BaCo0.7Fe0.2Nb0.1O3−δ as cathode material for intermediate temperature solid oxide fuel cells

BaCo_0.7Fe_0.2Nb_0.1O_3−δ (BCFN) has been synthesized and characterized as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) using La_0.8Sr_0.2Ga_0.83Mg_0.17O_3−δ (LSGM) electrolyte. X-ray diffraction results show that pure cubic BCFN perovskite phase can be obtained at 950 °C through solid state reactions of BaCO₃, Co₃O₄, Fe₂O₃ and Nb₂O₅. The electrical conductivity of BCFN increases with the increase in oxygen partial pressure, indicating that BCFN is a p-type semiconductor. The polarization resistance of the BCFN cathode with LSGM electrolyte is only 0.06 Ω cm² at 750 °C in air under open-circuit conditions. The overpotential at a current density of 1 A cm⁻² in oxygen was only about 0.04 V at 750 °C. Peak power densities of 550, 770 and 980 mW cm⁻² have been achieved on LSGM-electrolyte supported single cells with the configuration of Ni-Gd_0.1Ce_0.9O_1.95|La_0.4Ce_0.6O₂|LSGM|BCFN at 700, 750 and 800 °C, respectively. These results indicate that BCFN is a very promising cathode candidate for IT-SOFCs with LSGM electrolyte.     

Neodymium-deficient nickelate oxide Nd1.95NiO4+δ as cathode material for anode-supported intermediate temperature solid oxide fuel cells

The neodymium-deficient nickelate Nd_1.95NiO_4+δ, mixed conducting K₂NiF₄-type oxide, was evaluated as cathode for solid oxide fuel cells. The electrochemical properties were investigated on planar Ni–YSZ anode-supported SOFC based on co-tape casted and co-fired HTceramix^® cells. Using a layer of strontium doped lanthanum cobaltite as current collector, a current density of 1.31 A cm⁻² (at 0.70 V) was obtained at 800 °C using hydrogen fuel with small single cells, after optimizing the cathode sintering temperature. Impedance spectroscopy measurements were performed; the different resistive contributions and the values of the corresponding equivalent capacities are discussed.     

Nanoscaled La0.6Sr0.4CoO3−δ as intermediate temperature solid oxide fuel cell cathode: Microstructure and electrochemical performance

Lowering the operation temperature of solid oxide fuel cells to the range of 400-600 °C has generated new concepts for materials choice, interfacial design and electrode microstructures. In this study nanometer scaled and nanoporous La_0.6Sr_0.4CoO_3−δ (LSC) was derived from metal-organic precursors as thin film cathodes of about 200 nm thickness with mean grain sizes ranging from 17 to 90 nm and porosities of up to 45%. These microstructures resulted from different processing parameters such as heating rate, calcination temperature and post calcination annealing, and made it possible to study the influence of the electrode microstructure on the electrochemical performance. Microstructural characteristics were analyzed by scanning and transmission electron microscopy and the performance was evaluated in terms of area specific polarization resistance by means of electrochemical impedance spectroscopy in a temperature range of 400-600 °C. Polarization resistances as low as 0.023 Ω cm² were measured at 600 °C, facilitated by a substantial increase of the inner surface area of the nanoscaled microstructure, resulting from low temperature processing at ≤800 °C, and by enhanced catalytic properties determined for nanoscaled La_0.6Sr_0.4CoO_3−δ prepared by metal organic deposition.     

Electrochemical evaluation of La2NiO4+δ as a cathode material for intermediate temperature solid oxide fuel cells

La₂NiO_4+δ powders were synthesized using a polyaminocarboxylate complex precursor method. La₂NiO_4+δ electrodes were prepared on Ce_0.8Sm_0.2O_1.9 (SDC) substrates using a screen-printing technique. The microstructure feature and electrocatalytic activity of the electrodes were investigated with respect to the calcination temperature of the starting powders and sintering temperature of the electrodes. The effects of microstructure features on the electrochemical properties of La₂NiO_4+δ electrodes have been inspected. Moreover, the electrochemical performance of the La₂NiO_4+δ cathode has been evaluated based on a Ni-SDC anode supported single cell. The single cell showed a modified electrochemical performance compared with the literature results, attaining a maximum power density of 295 mW cm⁻² at 800 °C. For the single cell, applying an Au layer onto the La₂NiO_4+δ cathode led to an evident reduction of ohmic resistance and a substantial enhancement of the maximum power density to 464 mW cm⁻².     

Double-perovskites YBaCo2−xFexO5+δ cathodes for intermediate-temperature solid oxide fuel cells

Double-perovskites YBaCo_2−xFe_xO_5+δ (YBCF, x = 0.0, 0.2, 0.4 and 0.6) are synthesized with a solid-state reaction and are assessed as potential cathode materials for utilization in intermediate-temperature solid oxide fuel cells (IT-SOFCs) on the La_0.9Sr_0.1Ga_0.8Mg_0.115Co_0.085O_2.85 (LSGMC) electrolyte. The YBCF materials exhibit chemical compatibility with the LSGMC electrolyte up to a temperature of 950 °C. The conductivity of the YBCF samples decreases with increasing Fe content, and the maximum conductivity of YBCF is 315 S cm⁻¹ at 325 °C for the x = 0.0 sample. A semiconductor-metal transition is observed at about 300-400 °C. The thermal expansion coefficient of the YBCF samples increases from 16.3 to 18.0 × 10⁻⁶ K⁻¹ in air at temperatures between 30 and 900 °C with increase in Fe content. The area-specific resistances of YBCF cathodes at x = 0.0, 0.2 and 0.4 on the LSGMC electrolyte are 0.11, 0.13 and 0.15 Ω cm² at a temperature of 700 °C, respectively. The maximum power densities of the single cells fabricated with the LSGMC electrolyte, Ce_0.8Sm_0.2O_1.9 (SDC) interlayer, NiO/SDC anode and YBCF cathodes at x = 0.0, 0.2 and 0.4 reach 873, 768 and 706 mW cm⁻², respectively. This study suggests that the double-perovskites YBCF (0 ≤ x ≤ 0.4) can be potential candidates for utilization as IT-SOFC cathodes.     

Enhanced electrochemical performance of solution impregnated La0.8Sr0.2Co0.8Ni0.2O3−δ cathode for intermediate temperature solid oxide fuel cells

Solution impregnated La_0.8Sr_0.2Co_0.8Ni_0.2O₃ + Gd-doped CeO₂ (LSCN + GDC) cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC) are prepared and their electrochemical properties are evaluated and compared with the conventional LSCN cathodes. The results indicate that the cathode performance can be enhanced by the presence of the nanosized microstructure produced with the solution impregnation method. It is determined that the amount of LSCN loading in the LSCN + GDC composite cathode needs to be higher than 35 wt% in order to achieve a performance superior to that of the conventional LSCN cathode. The optimum amount of LSCN loading is in the range of 45-55 wt% with an activation energy near 1.32 eV for oxygen reduction. At temperatures between 600 and 750 °C, the polarization resistance of the 55 wt% LSCN loaded LSCN + GDC cathode is in the range of 1.07 and 0.08 Ω cm², which is only about one half of that for the conventional cathode.     

LaCo0.6Ni0.4O3−δ as cathode contact material for intermediate temperature solid oxide fuel cells

LaCo_0.6Ni_0.4O_3−δ (LCN64) was prepared through the polymeric steric entrapment precursor route with Polyvinyl alcohol (PVA) as the entrapment agent and was evaluated as a contact material between the metallic interconnect and the cathode in planar intermediate temperature solid oxide fuel cell stacks (IT-SOFC). The ratio of PVA to metal nitrates and the calcination temperature of the precursor were optimized for the process. The electrical conductivity and thermal expansion coefficient (TEC) of the synthesized LCN64 and its chemical compatibility with SUS 430 were also characterized. The results indicate that 1:4 is a proper ratio of PVA to metal nitrates for process control and safety management; and calcination of the precursor at temperatures above 650 °C leads to formation of single perovskite phase LCN64. The conductivity of fully sintered LCN64 is above 1150 S cm⁻¹ in the temperature range between 100 °C and 800 °C, which is higher than those of conventional contact materials La_1−xSr_xMnO₃ (LSM) and LaNi_yFe_1−yO₃ (LNF). The average TEC is 17.22 × 10⁻⁶ K⁻¹ at temperatures below 900 °C, which is higher than those of the metallic interconnect and cell components. Mn and Cr elements contained in SUS 430 migrated into the porous LCN64 layer at 800 °C without chemically forming resistive phases.     

Enhanced electrochemical performance of the solid oxide fuel cell cathode using Ca3Co4O9+δ

This paper reports on the electrochemical performance of an SOFC cathode for potential use in intermediate-temperature solid oxide fuel cells (IT-SOFCs) using the oxygen non-stoichiometric misfit-layered cobaltite Ca₃Co₄O_9+δ or composites of Ca₃Co₄O_9+δ with Ce_0.9Gd_0.1O_1.95 (CGO/Ca₃Co₄O_9+δ). Electrochemical impedance spectroscopy revealed that symmetric cells with an electrode of pure Ca₃Co₄O_9+δ exhibit a cathode polarization resistance (R_p) of 12.4 Ω cm², at 600 °C in air. Strikingly, R_p of the composite CGO/Ca₃Co₄O_9+δ with 50 vol.% CGO was reduced by a factor of 19 (i.e. R_p = 0.64 Ω cm²), the lowest value reported so far for the Ca₃Co₄O₉ family of compounds. These findings together with the reported thermal expansion coefficient, good compatibility with CGO and chemical durability of this material suggest that it is a promising candidate cathode for IT-SOFCs.     

Layered LnBa1−xSrxCoCuO5+δ (Ln = Nd and Gd) perovskite cathodes for intermediate temperature solid oxide fuel cells

The effects of Sr substitution on the crystal chemistry, phase stability, and electrochemical performance as cathodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs) of the layered LnBa_1−xSr_xCoCuO_5+δ (Ln = Nd and Gd) perovskites have been investigated. The LnBa_1−xSr_xCoCuO_5+δ oxides crystallize in tetragonal P4/mmm symmetry for 0 ≤ x ≤ 0.75. The x = 0.75 samples show a significant improvement in electrochemical performance compared to the x = 0 samples for both Ln = Nd and Gd. In an electrolyte (La_0.8Sr_0.2Ga_0.8Mg_0.2O_2.8)-supported single cell configuration (thickness = 0.50 mm), the Ln = Gd series shows an improved maximum power density from 468 mW cm⁻² for the Sr-free (x = 0) sample to 530 mW cm⁻² for the x = 0.75 sample. In the Ln = Nd system, the x = 0.75 sample shows a maximum power density of 562 mW cm⁻². The Sr substitution was found to have negligible effect on the thermal expansion coefficients (TEC) between the x = 0 and x = 0.75 samples in both series.     

Novel SrCo1−yNbyO3−δ cathodes for intermediate-temperature solid oxide fuel cells

Perovskite oxides SrCo_1−yNb_yO_3−δ (SCNy, y = 0.00-0.20) are investigated as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) on La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM) electrolyte. Compared to the undoped SrCoO_3−δ, the Nb doping significantly improves the thermal stability and enhances the electrical conductivity of the SCNy oxides. The cubic phase of the SCNy oxides with high thermal stability can be totally obtained when the Nb doping content y ≥ 0.10. Among the investigated compositions, the SrCo_0.9Nb_0.1O_3−δ oxide exhibits the highest electrical conductivity of 461-145 S cm⁻¹ over the temperature range of 300-800 °C in air. The SCNy cathode has a good chemical compatibility with the LSGM electrolyte for temperatures up to 1050 °C for 5 h. The area specific resistances of SCNy with y = 0.10, 0.15 and 0.20 cathodes on LSGM electrolyte are 0.083, 0.099 and 0.110 Ω cm² at 700 °C, respectively. At y = 0.10, 0.15 and 0.20, the maximum power densities of a single-cell with SCNy cathodes on 300-μm thick LSGM electrolyte achieve 675, 642 and 625 mW cm⁻² at 800 °C, respectively. These results indicate that SCNy perovskite oxides with cubic phase are potential cathode materials for application in IT-SOFCs.     

Synthesis, characterization and evaluation of PrBaCo2−xFexO5+δ as cathodes for intermediate-temperature solid oxide fuel cells

Iron doped layered structured perovskites, PrBaCo_2−xFe_xO_5+δ (x = 0, 0.5, 1.0, 1.5 and 2.0), are evaluated as cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The effects of dopant content are investigated on their structural and electrochemical properties including crystalline structure, oxygen nonstoichiometry, stability in presence of CO₂, compatibility with electrolytes, thermal expansion coefficient, electrical conductivity, and cathodic interfacial polarization resistance. The lattice parameter and oxygen nonstoichiometry content, δ, at room temperature increase, whereas the conductivity, thermal expansion coefficient, and cathodic performance decrease with increasing iron content, x. PrBaCo_2−xFe_xO_5+δ exhibit excellent stability at 700 °C in atmosphere consisting of 3% CO₂ and 97% air, show good chemical compatibility with doped ceria electrolytes at 1000 °C, but react readily with yttria-stabilized zirconia at 700 °C. Even with a Co-free PrBaFe₂O_5+δ as the electrode, a symmetrical cell demonstrates area specific resistance of 0.18 Ω cm² at 700 °C with samaria-doped ceria electrolyte. The resistance is lower than those for typical Co-free electrodes reported in the literatures, suggesting that PrBaCo_2−xFe_xO_5+δ are potential promising cathode materials for IT-SOFCs.     

High-performance PrBaCo2O5+δ-Ce0.8Sm0.2O1.9 composite cathodes for intermediate temperature solid oxide fuel cell

PrBaCo₂O_5+δ-Ce_0.8Sm_0.2O_1.9 (PBCO-SDC) composite material are prepared and characterized as cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction result proves that there are no obvious reaction between the PBCO and SDC after calcination at 1100 °C for 3 h. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures shows that the addition of SDC to PBCO improved remarkably the electrochemical performance of a PBCO cathode, and that a PBCO-30SDC cathode exhibits the best electrochemical performance in the PBCO-xSDC system. The total interfacial resistances R_p is the smallest when the content of SDC is 30 wt%, where the value is 0.035 Ω cm² at 750 °C, 0.072 Ω cm² at 700 °C, and 0.148 Ω cm² at 650 °C, much lower than the corresponding interfacial resistance for pure PBCO. The maximum power density of an anode-supported single cell with PBCO-30SDC cathode, Ni-SDC anode, and dense thin SDC/LSGM (La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ)/SDC tri-layer electrolyte are 364, 521 and 741 mW cm⁻² at 700, 750 and 800 °C, respectively.     

Thermal, electrical and electrochemical characteristics of Ba1−xSrxCo0.8Fe0.2O3−δ cathode material for intermediate temperature solid oxide fuel cells

Ba_1−xSr_xCo_0.8Fe_0.2O_3−δ (x = 0.3-0.9) perovskite oxides have been studied as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). The structural characteristics, temperature dependent weight loss, thermal expansion, electrical conductivity, and electrochemical properties in combination with YSZ electrolyte together with an SDC buffer layer were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), dilatometry, DC four probe conductivity measurement and electrochemical impedance spectroscopy (EIS) techniques respectively. XRD study revealed the lattice parameter and unit cell volume decrease with increase in Sr⁺² content at the A-site. TEC and electrical conductivity were found to increase with increasing Sr⁺² content. Electrical conductivity was found to be dependent on the thermal history of the samples. Polarization resistance of the samples with SDC buffered YSZ electrolyte decreased with increasing Sr⁺² content which was ascribed to the higher conductivity with improved oxygen adsorption/desorption and oxygen ions diffusion processes. The intrinsic oxygen reduction reaction rate also increased with Sr⁺² content at the A-site. The exchange current for intrinsic oxygen reduction reaction at 700 °C was found to be 50.0 mA cm⁻² for Ba_0.3Sr_0.7Co_0.8Fe_0.2O_3−δ; a value which is about 50% higher than that for Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ, a widely studied cathode material. Therefore, the present composition may be a potential cathode material for IT-SOFC application.     

Electrochemical performance of La0.7Sr0.3CuO3−δ–Sm0.2Ce0.8O2−δ functional graded composite cathode for intermediate temperature solid oxide fuel cells

The fabrication and electrochemical properties of graded La_0.7Sr_0.3CuO_3−δ–Sm_0.2Ce_0.8O_2−δ (LSCu–SDC) composite cathodes were investigated in this paper. The phase composition, microstructure and electrochemical properties of the electrodes were characterized using X-ray diffraction (XRD), electron microscopy, electrochemical impedance spectroscopy (EIS) and cathodic polarization examinations. The results showed that the triple-layer graded cathode had super electrochemical performance comparing with the monolayer cathode. The graded LSCu–SDC cathode showed a polarization resistance of 0.094 Ωcm², a value much lower than the monolayer LSCu cathode of 0.234 Ωcm² at 800 °C in air. The current density of the graded cathode was 0.341 A cm⁻², more than double higher than monolayer LSCu of 0.146 A cm⁻² at an overpotential of 30 mV. The improved electrochemical performance could be attributed to the improved physical and chemical compatibility of the cathode layers in graded compositions with SDC electrolyte as well as the enlargement of triple-phase boundary for oxygen reduction.     

Nd1.8Sr0.2NiO4−δ:Ce0.9Gd0.1O2−δ composite cathode for intermediate temperature solid oxide fuel cells

The (100 − x)Nd_1.8Sr_0.2NiO_4−δ:(x)Ce_0.9Gd_0.1O_2−δ (x = 00, 10, 20, 30, 40 and 50 vol%) composites are obtained by ball milling requisite mixture at 200 rotations per minute for 2 h under acetone followed by sintering at 1000 °C for 4 h. The increase in concentration of Ce_0.9Gd_0.1O_2−δ in composite reduces the crystallite size of host Nd_1.8Sr_0.2NiO_4−δ from 378 ± 0.7 to 210 ± 0.8 nm. The dc (electronic) conductivity of composite decreases moderately with an increase in Ce_0.9Gd_0.1O_2−δ content in composite up to 30 vol%, and it decreases abruptly, thereafter at x > 30. A minimum polarization resistance value of 0.24 Ω cm² (at 700 °C) is obtained for a (70)Nd_1.8Sr_0.2NiO_4−δ:(30)Ce_0.9Gd_0.1O_2−δ composite cathode, and this value is attributed to the optimal dispersion of Ce_0.9Gd_0.1O_2−δ into Nd_1.8Sr_0.2CuO_4−δ matrix. The oxygen partial pressure dependent polarization resistance study suggests that the charge transfer and the non-charge transfer oxygen adsorption–desorption along with diffusion are the major rate limiting steps of overall oxygen reduction reaction process.     

Evaluation of layered perovskites YBa1−xSrxCo2O5+δ as cathodes for intermediate-temperature solid oxide fuel cells

This study is focused on the structural characteristics, oxygen nonstoichiometry, electrical conductivity, electrochemical performance and oxygen reduction mechanism of YBa_1−xSr_xCo₂O_5+δ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5). The high oxygen nonstoichiometry, δ = 0.18–0.43 at 700 °C, indicates the large oxygen vacancy concentrations in oxides. The electrical conductivity is improved due to the greater amount of electronic holes originated from the increased interstitial oxygen, and the conductivities of all samples are above 100 S cm⁻¹ at 400–700 °C in air. The results demonstrate the promising performance of YBa_1−xSr_xCo₂O_5+δ cathodes at intermediate temperatures, as evidenced by low area-specific resistances (ASRs) e.g. 0.21–0.59 Ω cm² at 700 °C. The lowest ASR, 0.44 Ω cm², and the cathodic overpotential, −40 mV at a current density of −136 mA cm⁻², are obtained in YBaCo₂O_5+δ cathode at 650 °C. The dependence of polarization resistance on oxygen partial pressure suggests that the charge transfer process is the rate-limiting step for oxygen reduction reaction in YBaCo₂O_5+δ cathode.     

Chemical compatibility, thermal expansion matches and electrochemical performance of SrCo0.8Fe0.2O3−δ-La0.45Ce0.55O2−δ composite cathodes for intermediate-temperature solid oxide fuel cells

The chemical compatibility, thermal expansion and electrochemical property measurements of the SrCo_0.8Fe_0.2O_3−δ (SCF)-La_0.45Ce_0.55O_2−δ (LDC) composite cathodes for solid oxide fuel cells (SOFCs) were investigated by X-ray diffraction (XRD), thermal expansion coefficients (TECs) and cathodic polarization measurements together with electrochemical impedance spectroscopy (EIS). The results indicated that LDC had good chemical compatibility with SCF and La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM), and the addition of LDC to SCF markedly reduced the polarization resistance. When the content of LDC reached 50 wt%, the SCF50 cathode showed the best electrochemical performance, with a cathodic overpotential of 0.1 V at the current density of 1102.0 mA cm⁻², together with a polarization resistance of 0.149 Ω cm² at 800 °C. The improved electrochemical performance was attributed to the expansion of the electrochemical reaction region into the electrode, and offering an easier path for the oxygen ion transport. Furthermore, the SCF-LDC composite cathodes match better with the LSGM electrolyte.     

Novel BaCe0.7In0.2Yb0.1O3−δ proton conductor as electrolyte for intermediate temperature solid oxide fuel cells

Novel proton conductor BaCe_0.7In_0.2Yb_0.1O_3−δ (BCIYb) has been successfully synthesized by a modified Pechini method and characterized as electrolyte for intermediate temperature solid oxide fuel cells. Acceptable tolerance to wet CO₂ environment was found during chemical stability tests. No interaction between the BCIYb electrolyte and La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) cathode was observed during the cathode fabrication process. Further, no detectable impurity phase was found when the BCIYb-LSCF mixed powders were calcined at 700 °C for 50 h. BCIYb dense samples sintered at 1450 °C for 5 h showed acceptable conductivities of 7.2 × 10⁻³, 8 × 10⁻³, 4.5 × 10⁻³ and 3.1 × 10⁻³ S cm⁻¹ at 800 °C in dry air, wet air, wet H₂ and wet N₂, respectively. The maximum cell power outputs of single cells with the configuration of Ni-BaZr_0.1Ce_0.7Y_0.2O_3−δ (BZCY)|BCIYb|BZCY-LSCF were 0.15, 0.218 and 0.28 W cm⁻² at 600, 650 and 700 °C, respectively. No cell degradation was observed for cells operated at a constant voltage of 0.7 V in the 25 h short-term durability test.     

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.     

In situ drop-coated BaZr0.1Ce0.7Y0.2O3−δ electrolyte-based proton-conductor solid oxide fuel cells with a novel layered PrBaCuFeO5+δ cathode

In order to develop a simple and cost-effective route to fabricate proton-conductor intermediate-temperature SOFCs, a dense BaZr_0.1Ce_0.7Y_0.2O_3−δ (BZCY) electrolyte was fabricated on a porous anode by in situ drop-coating. The PrBaCuFeO_5+δ (PBCF) composite oxide with layered perovskite structure was synthesized by auto ignition process and examined as a novel cathode for proton-conductor IT-SOFCs. The single cell, consisting of PBCF/BZCY/NiO-BZCY structure, was assembled and tested from 600 to 700 °C with humidified hydrogen (∼3% H₂O) as the fuel and the static air as the oxidant. An open-circuit potential of 1.01 V and a maximum power density of 445 mW cm⁻² at 700 °C were obtained for the single cell. A relatively low interfacial polarization resistance of 0.15 Ω cm² at 700 °C indicated that the PBCF is a promising cathode for proton-conductor IT-SOFCs.