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The Crofer 22 H ferritic steel substrate was coated with an Mn1.45Co1.45Cu0.1O4 spinel by means of electrophoresis. After high-temperature oxidation under thermal cycling conditions, the physicochemical properties of the obtained system were evaluated. During 48-h cycles that involved heating the samples up to temperatures of either 750 or 800 °C, the oxidation kinetics of both coated and unmodified steel approximately obeyed the parabolic rate law. The unmodified steel was oxidized at a higher rate than the system consisting of the substrate and the coating. In its bulk form, the spinel consisted entirely of the cubic phase and it exhibited high electrical conductivity. The Mn1.45Co1.45Cu0.1O4 coating, on the other hand, was compact and consisted of two phases—the cubic and the tetragonal one—and it was characterized by good adhesion to the metallic substrate. After cyclic oxidation studies conducted for the two investigated temperatures (750 or 800 °C), the coating was determined to provide a considerable improvement in the electrical properties of the Crofer 22 H ferritic steel, as demonstrated by the area-specific resistance values measured for the steel/coating system. The evaporation rate of chromium measured for these samples likewise indicates that the coating is capable of acting as an effective barrier against the formation of volatile compounds of chromium. The Mn1.45Co1.45Cu0.1O4 spinel can therefore be considered a suitable material for a coating on the Crofer 22 H ferritic steel, with intermediate-temperature solid oxide electrolyzer cells as the target application.

In the study, the surface of the Crofer 22APU ferritic steel was modified with gadolinium oxide nanoparticles and a protective-conducting layer consisting of the MnCo2O4 spinel. This system was studied in the context of application in IT-SOFC interconnects. Four types of samples were studied: unmodified steel, steel coated with a manganese-cobalt spinel layer, steel modified with gadolinium oxide nanoparticles, and a system consisting of steel after both modifications. Steel samples with Gd2O3 nanoparticles were obtained via dip-coating, while the spinel coatings were deposited electrophoretically. All samples were oxidized for 1000 and 2260 h in air at 1073 K. Microstructural and oxidation kinetics studies revealed that gadolinium segregation at grain boundaries in the Cr2O3 scale between the steel and the spinel layer reduces the oxidation rate for the steel/coating system, thereby improving the adhesion of the scale to the substrate. The applied modification decreased the chromium evaporation rate and improved the electrical properties of the interconnect material.

Spinel oxides with the general formula Mn1.7Cu1.3-xFexO4 (x= 0, 0.1, 0.3, 0.5) were prepared and evaluated in this work for their properties at high temperatures. The effect of partially substituting Cu by Fe has not been studied so far for this group of materials and is thus evaluated in this work. Mn1.7Cu1.3-xFexO4 powders were synthesised by a soft chemistry process and studied in terms of crystallographic phase analysis, electrical conductivity, thermal expansion, and sinterability behaviour. The results show that the Fe content has a significant influence on the phase composition and the resulting properties. Characterisation of the dilatometry and conductivity coupled with XRD phase analysis across a wide temperature range allowed the relations between the materials properties and compositions to be observed. The results indicate that Mn1.7Cu0.8Fe0.5O4 is a promising material for use as a protective coating for interconnects in intermediate temperature Solid Oxide Fuel Cells.

Ce0.8Gd0.2O1.9 (CGO) barrier layers are required to mitigate the chemical reactions between Sr-containing oxygen electrode materials and Zr-based oxygen ion conductors in high-temperature solid oxide cells. Barrier layers produced by different methods were studied in this work. As a reference, a cell with no barrier layer was measured. The application of the powder-processed barrier layers, considerably increases the performance. For further comparison, thin and dense CGO layers were produced by a low-temperature spray pyrolysis process. Three different thicknesses were evaluated: ∼300 nm, ∼700 nm and ∼1500 nm. The best performance was found for the ∼700 nm thick CGO barrier layer. It showed low ohmic and polarisation resistances. The low thickness and high density of the CGO barrier layer were found to be the important factors. The cells with the ∼700 nm CGO barrier layers were also evaluated for their electrolysis performance as well as fuel cell durability.

This work evaluates the effects of the sintering temperature (800 °C, 900 °C, 1000 °C) of SrTi1-xFexO3-δ (x = 0.35, 0.5, 0.7) porous electrodes on their electrochemical performance as potential oxygen electrode materials of solid oxide cells. The materials were prepared by a solid-state reaction method and revealed the expected cubic perovskite structure. After milling, the powders were characterised by a sub-micrometre particle size with high sinter-activity. It was shown that the lowest area specific resistance was achieved after sintering SrTi0.65Fe0.35O3 electrodes at 1000 °C, and SrTi0.5Fe0.5O3 and SrTi0.30Fe0.70O3 electrodes at 800 °C, which can be considered to be a relatively low temperature. In general, EIS measurements showed that increasing the Fe content results in lowered electrode polarisation and a decrease of the series resistance. Even though the studied materials have much lower total conductivities than state-of-the-art electrode materials (e.g. (La,Sr)(Co,Fe)O3), the polarisation resistances obtained in this work can be considered low.

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.

Fe-doped Mn1,5Co1,5O4 coatings on Crofer22APU were processed by an electrophoretic co-deposition method and the corrosion resistance was tested at 750 °C up to 2000 hours.The “in-situ” Fe-doping of the manganese cobalt spinel was achieved by electrophoretic co-deposition of Mn1,5Co1,5O4 and Fe2O3 powders followed by a two-step reactive sintering treatment. The effects on the coating properties of two different Fe-doping levels (5 and 10 wt.% respectively) and two different temperatures of the reducing treatment (900 and 1000 °C) are discussed. Samples with Fe-doped coatings demonstrated a lower parabolic oxidation rate and thinner oxide scale in comparison with both the undoped Mn1,5Co1,5O4 spinel coating and bare Crofer 22 APU. The best corrosion protection was achieved with the combined effect of Fe-doping and a higher temperature of the reducing step at 1000 °C.

Some oxygen defective fluorites are non-Newnham electrostrictors, i.e., the electromechanical response does not depend on their dielectric properties. Here, we show gigantic electrostriction in nanocrystalline 25 mol% praseodymium doped ceria (PCO) bulk ceramics. The material was fabricated with a field-assisted spark plasma sintering (SPS) process from high-purity nanoscale PCO powders (< 20 nm). The SPS process consolidates the powders into a single-phase, highly dense material with a homogeneous microstructure and large grain boundary extension. Various thermally and chemically stable ionic defects are incorporated into the nanostructure, leading to superior electrical conductivity. The material shows an electrostriction strain coefficient (M33) of ~10−16 m2/V2 at frequencies below 100 Hz at room temperature. Such performance is comparable and even superior to Newnham's electrostrictors such as ferroelectric ceramics and polymeric actuators. Comparative analysis with polycrystals suggests that nanostructured PCO possesses electromechanically active nanodomains of Pr3+-VO pairs. Such results are unexpected and open novel insights on non-Newnham electrostrictors.

Solid oxide cells (SOCs) are electrochemical energy converters that can operate in two modes within one unit. In fuel cell mode (solid oxide fuel cell, SOFC), they directly convert chemical energy into electrical energy through a Knallgas reaction, which is the chemical reaction of oxygen and hydrogen forming water in a controlled manner. The opposite reaction, the splitting of water into hydrogen and oxygen, is the electrolysis reaction (solid oxide electrolysis cell, SOEC). The Knallgas reaction is exothermic, while the water splitting reaction is endothermic. SOCs today typically operate between 650°C and 900°C. Only three layers are required for the fundamental electrochemical reactions: an electrolyte and two electrodes—the anode (the positive pole) and the cathode (the negative pole). In this chapter, the fundamental reactions, the geometrical designs, the material requirements, and the status of SOFCs and SOECs are presented. In the following seven chapters, the most important components of an SOC are described and the chapter ends with a summary and outlook. The described components are: (i) oxygen-ion conductors (electrolyte), (ii) anode materials for SOFCs (cathode in SOEC mode), (iii) cathode materials for SOFCs (anode in SOEC mode), (iv) proton conductors and adjacent electrodes, (v) stack sealing materials, (vi) ceramic coatings for metal interconnects, and (vii) degradation effects limiting lifetime and performance.

Recent investigations have shown that highly oxygen defective cerium oxides generate non-classical electrostriction that is superior to lead-based ferroelectrics. In this work, we report the effect of field-assisted spark plasma sintering (SPS) on electro-chemo-mechanical properties of calcium doped ceria (CDC). Nanometric powders of Ca.10 nm are rapidly consolidated to form polycrystalline nanostructures with a high degree of crystalline disorder. Remarkably, the resultant material demonstrates a large electromechanical strain without a frequency-related relaxation effect. We conclude that electromechanical activity in CDC materials strictly depends on the Ca2+- V o ¨ interaction, while disorder at the crystalline boundaries has a minor effect.

We report a systematic microstructural and electrical characterization of iron doped Mn–Co spinel coatings processed by electrophoretic co-deposition of Mn1.5Co1.5O4 and Fe2O3 powders on Crofer 22 APU and AISI 441 steel substrates. Iron addition to Mn–Co spinel coating leads to a reduction of the area specific resistance on both substrates, after 3200 h at 750 °C. The Fe doped Mn–Co coating both leads to a thinner oxide scale and reduces the sub scale oxidation for the Crofer 22 APU substrate. Fe doped Mn–Co on AISI 441 shows both a thicker oxide scale and low area specific resistance values, likely due to a doping effect of the oxide scale by minor alloying elements. The different mechanisms by which iron doping of Mn–Co spinels can influence elemental interdiffusion at the steel-oxide scale-coating interfaces and relative contributions to the overall area specific resistance are evaluated by means of advanced electron microscopy. The promising results are further confirmed in a cell test, where the Fe doped MnCo coated interconnect does not induce any degradation of the oxygen electrode, proving its efficiency.

In this work manganese cobalt spinel (MnCo2O4) coatings were deposited on steel substrates by spray pyrolysis at 390 °C. This is at much lower temperatures than previously reported (typically in excess of 900 °C). It was possible to produce coatings with well controlled thickness (2-5-10 μm). The as-deposited coatings were evaluated for their microstructural changes and electrical conductivity up to 800 °C. Results confirm the formation of a single phase spinel with high density and electrical conductivity. Based on the obtained results, it might be concluded that spray pyrolysis is a very promising method to develop protective coatings for steel substrates at low temperatures overcoming limitations of many other methods.

In this work, the infiltration technique was used to produce hydrogen electrodes for solid oxide cells. Different infiltration methodologies were tested in order to try to shorten the infiltration cycle time. The porous scaffolds used for infiltration were based on highly porous yttria-stabilized zirconia (YSZ) obtained by etching the reduced nickel from the Ni-YSZ cermet in HNO3 acid. The support had a complex structure which included a ~130 µm porous functional layer with small pores and a ~320 µm thick supporting layer with large pores. Infiltrations have been carried out using aqueous nickel nitrate solutions. Various infiltration procedures were used, differing in temperature/time profiles. The results show that slow evaporation is crucial for obtaining a homogeneous material distribution leading to high-quality samples. A longer evaporation time promotes the proper distribution of nickel throughout the porous scaffold. The shortening of the heat treatment procedure leads to blockage of the pores and not-uniform nickel distribution.

Gadolinium doped ceria (Ce 0.8 Gd 0.2 O 2 − x -CGO) layer fabricated by spray pyrolysis is investigated as the diffusion barrier for solid oxide fuel cell. It is deposited between the La 0.6 Sr 0.4 FeO 3 − δ cathode and the yttria stabilized zirconia electrolyte to mitigate harmful interdiffusion of elements. The parameters of the fabrication process are linked to the measured area specific resistances of the symmetrical cells and the efficiency of the fuel cells. Results show, that application of 800 nm thick barrier effectively hinder negative reactions, while 400 nm thick layer is sufficient to prevent degradation of the Ohmic resistance.

In this work, novel functional layers were prepared by a low temperature spray pyrolysis method on the oxygen side of the solid oxide cells. Thin layers of Ce0.8Gd0.2O2 and LaNi0.6Fe0.4O3 are prepared between the electrolyte and the porous oxygen electrode. Additionally the influence of the sprayed ceria barrier layer on the zirconia based electrolyte with the new layers is evaluated. Impedance spectroscopy results show improvement in contact between the electrolyte and the porous cathode electrode. Additionally, electrochemical performance of the cathode is improved, as evidenced by a lowered area specific resistance and increased power density obtained from an anode supported cell employing the new layer.

In this study two materials, MnCo 2 O 4 and MnCo 1.8 Fe 0.2 O 4 are studied as potential protective coatings for Solid Oxide Fuel Cell interconnects working at 750 °C. First powder fabrication by a modified Pechini method is described followed by a description of the coating procedure. The protective action of the coating applied on Crofer 22 APU is evaluated by following the area specific resistance (ASR) of the scale/coating for 5500 h including several thermal cycles. The coating is prepared by brush painting and has a porous structure after deposition. Post mortem microstructural characterization performed on the coated samples shows good protection against chromium diffusion from the chromia scale ensured by a formation of a dense reaction layer. This study shows, that even without high temperature sintering and/or reactive sintering it is possible to fabricate protective coatings based on MnCo spinels.

The Cu doping of the Mn–Co spinel is obtained “in-situ” by electrophoretic co-deposition of CuO and Mn 1.5 Co 1.5 O 4 powders and subsequent two-step reactive sintering. Cu-doped Mn 1.5 Co 1.5 O 4 coatings on Crofer22APU processed by electrophoretic co-deposition method are tested in terms of long term oxidation resistance and area specific resistance tests up to 3600 h. The introduction of Cu in the spinel lead to higher level of densification of coatings for all the considered aging periods at 800 °C and stabilizes the cubic phase of the Mn 1.5 Co 1.5 O 4 spinel. Corrosion rate of the Cu-doped Mn 1.5 Co 1.5 O 4 coated Crofer22APU is ∼10x lower than for the uncoated Crofer22APU. The stabilization of the cubic phase due to Cu doping, which reduces the extent of the tetragonal-cubic phase transition and limits possible thermal stresses due to mismatch of coefficients of thermal expansion or volume changes, is reviewed and discussed by means of electrical conductivity measurements together with diffraction patterns and elemental analyses. These novel electrophoretic co-deposited Cu-doped MnCo spinel coatings represent an innovative approach to obtain coatings with higher density and have future applications in the view of reaching lower rates of Cr evaporation form the steel.

Intermediate temperature solid oxide fuel cells oxygen electrodes are modified by active interfacial layers. Spray pyrolysis is used to produce thin (≈500 nm) layers of mixed ionic and electronic conductors: Sm0.5Sr0.5CoO3−δ (SSC), La0.6Sr0.4CoO3−δ (LSC), La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF), and Pr6O11 (PrOx) on the electrode–electrolyte interface. The influence of the annealing temperature on the electrode polarization (area specific resistance—ASRpol) is investigated by impedance spectroscopy of symmetrical electrodes in the temperature range of 400–700 °C. The results show that the introduction of nanocrystalline interlayers promotes an oxygen reduction reaction by extending the active surface area and improved contact between the electrode and the electrolyte. Introducing LSCF, LSC, or SSC interlayer reduces ASRpol by a factor of 4 and PrOx by a factor of 2 against the reference, powder processed LSCF electrode. At 600 °C, the obtained ASRpol values for PrOx, LSCF, LSC, and SSC interlayer are 245, 137, 119, and 107 mΩ cm2, which can be considered very low in comparison to standard powder processed oxygen electrodes. Anode supported single cell with developed LSC/LSCF electrode reveals ≈1.2 W cm−2 power output at 600 °C and maintains stable cell voltage of 0.75 V under 1 A cm−2 during 60 h of the test.

Widespread commercialization of solid oxide fuel cells requires lowering its cost. It is generally accepted that to lower the cost of solid oxide fuel cells it is necessary to use metal alloys as interconnectors and, consequently, lower its operating temperature to slow down interconnectors degradation. As a result the area specific resistance of the cathodes should be lowered to sustain the performance of the cells. In order to slow the interconnectors degradation (due to corrosion and interdiffusion with the anode) and improve the performance of the cathodes, novel functional layers are introduced to the structure of the fuel cells. In this paper, results related to three kinds of functional layers will be presented: a thin cathode layer between the porous cathode layer and the electrolyte to improve the cathode performance, a buffer layer between the electrolyte and the cathode to slow down inter-diffusion of atoms and thin and dense interconnector coatings to slow down interconnectors degradation. The investigated layers are deposited by cost effective spin coating and spray pyrolysis methods. Introduction of the layers show positive and promising results.

High purity nanoscale powders (~10–15 nm size) of two different compositions of ceria, doped with Gd3+ and Ca2+, have been consolidated by spark plasma sintering (SPS) at different temperatures. Fully-dense samples were observed only at a sintering temperature of 980 °C. The as-sintered samples showed rather fast grain growth with an average grain size below 300 nm. The electrical properties of the samples were evaluated by impedance spectroscopy over a wide range of temperatures (300–550 °C) in air. Electrical conductivity significantly enhanced with increasing sintering temperature. The compounds show an electrical blocking effect at the grain boundary, depending on the doping cations.

In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a &beta, phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2&middot, g&minus, 1, a pore volume of 0.0042 cm3&middot, 1, and high electrochemical stability with an overpotential deviation around 330&ndash, 340 mV at 10 mA&middot, cm&minus, 2geo for 70 h.

This work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 °C and 600 °C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after 600 °C, the electrochemical performance decreases considerably.

Co-deposition of CuO and Mn1.5Co1.5O4 by single step electrophoretic deposition is used to produce ∼15 µm coatings on Crofer22APU steel, which finds use as interconnect for high temperature solid oxide cells. Sintering of the green coatings in reducing and then oxidizing conditions led to formation of a mixed (Cu,Mn,Co)3O4 spinel. By the incorporation of Cu, the density of the coatings improved. Scanning and transmission electron microscopy observations, supplemented with energy dispersive spectroscopy, confirmed dissolution of Cu in the spinel phase. For the un-doped Mn1.5Co1.5O4 both the tetragonal and cubic phases are detected at room temperature by X-ray diffractometry, whereas the addition of Cu seems to stabilize the cubic phase. Initial (∼1000 h) high temperature corrosion evaluation at 800 °C in air showed promising properties of the mixed spinel coating.

Cr-containing stainless steels are widely used as metallic interconnects for SOFCs. Volatile Cr-containing species, which originate from the oxide formed on steel, can poison the cathode material and subsequently cause degradation in the SOFC stack. Mn 1.5 Co 1.5 O 4 spinel is one of the most promising coating materials due to its high electrical conductivity, good CTE match with the stainless steel substrate and an excellent chromium retention capability. In this work Mn 1.5 Co 1.5 O 4 spinel coatings are deposited on Crofer22APU substrates by cathodic electrophoretic deposition (EPD) followed by sintering at 800–1150 °C in different atmospheres. Dense, continuous and crack free Mn 1.5 Co 1.5 O 4 coatings (with thickness ranging from 10 to 40 μm) are obtained on Crofer22APU substrates. Moreover, electrical properties of the coated Crofer22APU alloy are tested up to 2500 h and an excellent compatibility is found between Mn 1.5 Co 1.5 O 4 coated Crofer22APU and a new glass-ceramic sealant, after 500 h of thermal tests in air, thus suggesting that the spinel protection layer can effectively act as a barrier to outward diffusion of Cr.

Anode-supported solid oxide fuel cell with SrTi0.98Nb0.02O3–d anode, yttria-stabilized zirconia electrolyte and La(Ni0.6Fe0.4) O3d cathode has been successfully fabricated and evaluated. Process of anode support fabrication has been presented. Wet powder spraying and high temperature sintering method have been studied and applied to deposit the thin electrolyte layer.In order to improve catalytic properties of the anode, it has been impregnated with Ni. Electrical properties of fuel cells have been measured to determine their performance. The open cell voltage of 1.08V and maximum power density at the level of 160mWcm2 were observed at 800 8C.

Niobium-doped strontium titanate was used as the anode for a solid oxide fuel cell. Electrolyte-supported cells were prepared with pure perovskite and composite perovskite–yttria–stabilized-zirconia (YSZ) anodes. Fuel cell tests demonstrated significant improvement in power density after infiltration with a small amount of Ni. The obtained values of power densities are comparable with conventional Ni/YSZ cermet anode. In addition, stability tests showed initial degradation followed by stable operation.

Doped strontium titanates are very versatile materials. Iron doped SrTiO3 can be used, for example, as a material for resistive gas sensors and fuel cell electrodes. In this paper, two compositions based on Fe doped SrTiO3 were studied as possible candidates for cathode application in SOFCs. Namely, SrTi0.65Fe0.35O3 and SrTi0.50Fe0.50O3 were examined. A chemical reactivity between electrode and YSZ electrolyte material was investigated, since Sr containing cathode materials in contact with YSZ electrolyte are prone to form insulating phases. Electrical conductivity of bulk samples showed relatively low total conductivities of 0.4 S cm−1 and ~2 S cm−1 for STF35 and STF50 respectively. Suitability for cathode application was studied by Electrochemical Impedance Spectroscopy in a symmetrical electrode configuration. Area specific resistance (ASR) was determined in the temperature range from 600°C to 800°C. At 790°C samples show polarization ASR of approximately 0.1 Ω cm2. It can be expected that further reduction of electrode ASR can be obtained by introduction of ceria barrier layer and tailoring of the electrode microstructure.

Porous alloys are proposed as supports for the next generation solid oxide fuel cells. Their application lowers the price of the fuel cells, which will result in faster commercialization. However, they are prone to high temperature corrosion. So far, there is lack of methods, which can improve high temperature properties of porous alloys for SOFC applications. A method for improving corrosion resistance of porous alloys has been proposed and investigated here. In this work protective coatings are prepared by the infiltration of precursor solutions that contain Y cations. High temperature oxidation properties of the modified alloys are compared with non-modified samples by cyclic thermogravimetry, electron microscopy and X-ray diffractometry measurements. The infiltration of Y precursor into the porous alloy decreases the high temperature corrosion rate. This method can be used to improve long term properties of porous alloys applied for fuel cells supports.

In this work, slurry spraying is evaluated as a deposition method of thin electrolytes for solid oxide fuel cells. This method is cost effective, uncomplicated and have several advantages in respect to widely used screen printing method. Influence of deposition parameters: slurry concentration, spraying pressure are discussed. Anode supported cells are produced with three different electrolyte thicknesses: 5, 10 and 20 μm showing flexibility of the developed method. Prepared fuel cells achieve satisfactory power densities of almost 1 W cm-2 at 800°C. As evidenced by impedance spectroscopy, performance of cells is determined by the polarization resistance. Cross sections of cells show that all electrolyte layers are of high quality. Slurry spraying is a feasible method for fabrication of functional cells and can be easily scaled for large quantity production.

Metal-supported solid oxide fuel cells are regarded as a new generation of SOFC devices. The use of porous metal substrate provides a high mechanical strength of a SOFCs' support and lowers the cost of fuel cells. In this study, powders of PI600, 317L and 430L steel grades were used to prepare porous metallic supports. After sintering at different temperatures, their porosity and high temperature corrosion resistance were evaluated. Cyclic thermogravimetric analysis, X-ray diffractometry and SEM imaging were used to describe properties of these porous alloys. Electrical properties were studied for selected samples. The influence of porosity on resulting properties was elucidated. The porosity changes measured between oxidation cycles were presented. Results showed that the properties of porous alloys differ significantly from those of dense ones. The high temperature corrosion rate is high and is strongly influenced by the porosity level. Open porosity decreases rapidly upon oxidation at 800 °C. As an outcome of this study, the PI600 alloy performs best among those investigated; however, better corrosion resistant materials are needed for SOFCs' supports operating at 800 °C.

Proton-conducting ceramic oxides working in the temperature range from 500 °C to 900 °C may be applied in solid oxide fuel cells (SOFC), electrolysis cells, H 2 separators, gas sensors and other devices. In this work the first results of the studies of magnesium-doped La 0.98 Mg 0.02 NbO 4 electrolyte materials are presented. The structure, microstructure and electrical properties of the samples synthesized with the conventional solid-state method (SS) and the composite samples obtained with the TGG method are compared. The microstructure and electrical properties of the studied materials depended strongly on the synthesis method. The composite samples showed partial crystallographic orientation. It was proposed that owing to this, the conductivity of the composite samples was comparable or larger than that of other doped ortho-niobates.

Yttria stabilized zirconia electrolytes were sintered with addition of iron oxide or chromium oxide. The phase composition of the composites, sintering properties and DC and AC electrical properties are evaluated and compared with available data. Results show, that after sintering there is only single-phase material found in the XRD patterns. Iron can be considered as a sintering promoter while chromium decreases the apparently sintering process. Addition of either oxide decreases total electrical conductivity in comparison to pure samples. Based on impedance spectra it can be concluded that chromium mainly influences electrical conductivity of grain boundary, while iron influences electrical conductivity of both grain and grain boundary, with a solubility limit at grain boundaries estimated at about 2 mol% Fe.

In this paper a ceramic deposition method that does not require a high temperature sintering step is presented. The method is used for a fabrication of electrolyte layers for SOFCs and high temperature protective coatings of stainless steel. The preparation of polymeric precursors and ceramic slurries are described and structure evolution of the deposited layers during heat treatment is discussed. Application of described method might help in eliminating problems related to excessive steel corrosion of metal supported SOFCs or reaction between electrolyte and cathode during high temperature sintering process.

Perovskite oxides comprise large families among the structures of oxide compounds, and several perovskite-related structures are also known. Because of their diversity in chemical composition, properties and high chemical stability, perovskite oxides are widely used for preparing solid oxide fuel cell (SOFC) components. In this work a few examples of perovskite cathode and anode materials and their necessary modifications were shortly reviewed. In particular, nickel-substituted lanthanum ferrite and iron-substituted strontium titanate as cathode materials as well as niobium-doped strontium titanate, as anode material, are described. Electrodes based on the modified perovskite oxides are very promising SOFC components.