Development of Low-Cost Anode Material for Solid Oxide Fuel Cells

Research into the use of Rh and Ce0.80Gd0.20O1.90 (CGO20) co-impregnated La0.20Sr0.25Ca0.45TiO3 (LSCTA-) anodes for electrolyte-supported Solid Oxide Fuel Cells (SOFC) has yielded extremely impressive durability and robustness at industrial short stack scales over the past decade. These anodes have exhibited the ability to rival the degradation and RedOx/thermal/thermo-RedOx cycling tolerance of state-of-the-art SOFC anodes at short stack scales, in addition to providing the ability to operate under sulfur-laden fuel gas streams and high fuel utilisation/overload conditions. (1)Given the success of implementation of LSCTA- anodes into Electrolyte Supported Cells (ESC) and the reasonable mechanical strength of LSCTA- as a support material, (2,3) successful attempts have also been made to employ LSCTA- as an anode support for SOFC at button cell scales, (4,5) in addition to appraisal of the upscaling of thick-film ceramic processing techniques used to prepare larger (20 cm by 20 cm) SOFC anode supports. (3) These studies performed by Lu et al., Ni et al. and Verbraeken et al. (3-5) focussed upon production of LSCTA- anode supports by aqueous tape casting followed by either co-casting or screen printing of a 8 mol. % yttria-stabilised-zirconia (8YSZ) electrolyte layer.Therefore, using these studies as a basis for the current research, we present results concerning the ceramic processing of Anode Supported Cells (ASC) that employ LSCTA- anode ‘backbone’ microstructures, with the ultimate aim of testing SOFC whose anodes have been decorated with Rh and CGO20 catalysts through wet impregnation. Here, we detail a thermal compatibility study of a variety of electrode and electrolyte material sets using dilatometric analysis, leading to the conclusion that the shrinkages of LSCTA- and 8YSZ are sufficiently matched to allow co-sintering of the anode support and electrolyte layers. Subsequently, the thick-film aqueous ceramic processing of LSCTA- anode supports, via tape casting, is discussed in addition to an appraisal of the most appropriate method to produce dense 8YSZ electrolyte layers (i.e., electrolyte deposition by co-casting or screen printing), with the aim of co-sintering the structure up to 1400 °C in air. Finally, an evaluation of the microstructural characteristics of LSCTA − supports, prepared using a typical graphite pore former (commonly used with organic solvent systems) or without the use of a pore former, will be provided, in comparison to microstructures resulting from the incorporation of poly(ethyl/methyl methacrylate) pore formers that are compatible with the aqueous solvent system employed. References R. Price, M. Cassidy, J. G. Grolig, G. Longo, U. Weissen, A. Mai and J. T. S. Irvine, Adv. Energy Mater., 2003951, 1 (2021).V. Vasechko, M. Ziegner and J. Malzbender, Ceram. Int., 40, 13179 (2014).M. C. Verbraeken, B. R. Sudireddy, V. Vasechko, M. Cassidy, T. Ramos, J. Malzbender, P. Holtappels and J. T. S. Irvine, J. Eur. Ceram. Soc., 38, 1663 (2018).L. Lu, C. Ni, M. Cassidy and J. T. S. Irvine, J. Mater. Chem. A, 4, 11708 (2016).C. Ni, L. Lu, D. N. Miller, M. Cassidy and J. T. S. Irvine, J. Mater. Chem. A, 6, 5398 (2018).

Biomass gasification has acquired considerable interest as a sustainable and environmentally friendly way to produce heat, hydrogen or electricity from agro-industrial wastes or other kinds of biomass. A very effective solution for the achievement of high electrical efficiency (up to 55%) is the integration of biomass gasification with solid oxide fuel cell (SOFC) technology, including the necessary gas cleanup to avoid degradation of the SOFC. For this reason, this paper first shows in detail the risk and the impact of carbon deposition, exposure to tar, hydrogen sulphide, hydrogen chloride and alkali metals on SOFC anode and then, considering the tolerance limit for inorganic and organic contaminants (<1 ppmv for H2S, HCl and alkali and <10 ppmv for tar), offers an overview of the most relevant and effective technologies to remove these contaminants and to feed safely a SOFC system.

High operating temperature affords solid oxide fuel cells (SOFCs) fuel flexibility, favorable kinetics, enhanced transport properties and high quality heat for secondary thermodynamic cycles.1 Elevated temperatures, however, present challenges to ensuring cell durability.2 Coarsening of nickel in the Ni-YSZ anode is one such challenge that can lead to significant performance degradation. The fundamental driving force Δμ for coarsening phenomena is given by Eq. 1.3 The expression, which assumes isotropic interfacial energy, indicates that the chemical potential μ of a curved interface differs from that of a flat interface μ 0 by the factor VmγH, where H is mean curvature, γ interfacial energy and Vm molar volume. Δμ = μ - μ 0 = VmγH (1) Eq. 1 makes evident that variations in interface curvature, i.e., interface shape, directly correspond to variations in chemical potential. Furthermore, it follows from Eq. 1 that microstructural coarsening is fundamentally related to variations in interface shape. The link between interface shape and coarsening propensity is well known and methods have been developed to directly measure interfacial curvature distributions for complex morphologies in 3-D.4,5 In this work, these techniques are applied to 3-D images obtained by x-ray nanotomography to study coarsening in microstructures obtained from Ni-YSZ solid oxide fuel cell anodes aged for varying lengths of time. This work builds on a previous characterization of the same samples.6 The curvature measurements collected suggest that a combination of coarsening and morphological instability, which leads to channel pinch-off, severely diminish the connectivity of the anode’s Ni network and, in addition, lead to a significant loss of both nominal and effective triple-phase boundary (TPB) density. Both the loss of connectivity and TPB density coincide with cell performance degradation that was observed in the aging experiment7 from which the anode samples were taken. References Singhal, S. C.; Kendall, K. High Temperature Solid Oxide Fuel Cells, Elsevier, 2003.Yokokawa, H.; Tu, H.; Iwanschitz, B.; Mai, A. Fundamental mechanisms limiting solid oxide fuel cell durability. J. Power Sources 2008, 400-412.Voorhees, P. W. The Theory of Ostwald Ripening. J. Stat. Phys. 1985, 231-252.Glicksmann, M. E.; Voorhees, P. W. Ostwald Ripening and Relaxation in Dendritic Structures. Metall. Trans. A, 1984, 995-1001.Mendoza, R.; Savin, I.; Thornton, K.; Voorhees, P. W. Topological complexity and the dynamics of coarsening. Nat. Mater., 2004 385-388.Nelson, G. J.; Grew, K. N.; Izzo, J. R. Jr.; Lombardo, J. J.; Harris, W. M.; Faes, A.; Hessler-Wyser, A.; Van herle, J.; Wang, S.; Chu, Y. S.; Virkar, A. V.; Chiu, W. K. S. Three-dimensional microstructural changes in the Ni-YSZ solid oxide fuel cell anode during operation. Acta Mater., 2012 3491-3500. 7. Faes, A.; Hessler-Wyser, A.; Presvytes, D.; Vayenas, C. G.; Van herle, J. Nickel-Zirconia Anode Degradation and Triple Phase Boundary Quantification from Microstructural Analysis. Fuel Cells, 2009 841-851. Acknowledgements Financial support from the National Science Foundation (Award CBET-1134052) and an Energy Frontier Research Center on Science Based Nano-Structure Design and Synthesis of Heterogeneous Functional Materials for Energy Systems (HeteroFoaM Center) funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (Award DE-SC0001061) is gratefully acknowledged. X-ray nanotomography was performed with Dr. Steve Wang at the Advanced Photon Source supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357. Ni-YSZ samples were provided by MER Dr. J. Van herle (Ecole Polytechnique Federale de Lausanne, Switzerland).

Solid oxide fuel cells (SOFCs) are being extensively researched for clean power generation from coal-derived syngas. Some of the contaminants in syngas such as phosphine (PH3) may interact with the SOFC anode material, and degrade its electrochemical performance and material properties. In this paper, a modified Sagnac interferometry method is utilized to monitor the anode surface transient temperature as a function of applied current densities under hydrogen and simulated coal syngas. Moreover, the poisoning effects of PH3 contaminant on the SOFCs performance are investigated in dry and moist conditions. The experimental results indicate that the Ni-cermet-based SOFC anode is more susceptible to degradation due to PH3 in the presence of steam than under dry conditions. These experiments are valuable for the validation and the development of SOFC electrochemical models, and understanding the anode-contaminant interaction.

The effect that synthesis procedures have on the performance of (yttria-stabilized zirconia) anodes for solid oxide fuel cells (SOFC) has been investigated. Using a fixed concentration of 20 wt % Cu and 10 wt % impregnated into a porous YSZ matrix using metal salts, it is shown that the methods used to prepare and Cu have a large effect on the cell performance. Direct reduction of to Cu, without intermediate calcination to results in Cu films that have better electrical connectivity, but this does not enhance the final cell performance after exposure to n-butane. The calcination temperature for preparing from has a much more significant effect, with the area-specific resistance (ASR) of the anode in at 973 K increasing from 0.8 Ω cm2 at 723 K to >1.8 Ω cm2 at 1273 K and >2.6 Ω cm2 at 1523 K. X-ray diffraction results indicate that most of the ceria has not formed a solid solution, even at 1523 K. The cell performance is also affected by the solvent used for impregnation of Forming the film with in ethanol resulted in a cell with an anode ASR of ∼0.4 Ω cm2. Possible reasons for the strong dependence of the ceria film on cell performance are discussed. © 2003 The Electrochemical Society. All rights reserved.

Direct comparison between X-ray nanotomography and scanning electron microscopy for the microstructure characterization of a solid oxide fuel cell anode

Anodes composed of Ni-YSZ (yttria-stabilised zirconia) cermets are the key material to allow direct biofuel feeding to Solid Oxide Fuel Cell (SOFC) devices due to its internal reforming capability. The main challenge among these materials is related to carbon deposition poisoning effect when C-bearing fuels are feed. The work deals with these issues by alloying Ni with some metals like Cu to conform a multi-metallic anode material. Mechanical alloying (MA) at shaker mills is chosen as the route to incorporate the metal and ceramic powders in the anode material, also leading to better sintering behaviour. A projected cermet material is conceived where a third metal can be added based on two criteria: low Cu solubility and similar formation enthalpy of hydrides regarding Ni. Refractory metals like Nb, W and Mo, seems to fulfil these characteristics, as well as Ag. The MA resulted powder morphology is highly homogeneous showing nanometric interpolated metal lamellae. The sintering behaviour is investigated by conventional dilatometry as well as by stepwise isothermal dilatometry (SID) quasi-isothermal method to determine the sintering kinetic parameters. Based on these tools, it is found the Cu additive promotes sintering to obtain a denser anode and therefore allowing lower process temperatures. The consolidation is achieved through the sintering by activated surface (SAS) method allied to liquid phase sintering process, where the third metal additive also has influenced. The final cermet can be obtained at one sole process step, dispensing pore-forming additives and reduction treatments. The sintered microstructure demonstrates the material is homogeneous and possesses suitable percolation networks and pore structure for SOFC anode applications.

Characteristics of Ni/YSZ ceramic anode prepared using carbon microspheres as a pore former

Introduction For many potential mobile robot applications, current power supply technology (such as the lithium ion battery technology) is in fact a key limiting factor due to its low energy density. Solid oxide fuel cells (SOFCs) are a promising alternative and can overcome limitations of current battery technology. This is because SOFCs can, in principle, use not only hydrogen but also hydrocarbon fuels which have high energy density such as gasoline and so on.Ni-YSZ cermet is the most promising anode material for SOFCs because of its low cost, chemical stability, and closely matched thermalexpansion coefficients with the dense YSZ electrolyte. Ni is an excellent catalyst for hydrocarbon fuel reforming and cracking, which leads to rapid carbon deposition inside the SOFC anode and causes coking and deactivation1). In principle, the carbon deposition on Ni can be depressed by adding steam in the hydrocarbon fuel2,3), whereas few detailed investigations of SOFCs that operate on gasoline fuel have been reported.In this work, we studied the effect of steam content and demonstrated the direct operation of SOFCs by octane which is a main ingredient of gasoline. In the case of the Ni-YSZ anode, the operation temperature must be high in order to avoid sulfur poisoning4 -6 ), because most commercially available fuels contain sulfur. Therefore, in this study, the SOFCs operation was conducted at high temperature of 950 oC. Experimental Surface-polished YSZ pellets of 2 mm in thickness were used for the electrolyte. Pt cathode electrode and Pt reference electrode were prepared on the surface and side of the pellets, respectively, by firing Pt paste at 1300 oC. Then, NiO powder and GDC powder (NiO/YSZ=6/4 (wt)) were thoroughly mixed in a vacuum using the planetary ball mill (200 rpm, 12 h), and made into NiO-YSZ pastes using ethyl-cellulose and organic solvent. The NiO-YSZ paste was screen-printed in diameter of 8 mm on the YSZ pellets and sintered at 1200 oC for 1 h.Octane and steam were supplied to the SOFC cell by bubbling carrier gas (He) at a constant rate. Octane bubbler temperature was 30 oC, and Steam/Carbon ratio (S/C) were controlled by changing the temperature of the water bubbler from 40 to 70 oC. Electrochemical properties (open circuit voltage, anode electrode resistance, I - V and I - P characteristics, stable power generation property) were measured over a temperature range of 950-700 oC. During the constant current generation, exhaust gas was analyzed by gas chromatography. Results and Discussion Figure 1 shows I - V and I - P characteristics for the cells at 950 oC in wet octane. Maximum power density of 35 mW/cm2 was obtained by S/C of 8.9. The power density decreased with S/C quickly.Figure 2 shows the time course of cell voltage at a drawn current density of 5.2 mA/cm2 for S/C of 3.5. The cell voltage was stable. That is, carbon deposit does not arise even in the cell of the Ni-YSZ anode in low S/C of 3.5 when the operation temperature is high of 950 oC. References 1) S. Mclntosh and R.J. Gorte, “Direct Hydrocarbon Solid Oxide Fuel Cells,” Chemical Reviews, 104 (2004) 4845- 4865.2) K. Sasaki and Y. Teraoka, “Equilibria in Fuel Cell Gases: I. Equilibrium Compositions and Reforming Conditions,” Journal of Electrochemical Society, 850 (7) (2003) A878-A884.3) K. Sasaki and Y. Teraoka, “Equilibria in Fuel Cell Gases: II. The C-H-O Ternary Diagrams,” Journal of Electrochemical Society, 850 (7) (2003) A885-A888.4) K. Sasaki, K. Susuki, A. Iyoshi, M. Uchimura, N. Imamura, H. Kusaba, Y. Teraoka, H. Fuchino, K. Tsujimoto, Y. Uchida, N. Jingo, “H2S Poisoning of Solid Oxide Fuel Cells,” J. Electrochem. Soc., 153 (2006) A2023–A2029.5) P. Lohsoontorn, D.J.L. Brett, N.P. Brandon, “Thermodynamic predictions of the impact of fuel composition on the propensity of sulphur to interact with Ni and ceria-based anodes for solid oxide fuel cells,” Journal of Power Sources, 175 (2008) 60–67.6) H. Kishimoto, Y-P Xiong, K. Yamaji, T. Horita, N. Sakai, M.E. Brito, H. Yokokawa, “Stability of Ni base anode for direct hydrocarbon SOFCs, ” Journal Chemical Engineering of Japan, 40 (13) (2007) 1178-1182.

The electrochemical reduction of CO2 was studied via solid oxide electrolysis cell (SOEC), a type of device that can work reversely into a solid oxide fuel cell (SOFC) to generate electricity. Application of SOEC for CO2 electrolysis possesses potential rewards both in energy and environmental aspects, as it offers a way to recycle CO2 into chemicals and value-added fuels, which helps to reduce the accumulation of atmospheric CO2 and realize the carbon neutral cycling of fuels. Secondly, SOEC techniques provide a means to utilise the intermittent renewable sources, such as wind, tide, etc., as energy input to store excess electricity in the form of H2, CO and hydrocarbons and use these chemicals when necessary. Yet it is a challenging task to realize an efficient reduction of CO2 by SOEC due to the non-polar nature of CO2 fuels which are hard to be chemically absorbed and activated in high temperature range. The CO product from CO2 reduction is also demanding for the choice of fuel electrode (i.e. cathode in SOEC and anode in SOFC) materials, which has been an issue for the CO/hydrocarbon-fuelled SOFCs. To date, the CO2 electrolysis by SOEC is still at the starting point, and the mechanisms on the electrochemical reduction of CO2through SOECs are not fully understood. Extensive efforts need to be dedicated to the material developments, mechanism study, and system designs etc. Effort was made in our lab to find a highly performed, long-term durable cathode material for electrochemical reduction of CO2 by SOEC and to obtain more understandings of the mechanism of CO2 electrochemical reduction process. Different cathode materials were employed, including Ni-8 mol% yttria stabilised zirconia (YSZ) cermet, (La,Sr)(Cr,Mn)O3 (LSCM)-YSZ composite, and LSCM-(Gd, Ce)O2 (GDC) composite. Focus was casted on LSCM based cathodes which were found to be carbon-resistive, and the microstructure of LSCM-based cathodes was tuned to high performance and efficient CO2 electrolysis by the strategy of applying a gradient composite cathode and of adopting wet impregnation as cell fabrication procedures. The electrochemical performance of CO2 electrolysis was characterized in various CO2-CO mixtures and applied potentials in 900-750oC with the aid of impedance spectroscopy, on YSZ electrolyte supported three-electrode SOECs. In this paper, impedance behaviour of the electrochemical reduction reaction of CO2 from different cathode SOECs was correlated with the variations in gas composition, operating temperature and loading potential. As both charge transfer and surface adsorption/desorption equilibration and surface diffusion of activated species were found to be dominant processes taking place in the scope of cathodes under examination, with the later being significant in CO2-rich fuels, areas of discussion will be the effects of operational conditions on the impedance arcs associated with these steps, and how the cathode microstructure impacts the impedance behaviour and the corresponding elementary steps from CO2electrochemical reduction. By introducing a LSCM-YSZ 30-70/LSCM-YSZ 60-40 graded cathode and by incorporating extra catalyst into LSCM-GDC composite, the cathode performance was greatly improved, and the surface activity was profoundly accelerated. However, the most effective way to promote cathode performance was to introduce the cathode components in separate steps via wet impregnation. A competitive CO2 electrolysis performance to Ni-YSZ cermet was obtained from the GDC impregnated LSCM-YSZ cathode with 0.5% Pd extra catalyst, which also showed a comparable performance between SOEC and SOFC when operating in CO2-CO 50-50 mixture.

Solid Oxide Fuel Cells (SOFCs) operate under harsh environments, which cause the deterioration of anode material properties and reduce their service life. In addition to electrochemical performance, structural integrity of the SOFC anode is essential for successful long-term operation. Anode-supported SOFCs rely on the anode to provide mechanical strength to the positive-electrolyte-negative (PEN) structure. The stress field in the anode may arise from a variety of phenomena including thermal expansion mismatch between layers in the PEN structure, thermal/redox cycles and external mechanical loads. Moreover, some fuel contaminants such as phosphine (PH3) interact with the anode materials which lead to the formation of secondary phases and grain growth. These mechanisms result in the formation of microcracks, and degrade anode structural and electrochemical properties. Assessments of the evolution of anode mechanical properties during long-term operation are therefore essential to predict SOFC working life.;The principal objective of this research is to develop a structural durability model for the SOFC anode that takes into account thermo-mechanical and fuel contaminants effects on the anode material properties. The model is implemented in finite element analysis through a user defined subroutine to predict anode long-term structural integrity. The model is exploited to predict the stress-strain relations of Ni-YSZ at temperatures and porosities which are difficult to generate experimentally. Accelerated exposure tests under high contaminant concentrations dictate that the electrochemical degradation is the principal mode of cell failure while the cell structure is still intact. However, the model predicts that under lower contaminant concentrations, the anode structural degradation may be significant as compared to the electrochemical degradation in long-term operation.;The proposed model is enhanced for the planar-SOFC configurations exposed to PH3. The model predicts that under pure thermo-mechanical effect, the critical location for structure failure is near the corner of highest thermal gradient. However when fuel contaminant structural effect is superimposed on the thermo-mechanical effect, the critical location may shift depending on the flow configuration. Under similar operating conditions, i.e. same current density, co-flow configuration yields a higher anode structural life than counter-flow or cross-flow configurations. The knowledge obtained from this research will be useful to establish control parameters to achieve desired service life of the SOFC stack under various operating conditions.

Solid Oxide Fuel Cells (SOFCs) are an interesting energy conversion device due to their fuel flexibility feature and high fuel conversion efficiency. Reducing the performance losses associated with fuel electrode is critical, especially when SOFCs are operated on hydrocarbon fuels. The fuel electrode in an SOFC has typically been a cermet of Ni-YSZ whose degradation mechanisms have been thoroughly studied. Recently, the focus of SOFC research has shifted towards a lower operating temperature range (400-650 oC) to achieve reliability and cost competitiveness among other energy conversion technologies. The use of a Ni-GDC cermet anode allows SOFCs to operate on hydrocarbon fuels at lower temperatures compared to (>800 oC) for Ni-YSZ. However, Ni-based anodes have several challenges that have to be resolved for efficient operation of SOFCs. Evaluating the microstructural changes such as coarsening and carbon formation when exposed to hydrocarbon fuels is essential to understand the underlying degradation mechanism and to overcome the issues. This study focuses on a) evaluating the chemical compatibility of Ni-GDC cermet anode when exposed to harsh operating conditions and b) to propose a possible degradation mechanism at low temperature ranges by carefully examining the microstructural changes on samples that are aged in hydrocarbon containing fuels.

Two perovskite materials with SrMo1−xAlxO3−δ (x = 0.1, 0.2) compositions have been synthesized by reduction from the corresponding scheelite phases, with SrMo1−xAlxO4−δ stoichiometry; the pertinent characterization shows that the defective perovskites can be used as anode materials in solid oxide fuel cells, providing maximum output power densities of 633 mW/cm2 for x = 0.2. To correlate structure and properties, a neutron powder diffraction investigation was carried out for both perovskite and scheelite phases. Both perovskites are cubic, defined in the Pm-3m space group, displaying a random distribution of Mo and Al cations over the 1a sites of the structure. The introduction of Al at Mo positions produced conspicuous amounts of oxygen vacancies in the perovskite, detected by neutrons. This is essential to induce ionic diffusion, providing a mixed ionic and electronic conduction (MIEC), since in MIEC electrodes, charge carriers are combined in one single phase and the ionic conductivity can be one order of magnitude higher than in a conventional material. The thermal expansion coefficients of the reduced and oxidized samples demonstrated that these materials perfectly match with the La0.8Sr0.2Ga0.83Mg0.17O3−δ electrolyte, La0.4Ce0.6O2−δ buffer layer and other components of the cell. Scanning electron microscopy after the test in a real solid oxide fuel cell showed a very dense electrolyte and porous electrodes, essential requirements for this type of fuel. SrMo1−xAlxO3−δ perovskites are, thus, a good replacement of conventional biphasic cermet anodes in solid oxide fuel cells.

Assessment of a methanol-fueled integrated hybrid power system of solid oxide fuel cell and low-speed two-stroke engine for maritime application

High material and production costs are key barriers to the widespread commercialization of solid oxide fuel cells (SOFCs). Thermal spray techniques are a low cost alternative for the production of SOFCs. The objective of this work was to fabricate single cells by thermal spraying and to evaluate the impact of electrolytes and anodes, differing in terms of thickness, composition and microstructure, on the cell performance. In this work, the anode layer was deposited on a planar ferritic steel support with in-plane dimensions 50 mm X 50 mm, thickness of 550 µm and 35-40% porosity by atmospheric plasma spraying (APS). The anode material consisted of nickel, yttria stabilized zirconia (YSZ) and a pore former. The anode layer thickness was around 60 µm. The electrolyte layer was deposited by a low pressure plasma spray technique called plasma spray-thin film (PS-TF) which can produce dense coatings at high deposition rates. The electrolyte material consisted of 3YSZ and 8YSZ consisting of different powder morphologies such as fused and crushed and agglomerated and sintered. In order to ensure sufficient gas tightness, electrolytes thicknesses of 50-90 µm were deposited. The cathode layer was screen-printed and sintered in-situ during the start-up of the electrochemical tests. The cathode material was La0.58Sr0.4Co0.2Fe0.8O3-δ (LSCF). It must be noted that no diffusion barrier layer was deposited between the YSZ electrolyte and the LSCF cathode which will affect the performance and stability of the cells. The electrochemical tests were performed in a temperature range of 600-800°C at atmospheric pressure under various gas compositions of H2, H2O and N2 on the anode side and of O2 and N2 on the cathode side while keeping the total gas flow constant. Current-voltage characteristics and impedance spectra were measured. Porous anodes and dense electrolytes were achieved in all cases. The measured open cell voltage indicated acceptable electrolyte gas tightness. Power density of produced cells at an operating voltage of 0.7 V were measured as high as 600 mW/cm2. In this work, the impact of spray parameters and applied layer thicknesses on the gas tightness of the electrolyte and the area specific resistance of the cell will be discussed. Keywords: plasma spraying, solid oxide fuel cells, electrochemical characterization, impedance spectroscopy