Intermediate Temperature Solid Oxide Fuel Cells Research Articles

Preparation and characterization of La1.75Y0.25Mo2-xAlxO9-δ as solid electrolyte for intermediate temperatures SOFC

Yttrium and aluminium co-substitutions on lanthanum molybdate ceramics with the nominal formula La1.75Y0.25Mo2-xAlxO9-?? (LYMA, x = 0, 0.1, 0.2, 0.3 and 0.4) were synthesized by citric acid-nitrate combustion method and used for preparation of solid electrolyte for intermediate-temperature solid oxide fuel cells (ITSOFCs). Phase composition, structure, conductivity and electrical properties of LYMA have been investigated as a function of aluminium content by X-ray diffraction, scanning electron microscopy and electrochemical impedance spectroscopy, respectively. Experimental results showed that the substitution of La and Mo with appropriate amounts of Y and Al can effectively stabilize the ?-form of La2Mo2O9 at room temperature and inhibit its phase transition to ?-form. The LYMA synthesized by combustion method exhibited a better sinterability where relative density of the samples sintered at 950?C for 4 h was higher than 95%TD. The performance of the LYMA electrolyte was found to be related to Al-content. The La1.75Y0.25Mo1.8Al0.2O8.7 exhibited high oxide ion conductivity (?= 42mS/cm at 800?C) and low electrical activation energy (Ea = 1.18 eV). These preliminary results indicate that the LYMA is a promising electrolyte for IT-SOFCs.

Development of oxide composite materials for cathode element of IT-SOFCs

Investigating the properties of composite oxide for intermediate temperature solid oxide fuel cells (IT-SOFCs) has been done as a new cathode material. Using a solid-state reaction method, the metallic oxide material has been employed to create the composite model system. During the sintering process, a model system of Sm0.5Sr0.35Ba0.15FeO3-δ (SSBF15) was constructed. Thermal gravimetric analysis (TG) was played to utilize the oxygen content and weight loss of the model. In the meantime, the structure of the composite was characterized using X-ray diffraction (XRD), and the conductivity properties were tested by thermal conductivity. The structural design was made possible by the findings, which revealed that the composite model structure exhibited the crystalline structure with perovskite phase. Weight losses during the construction of the structure were reflected in the decomposition and evaporation of the composite's constituent parts. After the calcination process up to 950 °C, the model system's formation oxygen content was obtained of 2.94 in 800 °C. The electrical conductivity maximum obtained in 12.2 S·cm-1 at 430 °C. At low temperatures, the conductive behavior was affected by the metallic element, while at higher temperatures, it was influenced by the ionic structure. As a result, mixed ionic and electric conductors (MIEC) were extensively utilized in the process of generating the conductive properties. The SSBF15 composite has a good chance of being used as an alternative cathode material with a perovskite single phase for future IT-SOFCs applications based on the structure and conductivity results. Additional testing and observation are required to determine the resistance's value when incorporated into the electrolyte and its heat expansion properties

Tailoring dual redox pairs strategy on a defective spinel Mg0.4NixMn2.6−xO4+δ cathode for the boosting of SOFCs performance

The oxygen hopping through oxygen defect site plays an extremely important role in cathode catalysts of solid oxide fuel cells (SOFC) application. Herein, a dual Ni2+/Ni3+ and Mn2+/Mn3+/Mn4+ redox pairs strategy is developed to construct a series of defective spinel Mg0.4NixMn2.6−xO4+δ (abbreviated MN(x)MO) to gain insights in terms of oxygen nonstoichiometry. By regulating the stoichiometric proportion of Ni and Mn, it is possible to optimize electronic conductivity and oxygen-vacancy concentration. The optimized MN(1.4)MO provides electrical conductivity as high as 68 S·cm−1 at 800 °C, 2.72 folds that of MN(1.0)MO. Based on oxygen transport performance, the surface exchange coefficient of MN(1.4)MO at 900 °C is 162 folds that of commercial La0.7Sr0.3MnO3-δ (LSM). When a MN(1.4)MO cathode was used, the resulted SOFC exhibited extraordinarily high maximum power density of 0.34 W·cm−2 at 600 °C and 2.02 W·cm−2 at 800 °C. To the best of our knowledge, the performance is the best among the spinel-based cathodes ever reported for SOFC application. Endowed with optimal properties, MN(1.4)MO-based SOFC displays peak power density which is 2.27 and 1.44 folds that of LSM-based SOFC at 600 °C and 800 °C, respectively. A test of 50 h revealed the MN(1.4)MO-based SOFC is remarkably stable at 800 °C, continuously offering 2.02 W·cm−2 at 0.5 V. The excellent performance and stability of MN(1.4)MO-based SOFC suggests that MN(1.4)MO is a promising cathode material for the development of intermediate temperature SOFC technology.

A medium entropy cathode with enhanced chromium resistance for solid oxide fuel cells

Perovskite type SrCo0.9Ta0.1O3-δ (SCT91) cathode exhibits high activity for oxygen reduction reactions, but the instability in Cr-containing atmosphere restricts its application in intermediate temperature solid oxide fuel cells (IT-SOFCs). In this study, a B-site medium-entropy SrCo0.5Fe0.2Ti0.1Ta0.1Nb0.1O3-δ (SCFTTN52111) cathode is proposed and investigated as a potential Cr-tolerance cathode. The electrochemical activity of pristine SCT91 cathode degrades rapidly in the presence of volatile chromium species. In contrast, SCFTTN52111 performs very stable. Chromium vapors prefer to react with segregated SrO species rather than Co3O4 precipitates. Significant secondary phases of SrCrO4 and Co3O4 are detected on SCT91 electrode, while only trace by-products are found on medium-entropy cathode. The better Cr tolerance is closely related to the enhanced structural stability by medium-entropy engineering and reduced surface Sr segregations. This work sheds light on the development of robust cathodes for IT-SOFCs through rational design of configuration entropy.

Tuning Electrochemical Performance by Microstructural Optimization of the Nanocrystalline Functional Oxygen Electrode Layer for Solid Oxide Cells.

Further development of solid oxide fuel cell (SOFC) oxygen electrodes can be achieved through improvements in oxygen electrode design by microstructure miniaturization alongside nanomaterial implementation. In this work, improved electrochemical performance of an La0.6Sr0.4Co0.2Fe0.8O3-d (LSCF) cathode was achieved by the controlled modification of the La0.6Sr0.4CoO3-d (LSC) nanocrystalline interlayer introduced between a porous oxygen electrode and dense electrolyte. The evaluation was carried out for various LSC layer thicknesses, annealing temperatures, oxygen partial pressures, and temperatures as well as subjected to long-term stability tests and evaluated in typical operating conditions in an intermediate temperature SOFC. Electrochemical impedance spectroscopy and a distribution of relaxation times analysis were performed to reveal the rate-limiting electrochemical processes that limit the overall electrode performance. The main processes with an impact on the electrode performance were the adsorption of gaseous oxygen O2, dissociation of O2, and charge transfer-diffusion (O2-). The introduction of a nanoporous and nanocrystalline interlayer with extended electrochemically active surface area accelerates the oxygen surface exchange kinetics and oxygen ion diffusions, reducing polarization resistances. The polarization resistance of the reference LSCF was lowered by one order of magnitude from 0.77 to 0.076 Ω·cm2 at 600 °C by the deposition of a 400 nm LSC interlayer at the interface. The developed electrode tested in the anode-supported fuel cell configuration showed a higher cell performance by 20% compared to the cell with the reference electrode. The maximum power density at 700 °C reaches 675 and 820 mW·cm-2 for the reference cell and the cell with the LSC interlayer, respectively. Aging tests at 700 °C under a high load of 1 A·cm2 were performed.

Performance evaluation of Ca2.9−xBi0.1PrxCo4O9−δ cathode for anode-supported intermediate temperature solid oxide fuel cells

The Ca2.9−xBi0.1PrxCo4O9−δ (CBPxC, x = 0–0.6) oxides were prepared by sol–gel method, as the potential cathode of anode-supported intermediate temperature solid oxide fuel cells (IT-SOFCs). The electrochemical performance test showed that the CBPxC oxide sintered at 700 °C for 10 h could form a single-phase crystal structure, and when the doping ratio of Pr ion was x = 0.4, the CBPxC cathode on the SDC electrolyte sintered at 950 °C for 5 h obtained the minimum interface polarization resistance (about 0.406 Ω·cm2 at 800 °C). Meanwhile, on the basis of the above conditions, we had fabricated Ni0.95Cu0.05Ox-SDC/SDC/CBP0.4C single cell with the optimized CBPxC (x = 0.4) cathode, in which the SDC electrolyte thickness was 55.6 μm. The maximum power densities of the single cell reached 0.705 W/cm2 and 0.570 W/cm2 at 800 °C and 750 °C, the corresponding polarization resistances were 0.051 Ω·cm2 and 0.153 Ω·cm2, respectively. This suggested that CBP0.4C was a very promising cathode material for IT-SOFCs.

Nb-doped La0.6Sr0.4FeO3-δ as an electrolyte for intermediate-temperature solid oxide fuel cells.

It is one of the effective strategies to develop intermediate-temperature solid oxide fuel cells (IT-SOFCs) by looking for alternative electrolyte materials that can maintain or even improve current cell efficiencies while reducing operating temperature. In this study, by rationally introducing pentavalent Nb on the B-site of La0.6Sr0.4FeO3-δ (LSFO), a serial of novel perovskite La0.6Sr0.4Fe1-xNbxO3-δ (LSFNbx, x = 0.1, 0.2) with mixed electron-ion conduction is successfully prepared. The electrochemical mechanism and performance of the symmetrical IT-SOFCs with a single LSFNbx perovskite oxide as electrolyte are investigated. With the Nb doping, the structure stability of the LSFO is improved and the electronic conductivity decreases. La0.6Sr0.4Fe0.8Nb0.2O3-δ (LSFNb20) is the most promising electrolyte of the three candidates as it has the best performance (735 mW cm-2 at 550 °C in a dry H2/Air atmosphere) and no short-circuiting problem. The applied voltage-response current curves demonstrate that the interface between the Ni-Ni0.8Co0.15Al0.05LiO2-δ anode and LSFNb20 electrolyte can block electron conduction more efficiently and has a better promoting effect on protons, which is fundamentally due to the band energy alignment of the interface heterojunction. Our work highlights that LSFNb20 is a high-performance perovskite alternative to monolayer electrolytes.

Development of La1.7Ca0.3Ni1-yCuyO4+δ Materials for Oxygen Permeation Membranes and Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells.

The La1.7Ca0.3Ni1-yCuyO4+δ (y = 0.0-0.4) nickelates, synthesized via a solid-state reaction method, are investigated as prospective materials for oxygen permeation membranes and IT-SOFC cathodes. The obtained oxides are single-phase and possess a tetragonal structure (I4/mmm sp. gr.). The unit cell parameter c and the cell volume increase with Cu-substitution. The interstitial oxygen content and total conductivity decrease with Cu-substitution. The low concentration of mobile interstitial oxygen ions results in a limited oxygen permeability of Cu-substituted La1.7Ca0.3NiO4+δ ceramic membranes. However, increasing the Cu content over y = 0.2 induces two beneficial effects: enhancement of the electrochemical activity of the La1.7Ca0.3Ni1-yCuyO4+δ (y = 0.0; 0.2; 0.4) electrodes and decreasing the sintering temperature from 1200 °C to 900 °C. Enhanced electrode activity is due to better sintering properties of the developed materials ensuring excellent adhesion and facilitating the charge transfer at the electrode/electrolyte interface and, probably, faster oxygen exchange in Cu-rich materials. The polarization resistance of the La1.7Ca0.3Ni1.6Cu0.4O4+δ electrode on the Ce0.8Sm0.2O1.9 electrolyte is as low as 0.15 Ω cm2 and 1.95 Ω cm2 at 850 °C and 700 °C in air, respectively. The results of the present work demonstrate that the developed La1.7Ca0.3Ni0.6Cu0.4O4+δ-based electrode can be considered as a potential cathode for intermediate-temperature solid oxide fuel cells.

Preparation and characterization of La2-xSmxMo1.8Al0.2O8.7 as electrolyte for solid oxide fuel cells

Solid oxide fuel cells (SOFCs) have been regarded as promising eco-friendly power sources in recent years owing to their high energy conversion efficiency and fuel flexibility. La2Mo2O9-based ceramics draw researchers’ attention due to their good performance as electrolyte materials for SOFCs. In this study, the Sm and Al co-doped La2Mo2O9, La2-xSmxMo1.8Al0.2O8.7 (x=0.1,0.2,0.3 and 04, LSMAO), are successfully synthesized by the sol-gel method as electrolyte materials for SOFCs. The phase evolution, sintering, the microstructural and electrochemical performance of LSMAO were observed by TG-DSC, XRD, SEM, and impedance analyses, respectively. The results show that the highly phase-pure cubic LSMAO nanopowders can be obtained after calcining at 600 °C for 2 h. The as-synthesized LSMAO powders exhibited a better sintering activity. All these samples were found to have a relative density above 94.5% after sintering at 950 °C for 5 h. The electrical performance study shows that higher doping concentrations of Sm caused a decrease in ionic conductivity and an increase in activation energy. La1.9Sm0.1Mo1.8Al0.2O8.7 exhibited the highest oxide ionic conductivity (σ800 °C=0.033 S/cm) and lowest electrical activation energy (Ea=0.85 eV). This shows that LSMAO could be used as a potential electrolyte for intermediate temperature SOFCs (IT-SOFCs).

Physiochemical and Electrochemical Properties of Lanthanum Strontium Cobalt Ferum–Copper (II) Oxide Prepared via Solid State Reaction

Lanthanum strontium cobalt ferum (LSCF) with addition of copper oxide (CuO) can serve as an alternate cathode material in Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) due to its strong catalytic activity for oxygen reduction process at intermediate temperatures and great chemical compatibility. This study was done to determine the viability of LSCF–CuO composite as a material for the IT-SOFC cathode. The cathode powder was synthesised using the conventional solid-state process at intermediate temperatures range (600ºC–900ºC). The thermogravimetric analysis demonstrated that when LSCF was calcined at temperatures over 600ºC, the weight loss curve flattened. In the meantime, x-ray diffraction revealed that the perovskite structure of LSCF-CuO was completely formed after calcined at 800ºC. Moreover, the Brunauer– Emmett–Teller (BET) and scanning electron microscope investigations demonstrated that as the calcination temperature rose, the LSCF–CuO particles tended to grow. The electrochemical impedance spectroscopy investigation revealed polarisation resistance of samples calcined at 800ºC (0.41 Ωcm2) was significantly lower than that of samples calcined at 600ºC (29.57 Ωcm2). Judging from chemical, physical and electrochemical properties, it is evidence that LSCF-CuO prepared via simple solid-state reaction has a potential to be used as cathode material for IT-SOFC.

Doped BSCF cathode materials for low-temperature solid oxide fuel cell applications-A short review

Fuel cell is used to produce electric energy through electrochemical process by energy conversion from chemical to electrical. Unlike conventional fuel combustion, fuel cell technology does not involve combustion process and completely eliminates the issues resulted from combustion emissions. Solid oxide fuel cell (SOFC) contains electrolytes which conduct oxide-ions. Higher efficiency, economically lower material cost and lower sensitivity against the impurities are the benefits with SOFC. Low-temperature (LT) or intermediate temperature SOFC is attractive because of its low value of working temperature (500–800 °C). Reducing the degradation of component, improvement of cell durability and less cost are the significant advantages with LT-SOFC. In the electrochemical reduction in LT-SOFC, cathode material plays an important role. BSCF cathode that contains Ba, Sr, Co and Fe as the important elements is widely used in LT-SOFC development due to its attractive performance. This article presents a brief review on various elements doped BSCF cathode materials and their performance. The importance of these elements on BSCF cathode properties is discussed and summarized.

Nanocomposite Catalyst for High-Performance and Durable Intermediate-Temperature Methane-Fueled Metal-Supported Solid Oxide Fuel Cells.

CH4-fueled metal-supported solid oxide fuel cells (CH4-MS-SOFCs) are propitious as CH4 is low-priced and readily available, and its renewable production is possible, such as biomethane. However, the current CH4-MS-SOFCs suffer from either poor power density or short durable operation, which is ascribed to the low catalytic activity and poor coking tolerance of the metallic anode support. Herein, we have deliberately designed and synthesized a highly active nanocomposite catalyst, Sm-doped CeO2-supported Ni, as the internal steam methane reforming catalyst, to optimize CH4-MS-SOFCs. Both power densities and durability of optimized CH4-MS-SOFCs have been dramatically enhanced compared to the pristine CH4-MS-SOFCs. The optimized CH4-MS-SOFCs deliver the highest performances among all zirconia-based CH4-MS-SOFCs. Furthermore, the operating temperature has been reduced to 600 °C. At 600 °C, a viable peak power density of >350 mW/cm2 is achieved, which is more than three times as high as the pristine CH4-MS-SOFCs. Furthermore, the optimized CH4-MS-SOFC achieves >1000 h of stable operation.

Gluing Ba0.5Sr0.5Co0.8Fe0.2O3−δ with Co3O4 as a cathode for proton-conducting solid oxide fuel cells

The Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) + Co3O4 composite material is evaluated as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs), which provides a new strategy to solve the thermal mismatch problem between the cathode and electrolyte without impairing the cathode performance. BSCF is a well-known cathode material for intermediate-temperature SOFCs, but its performance for H-SOFCs is unsatisfactory. One reason for the relatively low performance is the poor contact between the BSCF cathode and the electrolyte due to the high thermal expansion of BSCF. The relatively low melting point of Co3O4 is taken in this study as an advantage to bond the BSCF cathode to the electrolyte, mitigating the poor contact problem for the BSCF with the electrolyte. Furthermore, the addition of Co3O4 promotes the catalytic activity of the BSCF cathode as demonstrated by experimental studies and first-principles calculations, leading to an impressively high performance of BSCF-based cathodes for H-SOFCs.

Preparation and characterization of highly active and stable NdBaCo0.8Fe0.8Ni0.4O5+δ oxygen electrode for solid oxide fuel cells

In order to develop high active and stable oxygen electrode for intermediate temperature solid oxide fuel cells (IT-SOFCs), NdBaCo0.8Fe0.8Ni0.4O5+δ (NBCFN) oxygen electrode was successfully prepared by sol-gel method. The NBCFN sample formed a double perovskite structure after calcination at 1100 °C for 10 h. The NBCFN electrode and La0.9Sr0.1Ga0.83Mg0.17O3-δ (LSGM) electrolyte has good chemical compatibility below 950 °C. Compared with NdBaCo2O5+δ, the average thermal expansion coefficient (TEC) of NBCFN sample was 17.2 × 10−6 K-1 at 30 °C - 850 °C in air and decreased by 30%. The conductivity of NBCFN sample exhibited p-type semiconductor conduction and reached 441.8 S cm−1 at 800 °C. The polarization impedance (RP) of NBCFN oxygen electrode on LSGM electrolyte reached 0.055 Ω cm2 at 700 °C. The charge transfer process of NBCFN oxygen electrode was mainly rate-limiting step. The RP of NBCFN oxygen electrode exhibited good stability in air during 200 h test. At 800 °C, the NBCFN oxygen electrode on 300μm-thick LSGM electrolyte reached 1042 mWcm−2 at fuel cell mode and current density was 0.9 A cm−2 at 1.3 V under the electrolysis cell mode, respectively. These results primarily indicated that NBCFN oxygen electrode had good electrochemical performance for IT-SOFCs.

The synthesis of Eu–Tb–Ho co–doped Bi2O3–based ceramic powders for use in intermediate temperature–SOFCs

In this study, the solid–state reactions in the ambient atmosphere were used to produce Ho–Tb–Eu co–doped Bi2O3 solid ceramic powder solutions. All samples were stabilized with the cubic δ–phase, according to XRD patterns generated at room temperature. The main peak (111) on the diffraction pattern shifted to larger angles as the total dopant concentration increased, and the average crystal size decreased as well. On the temperature–based DTA curves, neither an endothermic nor an exothermic peak could be seen, indicating that no phase transition took place during the uniform heating circle. According to the conductivity measurement results, sample 5Eu5Tb15Ho had the highest conductivity of 0.288 S/cm at 750 °C and the lowest activation energy of 0.19 eV. The FE–SEM images revealed that the grain size of sample 5Eu5Tb15Ho and Ho–rich samples was not uniform across the surface, and the grain boundary line changed rapidly as the dopant concentration increased.

Investigation on high entropy alloys as interconnect material for intermediate temperature solid oxide fuel cells

Investigation of Solid Oxide Fuel Cells (SOFCs) is receiving great attention due to its higher efficiency and zero environmental pollution during operation. Interconnects are a critical part of the SOFC stack which connects the cells in series and combines the electricity produced. The present study aims to investigate High Entropy Alloys (HEAs) for interconnect application in intermediate temperature SOFC. Towards this, FeCoCrNi, FeCoCrNiMn0.1, FeCoCrNiMn0.5, and FeCoCrNiMn HEAs are prepared by vacuum arc melting and examined for its phase evaluation. Thermal stability, thermal expansion, resistivity, oxidation, and Area Specific Resistance (ASR) are investigated up to 800 °C. Oxidation studies show the formation of multicomponent oxide in the HEAs which suppresses the growth of Cr2O3 layer. FeCoCrNiMn0.1, FeCoCrNiMn0.5, and FeCoCrNiMn HEAs possess ASR values less than 100 mΩ.cm2 in the temperature range of 600–800 °C which ensure the superior performance of the SOFC stack.

Performance Evaluation of An Electrolyte-Supported Intermediate-Temperature Solid Oxide Fuel Cell (IT-SOFC) with Low-Cost Materials

Intermediate temperature solid oxide fuel cell (IT-SOFC) provides economic and technical advantages over the conventional SOFC because of the wider material use, lower fabrication cost and longer lifetime of the cell components. In this work, we fabricated electrolyte-supported IT-SOFC using low-cost materials such as calcia-stabilized zirconia (CSZ) electrolyte fabricated by dry-pressing, NiO-CSZ anode and Ca3Co1.9Zn0.1O6 (CCZO) cathode produced through brush coating technique. According to the XRD result, the monoclinic phase dominated over the cubic phase, and the relative density of the electrolyte was low but the hardness of the CSZ electrolyte was close to the hardness of commercial 8YSZ electrolyte. The performance of the single cell was performed with hydrogen ambient air. An open-circuit voltage (OCV) of 0.43, 0.46, and 0.45 V and a maximum power density of 0.14, 0.50, and 1.00 mW/cm2 were achieved at the operating temperature of 600, 700, and 800 °C, respectively. The ohmic resistance of the cell at 700 and 800 °C achieved 81.5 and 33.00 Ω, respectively due to the contribution of thick electrolyte and Cr poisoning in electrodes and electrolyte

Understanding electrocatalytic activity of titanium and samarium doped ceria as anode material for solid oxide fuel cells

• Titanium and samarium stabilized ceria (Ce 0.73 Ti 0.07 Sm 0.2 O 2-δ (STDC)) prepared by urea combustion method. • Proposed anode material shows nearly 4 times enhancement in surface area. • H 2 -TPR results indicates incorporation of Ti in Sm stabilized ceria promotes low temperature reduction. In the present work, titanium and samarium doped ceria (Ce 0.73 Ti 0.07 Sm 0.2 O 2-δ , (STDC)) is evaluated as potential anode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). The anode and electrolyte (Ce 0.8 Sm 0.2 O 2-δ, (SDC20)) materials are synthesized using urea combustion method. The desired phase formed is confirmed by powder X-ray diffraction (XRD). The textural study is performed using Brunauer–Emmett–Teller method. STDC shows nearly 4 times enhancement in surface area and higher mesopores compared with SDC20. The effect of titanium on chemical environment of cerium is investigated using X-ray Photoelectron Spectroscopy. Both + 3 and + 4 valence states of cerium exist, which indicate high oxygen non-stoichiometry present in the synthesized samples. The morphological features are investigated using Scanning Electron Microscopy/High-Resolution Transmission Electron Microscopy. Electrolyte supported cell is fabricated using cold-pressing and spin coating of electrode and co-firing of cell. Fuel cell tests with 5 % H 2 (95 % N 2 ) as a fuel demonstrate Ce 0.73 Ti 0.07 Sm 0.2 O 2-δ -NiO as a potential anode material for IT-SOFCs.

(Digital Presentation) Reactive Magnetron Sputtering Deposition of La1.6Nd0.4NiO4 Coating As Cathode for Solid Oxide Fuel Cell

Ln2NiO4 (Ln=La, Pr, Nd, etc.) materials with K2NiF4 structures are interesting materials for intermediate temperature solid oxide fuel cell (IT-SOFC) due to Mixed Ionic and Electronic Conductivity (MIEC) [1-2]. The present work is focused on the elaboration of La1.6Nd0.4NiO4 coating obtained by Reaction Magnetron Sputtering (RMS). This compound is a promising oxygen electrode able to decrease the operating temperature of SOFC. After a presentation of the deposition operating conditions for obtaining the films, the structural and microstructural characterizations of the coatings were, respectively, determined by XRD and SEM. The electrical properties were studied as a function of temperature by the 4-probe method. Electrochemical properties were investigated in a symmetrical cell electrode / YSZ / electrode by complex impedance spectroscopy. Finally, a complete cell composed of a commercial anode, and YSZ electrolyte made by RMS and the cathode of this study was tested under hydrogen and air in single SOFC cell configuration.It appeared that the films are amorphous when processed and that they crystallize after an annealing treatment under air. According to this study, a correlation between crystalline structure, morphology and electrical properties will be presented and its last ones are completed by a thermogravimetry analysis.

Ekspansi Termal, Oxygen Content, dan Sifat Elektrokimia Oksida SmBa0.5Sr0.5Co2O5+δ (70%) + SDC (30%) Sebagai Katoda SOFC

The thermal properties of the double perovskite SmBa0.5Sr0.5Co2O5+δ (70%) + SDC (30%) have been investigated as potential cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFC). This study also includes the oxygen content and electrochemical performance of long-term tests carried out to evaluate the electrochemical stability. Cathode powder is fabricated by a simple and relatively inexpensive solid-state reaction. Oxygen content decreased gradually from room temperature to 800oC by 18.3%. Doping 30% SDC into SBSC oxide can reduce the thermal expansion coefficients (TEC) value from 19.80 x 10-6 (K-1) to 18.17 x 10-6 (K-1) or a decrease of 8.23%. The activation energy (Ea) identified by the electrochemical impedance spectroscopy (EIS), low field (LF), and high field (HF) techniques were 125.3 kJ mol-1, 60.6 kJ mol-1, and 62.5 kJ mol-1, respectively. The SBSC73|SDC|SBSC73 symmetric cell test for 96 hours at 600oC showed an increase in the average polarization resistance value of 0.30% h-1. The cathode grains are evenly distributed with a size of 2-3 µm and tend to be porous. These results exhibit that SmBa0.5Sr0.5Co2O5+δ (70%) + SDC (30%) is a promising cathode material for IT-SOFCs.