathodes for intermediate-temperature solid oxide fuel cells

Double-perovskite oxides, LnBaCo₂O_5+x (LnBCO) (Ln = Pr, Nd, Sm, and Gd), are prepared using a solid-state reaction as cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The performances of LnBCO-Ce_0.8Sm_0.2O_1.9 (SDC) composite cathodes were investigated for IT-SOFCs on La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM) electrolyte. The thermal expansion coefficient can be effectively reduced in the case of the composite cathodes. No chemical reactions between LnBCO cathodes and SDC electrolyte, and LnBCO and LSGM are found. The electrochemical performances of LnBCO cathodes and LnBCO-SDC composite cathodes decrease with decreasing Ln³⁺ ionic radii, which is closely related to the decrease of the electrical conductivity and fast oxygen diffusion property. The area specific resistances of the LnBCO cathodes and LnBCO-SDC composite cathodes on LSGM electrolyte are all lower than 0.13 Ω cm² and 0.15 Ω cm² at 700 °C, respectively. The maximum power densities of single-cell consisted of LnBCO-SDC composite cathodes, LSGM electrolyte, and Ni-SDC anode achieve 758-608 mW cm⁻² at 800 °C with the change from Ln = Pr to Gd, respectively. These results indicate that LnBCO-SDC composite oxides are candidates as a promising cathode material for IT-SOFCs.     

Fabrication and evaluation of Ag-impregnated BaCe0.8Sm0.2O2.9 composite cathodes for proton conducting solid oxide fuel cells

Ag-BaCe_0.8Sm_0.2O_2.9 (BCS) composite cathodes are fabricated by an ion impregnation technique in this work, and the effect of fabrication details on their electro-performance is studied. The firing temperature of impregnated Ag has little effect on Ag loading but has a great impact on the polarization resistances. When fired at 400 °C, the minimum polarization resistance for symmetric cells reaches 0.11 Ω cm² measured at 600 °C with an Ag loading of 0.40 mg cm⁻². When fired at 600 °C, the minimum polarization resistance is 29.73 Ω cm² at 600 °C with 0.24 mg cm⁻² Ag-impregnated cathodes due to severe aggregation. The performance of Ag-impregnated cathodes is also compared with that of a Sm_0.5Sr_0.5CoO_3−δ (SSC) impregnated cathode. With the same volume ratio of 57%, the polarization resistance of an Ag-impregnated cathode is only about half of that for a SSC-impregnated cathode. Resistance simulation suggests that the reduction of low frequency resistances is the main reason for the decrease in polarization resistances in Ag-impregnated cathodes, which is consistent with its high oxygen diffusion coefficient. With a 57 vol.% Ag-impregnated cathode fired at 400 °C, the maximum power density of single cells is 283 mW cm⁻² at 600 °C, about 16% larger than that for a 57 vol.% SSC-impregnated cathode.     

Electrochemical oxidation of catalytic grown carbon fiber in a direct carbon fuel cell using Ce0.8Sm0.2O1.9-carbonate electrolyte

The electrochemical oxidation of catalytic grown carbon fiber has been examined in a direct carbon fuel cell (DCFC). The single cell contains a composite electrolyte layer made of a samarium doped ceria (SDC) and a eutectic carbonate phase. The cathode is a mixture of lithiated NiO and the composite electrolyte, while the anode is composed of NiO and SDC powder. Catalytic carbon fiber and the eutectic carbonate is premixed and used as the feed of the anode fuel. The effects of the cell pellet configuration, cathode gas composition and the operation temperature on the DCFC performance have been examined in this work. At 700 °C, the maximum power output achieves 112 mW cm⁻² with a current density of 249 mA cm⁻². The anode off-gas is analyzed with a gas chromatograph, and the Boudouard reaction is found suppressed by the electrical field in the fuel cell operation.     

New insights in the polarization resistance of anode-supported solid oxide fuel cells with La0.6Sr0.4Co0.2Fe0.8O3 cathodes

In this study, the polarization resistance of anode-supported solid oxide fuel cells (SOFC) with La_0.6Sr_0.4Co_0.2Fe_0.8O₃ (LSCF) cathodes was investigated by I-V sweep and electrochemical impedance spectroscopy under a series of operating voltages and cathode environments (i.e. stagnant air, flowing air, and flowing oxygen) at temperatures from 550 °C to 750 °C. In flowing oxygen, the polarization resistance of the fuel cell decreased considerably with the applied current density. A linear relationship was observed between the ohmic-free over-potential and the logarithm of the current density of the fuel cell at all the measuring temperatures. In stagnant or flowing air, an arc related to the molecular oxygen diffusion through the majority species (molecular nitrogen) present in the pores of the cathode was identified at high temperatures and high current densities. The magnitude of this arc increased linearly with the applied current density due to the decreased oxygen partial pressure at the interface of the cathode and the electrolyte. It is found that the performance of the fuel cell in air is mainly determined by the oxygen diffusion process. Elimination of this process by flowing pure oxygen to the cathode improved the cell performance significantly. At 750 °C, for a fuel cell with a laser-deposited Sm_0.2Ce_0.8O_1.9 (SDC) interlayer, an extraordinarily high power density of 2.6 W cm⁻² at 0.7 V was achieved in flowing oxygen, as a result of reduced ohmic and polarization resistance of the fuel cell, which were 0.06 Ω cm² and 0.03 Ω cm², respectively. The results indicate that microstructural optimization of the LSCF cathode or adoption of a new cell design which can mitigate the oxygen diffusion limitation in the cathode might enhance cell performance significantly.     

Electrochemical performance of a solid oxide fuel cell based on Ce0.8Sm0.2O2−δ electrolyte synthesized by a polymer assisted combustion method

A polyvinyl alcohol assisted combustion synthesis method was used to prepare Ce_0.8Sm_0.2O_2−δ (SDC) powders for an intermediate temperature solid oxide fuel cell (IT-SOFC). The XRD results showed that this combustion synthesis route could yield phase-pure SDC powders at a relatively low calcination temperature. A thin SDC electrolyte film with thickness control was produced by a dry pressing method at a lower sintering temperature of 1250 °C. With Sm_0.5Sr_0.5Co₃-SDC as the composite cathode, a single cell based on this thin SDC electrolyte was tested from 550 to 650 °C. The maximum power density of 936 mW cm⁻² was achieved at 650 °C using humidified hydrogen as the fuel and stationary air as the oxidant.     

LaNi0.6Fe0.4O3-Ce0.8Sm0.2O1.9-Ag composite cathode for intermediate temperature solid oxide fuel cells

LaNi_0.6Fe_0.4O₃ (LNF), LNF-Sm_0.2Ce_0.8O_1.9 (SDC), and LNF-SDC-Ag cathodes on SDC electrolytes were investigated at intermediate temperatures using AC impedance spectroscopy. Results show that adding 50 wt.% SDC into LNF yields a significant low area specific resistance (ASR) which was found to be 0.92 Ω cm² at 700 °C. Infiltrating 0.3 mg/cm² Ag into LNF-50 wt.% SDC can improve the electronic conductivity and oxygen exchange reaction activity, and thereby remarkably decrease the ASRs. The ASR value of the LNF-SDC-Ag cathode is as low as 0.18 Ω cm² at 700 °C, and 0.46 Ω cm² at 650 °C. The long-term test shows that the LNF-SDC-Ag cathode may be a promising candidate for solid oxide fuel cells operating at temperatures lower than 650 °C.     

Fabrication and characterization of a co-fired La0.6Sr0.4Co0.2Fe0.8O3−δ cathode-supported Ce0.9Gd0.1O1.95 thin-film for IT-SOFCs

A dense membrane of Ce_0.9Gd_0.1O_1.95 on a porous cathode based on a mixed conducting La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ was fabricated via a slurry coating/co-firing process. With the purpose of matching of shrinkage between the support cathode and the supported membrane, nano-Ce_0.9Gd_0.1O_1.95 powder with specific surface area of 30 m² g⁻¹ was synthesized by a newly devised coprecipitation to make the low-temperature sinterable electrolyte, whereas 39 m² g⁻¹ nano-Ce_0.9Gd_0.1O_1.95 prepared from citrate method was added to the cathode to favor the shrinkage for the La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ. Bi-layers consisting of <20 μm dense ceria film on 2 mm thick porous cathode were successfully fabricated at 1200 °C. This was followed by co-firing with NiO–Ce_0.9Gd_0.1O_1.95 at 1100 °C to form a thin, porous, and well-adherent anode. The laboratory-sized cathode-supported cell was shown to operate below 600 °C, and the maximum power density obtained was 35 mW cm⁻² at 550 °C, 60 mW cm⁻² at 600 °C.     

LaNi0.8Co0.2O3 as a cathode catalyst for a direct borohydride fuel cell

A perovskite-type oxide LaNi_0.8Co_0.2O₃ is prepared as a direct borohydride fuel cell (DBFC) cathode catalyst. Its electrochemical properties are studied by cyclic voltammetry. The results demonstrate that LaNi_0.8Co_0.2O₃ exhibits excellent electrochemical activity with respect to the oxygen reduction reaction (ORR) and good tolerance of BH₄⁻ ions. Maximum power densities of 114.5 mW cm⁻² at 30 °C and 151.3 mW cm⁻² at 62 °C are obtained, and good stability (300-h stable performance at 20 mA cm⁻²) is also exhibited, which shows that such perovskite-type oxides as LaNi_0.8Co_0.2O₃ can be excellent catalysts for DBFCs.     

Preparation and characterization of nanocrystalline Ce0.8Sm0.2O1.9 for low temperature solid oxide fuel cells based on composite electrolyte

Nanocrystalline Ce_0.8Sm_0.2O_1.9 (SDC) has been synthesized by a combined EDTA–citrate complexing sol–gel process for low temperature solid oxide fuel cells (SOFCs) based on composite electrolyte. A range of techniques including X-ray diffraction (XRD), and electron microscopy (SEM and TEM) have been employed to characterize the SDC and the composite electrolyte. The influence of pH values and citric acid-to-metal ions ratios (C/M) on lattice constant, crystallite size and conductivity has been investigated. Composite electrolyte consisting of SDC derived from different synthesis conditions and binary carbonates (Li₂CO₃–Na₂CO₃) has been prepared and conduction mechanism is discussed. Water was observed on both anode and cathode side during the fuel cell operation, indicating the composite electrolyte is co-ionic conductor possessing H⁺ and O²⁻ conduction. The variation of composite electrolyte conductivity and fuel cell power output with different synthesis conditions was in accordance with that of the SDC originated from different precursors, demonstrating O²⁻ conduction is predominant in the conduction process. A maximum power density of 817 mW cm⁻² at 600 °C and 605 mW cm⁻² at 500 °C was achieved for fuel cell based on composite electrolyte.     

A comparative study of La0.8Sr0.2MnO3 and La0.8Sr0.2Sc0.1Mn0.9O3 as cathode materials of single-chamber SOFCs operating on a methane-air mixture

As candidates of cathode materials for single-chamber solid oxide fuel cells, La_0.8Sr_0.2MnO₃ (LSM) and La_0.8Sr_0.2Sc_0.1Mn_0.9O₃ (LSSM) were synthesized by a combined EDTA-citrate complexing sol-gel process. The solid precursors of LSM and LSSM were calcined at 1000 and 1150 °C, respectively, to obtain products with similar specific surface area. LSSM was found to have higher activity for methane oxidization than LSM due to LSSM's higher catalytic activity for oxygen reduction. Single cells with these two cathodes initialized by ex situ reduction had similar peak power densities of around 220 mW cm⁻² at 825 °C. The cell using the LSM cathode showed higher open-circuit-voltage (OCV) at corresponding temperatures due to its reduced activity for methane oxidation relative to LSSM. A negligible effect of methane and CO₂ on the cathode performance was observed for both LSM and LSSM via electrochemical impedance spectroscopy analysis. The high phase stability of LSSM under reducing atmosphere allows a more convenient in situ reduction for fuel cell initiation. The resultant cell with LSSM cathode delivered a peak power density of ∼200 mW cm⁻² at 825 °C, comparable to that from ex situ reduction.     

Significant impact of the current collection material and method on the performance of Ba0.5Sr0.5Co0.8Fe0.2O3−δ electrodes in solid oxide fuel cells

The effects of the current collection material and method on the performance of SOFCs with Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) cathodes are investigated. Ag paste and LaCoO₃ (LC) oxide are studied as current collection materials, and five different current collecting techniques are attempted. Cell performances are evaluated using a current-voltage test and electrochemical impedance spectra (EIS) based on two types of anode-supported fuel cells, i.e., NiO + SDC|SDC|BSCF and NiO + YSZ|YSZ|SDC|BSCF. The cell with diluted Ag paste as the current collector exhibits the highest peak power density, nearly 16 times that of a similar cell without current collector. The electrochemical characteristics of the BSCF cathode with different current collectors are further determined by EIS at 600 °C using symmetrical cells. The cell with diluted Ag paste as the current collector displays the lowest ohmic resistance (1.4 Ω cm²) and polarization resistance (0.1 Ω cm²). Meanwhile, the surface conductivities of various current collectors are measured by a four-probe DC conductivity technique. The surface conductivity of diluted Ag paste is 2-3 orders of magnitude higher than that of LC or BSCF. The outstanding surface conductivity of silver may reduce the contact resistance at the current collector/electrode interface and, thus, contributes to better electrode performance.     

Novel layered perovskite oxide PrBaCuCoO5+δ as a potential cathode for intermediate-temperature solid oxide fuel cells

A novel layered perovskite oxide PrBaCuCoO_5+δ (PBCCO) is employed as a potential cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Thermal expansion and electrochemical performance on samarium-doped ceria (SDC) electrolyte are evaluated. The thermal expansion coefficient (TEC) of PrBaCuCoO_5+δ (PBCCO) is close to that of SDC electrolyte and electrical conductivity of PrBaCuCoO_5+δ (PBCCO) reaches the general required value of cathode material. Symmetrical electrochemical cell with the configuration of PrBaCuCoO_5+δ (PBCCO)/SDC/PrBaCuCoO_5+δ (PBCCO) applied for the impedance studies, the area specific resistance of PrBaCuCoO_5+δ (PBCCO) cathode is as low as 0.047 Ω cm² at 700 °C. A maximum power density of 791 mW cm⁻² is obtained at 700 °C for the single cell consisting of PrBaCuCoO_5+δ (PBCCO)/SDC/NiO-SDC. Preliminary results indicate that PrBaCuCoO_5+δ (PBCCO) is especially promising as a cathode for IT-SOFCs.     

Development of electrolyte-supported intermediate-temperature single-chamber solid oxide fuel cells using Ln0.7Sr0.3Fe0.8Co0.2O3−δ (Ln = Pr, La, Gd) cathodes

Iron-cobalt-based perovskite oxides with general formula Ln_0.7Sr_0.3Fe_0.8Co_0.2O_3−δ (where Ln = La, Pr and Gd) have been investigated for their application as intermediate-temperature cathodes in solid oxide fuel cells (SOFCs). Powdered samples of these materials were synthesized by a novel gel combustion process and then characterized by X-ray powder diffraction (XPD) and scanning electron microscopy (SEM). XPD patterns were satisfactorily indexed with an orthorhombic GdFeO₃-type structure and, for all samples, a mean particle size of less than 1 μm was estimated from the SEM data. Experimental single-chamber SOFCs using with these materials as cathodes and NiO-SDC (samaria-doped ceria) and SDC as anode and electrolyte, respectively, were evaluated at 600 °C in a methane/oxygen mixtures. Peak power densities of 65.4, 48.7 and 46.2 mW cm⁻² were obtained for Ag|Ln_0.7Sr_0.3Fe_0.8Co_0.2O_3−δ|SDC|NiO-SDC|Pt cells with Ln = Pr, La and Gd, respectively. The relatively high power density obtained for the Pr compound shows that it could be an interesting material for cathode of single-chamber SOFCs.