A amônia presente em galpões fechados de criação de frangos afeta a saúde tanto dos animais como dos tratadores, além de ser um grave problema ambiental. O processo aqui recomendado faz uso de um material com grande capacidade de retenção tanto da amônia gasosa como na forma de seu hidróxido, NH4OH. Este absorvedor, um trocador catiônico sólido, preparado para a retenção seletiva da amônia, é inodoro, insípido e atóxico. Uma vez saturado com amônia, passa por um tratamento químico para a remoção deste composto, podendo ser reutilizado muitas vezes sem perda de sua capacidade retentora, tornando o processo mais econômico. A remoção deste material pode-se dar na forma de um sal de amônio que poderá ser utilizado como fertilizante. Ressalta-se ainda que a amônia recuperada nestes galpões avícolas, quando submetida a uma decomposição térmica catalítica, gera hidrogênio para uso em células a combustível, podendo fornecer energia elétrica no próprio local do trabalho. / The process here stressed uses a cátion exchange material. The aim of the present work has been to prepare a suitable cation exchanger material with excepecinally high selectivity for ammonia, as the cation NH4+ or as aqueous ammonia solution containing NH4OH hyroxide as well. Aliquots of the abovementioned exchangers were set up inside an chiken farm production near São Paulo city. Periodically the exchanger was removed to the laboratory and eluted with a convenient acid to regenerate the exchanger for the new cicle. The ammonia retention was quite high and presents no dificulty for its elution. The selected exchanger is a solid material, non toxic, without smell and have good physical properties. The first results encouraged us and our plants to do large experiments that in progress. This process is a contribution to remediation of the avicola local, removing the ammonia gas and suppressing grettly its smell and bad effect to the animals and even to workers

Células a combustível de óxido sólido são sistemas capazes de gerar energia elétrica por meio da oxidação de moléculas hidrogenadas. Normalmente os sistemas planares e tubulares, são compostos por quatro constituintes bem definidos: cátodo, ânodo, eletrólito e selante. Este último componente é o foco do presente estudo, sendo que suas principais características são estabilidade química na temperatura de operação da célula, isolamento elétrico e coeficiente de expansão térmica compatível com os outros constituintes, além da viscosidade elevada e resistência química em atmosferas oxidantes e redutoras. Devido à geometria planar e de multicamadas da célula se optou por usar como selante vidros niobofosfatos. A selagem foi realizada a partir de dispersão de pó de vidro em álcool etílico, gerando uma solução viscosa que foi aplicada sobre o substrato. Posteriormente realizou se um tratamento térmico para a consolidação do selamento. Os vidros estudados foram denominados de Nb30, Nb37, Nb40 e Nb44, de acordo com o teor nominal de óxido de nióbio utilizado na composição. O objetivo desse trabalho foi caracterizar, a partir de precursores os selantes a base de vidros niobofosfatos para aplicar em células a combustível de óxido sólido do tipo planar. Foram feitos caracterizações dos pós dos vidros e de pastilhas cristalizadas para determinar os coeficientes de expansão térmica (CET), resistividade elétrica, difração de raio X e microscopia eletrônica de varredura (MEV), além de, caracterizar visualmente sua adesividade, molhabilidade, resistência mecânica em substratos de alumina e em conjunto com os componentes das SOFC, sendo também testados os selantes em operação nas unidades previamente formadas de SOFC (ciclos térmicos). / Solid oxide fuel cells (SOFC) are devices which generate d.c. power by the oxidation of hydrogen molecules. These devices can have a multilayer plane design containing a cathode, an anode, a solid electrolyte, and a sealing material. The sealing, which is the subject of this study, has to be chemically stable at relatively SOFC operational condition in oxi-redox atmospheres, electrical insulator, with a thermal expansion coefficient matching other components, and, in of glass, the viscosity must be relatively high. The aim of the present work is to characterize niobophosphate glasses which will be used as sealant precursors of Solid Oxide Fuel Cell with a plane design. Niobophosphate glasses, named Nb30, Nb37, Nb40, and Nb44 according to the niobium content, were investigated for this purpose. The sealing was performed by mixing glass powder with ethanol which was applied over the substrate. Later, a heat treatment was performed to consolidate the sealing. Glass powder and devitrified glass pellets were characterized by different techniques. The thermal expansion coefficient, electrical resistivity, and the X-rays diffraction pattern were determined for these materials. Scanning electron microscopy was also used to visualize the sealing/ substrate interface, and to evaluate the adhesiveness, wetability, apparent mechanical resistance in alumina substrates and in other SOFC components. The sealants were tested in SOFC, and also submitted to simulating thermal cycles.

Os problemas ambientais originados pela produção e consumo das tradicionais fontes de energia pressionam a sociedade pelo desenvolvimento e utilização de fontes de energia limpas e renováveis. Dentre as novas tecnologias, células a combustível de membrana de troca protônica (PEMFC) apresentam-se como uma alternativa viável, aliando elevadas taxas de conversão energética a níveis mínimos de poluentes gerados. No entanto, a utilização plena desses dispositivos depende de fatores como desempenho, estabilidade e custo dos mesmos. Um dos principais elementos que afeta o desempenho de uma PEMFC é a eficiência com o qual o oxigênio é reduzido no cátodo. Assim, diversos estudos visando a obtenção de eletrocatalisadores à base de Pt que apresentem bom desempenho frente à reação de redução de oxigênio (RRO) e elevada estabilidade têm sido desenvolvidos, recebendo destaque os catalisadores Pt-Y. Neste trabalho catalisadores Pt-Y, com diferentes proporções entre os metais, suportados em carbono de alta área superficial foram sintetizados através de uma modificação no método do ácido fórmico. Os materiais foram caracterizados através das técnicas de EDX, XRD, TEM e XPS, e avaliados frente à RRO através de medidas em meia célula, empregando-se a técnica de eletrodo de disco rotatório, e em célula unitária, como cátodo de PEMFC. O catalisador Pt-Y/C 7:3 foi o que apresentou melhor desempenho dentre os materiais bimetálicos. Através dos testes de envelhecimento acelerado (TEA) constatou-se que, além da degradação das nanopartículas de platina, o ítrio passa por dissolução. / The environmental impacts generated by the production and consumption of traditional energy sources leads society to develop clean and renewable energy sources. Among the new technology, proton exchange membrane fuel cells (PEMFC) appear as viable alternative, allying high energy conversion rates to minimum levels of pollutants generated. However, the full utilization of these devices depends on factors such as its performance, stability and cost. One of the major elements that affect the PEMFC performance is the cathode performance. Thus, several studies aiming at obtaining Pt based electrocatalysts with good performance for oxygen reduction reaction (ORR) and high stability have been developed, receiving attention the Pt-Y catalysts. In this work Pt-Y catalysts, supported on high surface area carbon, were synthesized through a modification on formic acid method. The materials were characterized using EDX, XDR, TEM and XPS, and evaluated towards ORR through measurements in half cell, using rotating disk electrode technique, and in unit cell, as cathode of PEMFC. The catalyst Pt-Y/C 7:3 had the best performance among the bimetallic materials. Through accelerated aging tests (AGT), in addition to platinum nanoparticles degradation, yttrium dissolution was also observed.

Photosynthetic Microbial Fuel Cell (p-MFC) research aims to develop devices containing photosynthetic micro-organisms to produce electricity. Micro-organisms within the device photosynthesise carbohydrates under illumination, and produce reductive equivalents (excess electrons) from both carbohydrate production and the subsequent carbohydrate break down. Redox mediators are utilised to shuttle electrons between the organism and the electrode. The mediator is reduced by the micro-organism and subsequently re-oxidised at the electrode. However this technology is in its early stages and extensive research is required for p-MFC devices to become economically viable. A basic p-MFC device containing a potassium ferricyanide mediator and the algae Chlorella vulgaris was assembled and tested. From these initial experiments it was realised that much more work was required to characterise cell and redox mediator activities occurring within the device. There is very little p-MFC literature dealing with cellular interaction with redox mediators, but without this knowledge the output of complete p-MFC devices can not be fully understood. This thesis presents research into the reduction of redox mediators by the micro-organisms, including rates of mediator reduction and factors affecting the rate. Both electrochemical and non-electrochemical techniques are used and results compared. Additionally, cellular effects relating to the presence of the mediator are studied; crucial to provide limits within which p-MFCs must be used. After basic characterisation, this thesis presents work into the optimisation of the basic p-MFC. Different redox mediators, photosynthetic species and anodic materials are investigated. Importantly, it is only through fundamental characterization to improve understanding that p-MFCs can be optimised.

The search for environmentally benign energy sources is becoming increasingly urgent. One such technology is fuel cells, e.g., the polymer electrolyte membrane (PEM) fuel cell which uses hydrogen as a fuel and emits only H2O. However, reforming hydrocarbon fuels to produce the needed hydrogen yields reformate streams containing CO2 as well as CO, which is toxic to the PEM fuel cell at concentrations above 100ppm. As the amount of CO permitted to reach the fuel cell increases, the performance of the PEM fuel cell decreases until it ultimately stops functioning. The water-gas-shift (WGS) reaction, CO + H2O <-> H2 + CO2, provides a method for extracting the energy from the toxic CO by converting it into usable H2 along with CO2 which can be tolerated by the fuel cell. Although a well established industrial process, alternate catalysts are sought for fuel cell application. Catalyst selection for the WGS reaction has, until recently, been based on trial-and-error screening of potential catalysts due to a lack of fundamental understanding of the catalyst's functioning. For this reason, we embarked on a deeper understanding of the molecular events involved in the WGS reaction such that a more systematic and theory-guided approach may be used to design and select catalysts more efficiently, i.e., rational catalyst design. The goal of this research was to develop a comprehensive predictive microkinetic model for the WGS reaction which is based solely on a detailed mechanism as well as theories of surface-molecule interactions (i.e., the transition-state theory) with energetic parameters determined a priori. This was followed by a comparison of the experimental results of sample catalysts to validate the model for various metal-based catalysts of interest including Cu, Fe, Ni, Pd, Pt, Rh, and Ru. A comprehensive mechanism of the plausible elementary reaction steps was compiled from existing mechanisms in the literature. These were supplemented with other likely candidates which are derivatives of those identified in the literature. Using established theories, we predicted the kinetics of each of the elementary reaction steps on metal catalysts of interest. The Unity Bond Index-Quadratic Exponential Potential Method (UBI-QEP) was used to predict the activation energies in both the forward and reverse direction of each step based solely on heats of chemisorption and bond dissociation energies of the species involved. The Transition State Theory (TST) was used to predict the pre-exponential factors for each step assuming an immobile transition state; however, the pre-exponential factors were adjusted slightly to ensure thermodynamic consistency with the overall WGS reaction. In addition, we have developed a new and powerful theoretical tool to gain further insight into the dominant pathways on a catalytic surface as reactants become products. Reaction Route (RR) Graph Theory incorporates fundamental elements of graph theory and electrical network theory to graphically depict and analyze reaction mechanisms. The stoichiometry of a mechanism determines the connectivity of the elementary reaction steps. Each elementary reaction step is viewed as a single branch with an assumed direction corresponding to the assumed forward direction of the elementary reaction step. The steps become interconnected via nodes which reflect the quasi-steady state conditions of the species represented by the node. A complete RR graph intertwines a series of routes by which the reactants may be converted to products. Once constructed, the RR graph may be converted into an electrical network by replacing, in the steady-state case, each elementary reaction step branch with a resistor and including the overall reaction as a power source where rate and affinity correspond to current and voltage, respectively. A simplification and reduction of the mechanism may be performed based on results from a rigorous De Donder affinity analysis as it correlates to Kirchhoff's Voltage Law (KVL), akin to thermodynamic consistency, coupled with quasi-steady state conditions, i.e., conservation of mass, analyzed using Kirchhoff's Current Law (KCL). Hence, given the elementary reaction step resistances, in conjunction with Kirchhoff's Laws, a systematic reduction of the network identifies the dominant routes, e.g., the routes with the lowest resistance, along with slow and quasi-equilibrium elementary reaction steps, yielding a simplified mechanism from which a predictive rate expression may possibly be derived. Here, we have applied RR Graph Theory to the WGS reaction. An 18-step mechanism was employed to understand and predict the kinetics of the WGS reaction. From the stoichiometric matrix for this mechanism, the topological features necessary to assemble the RR graph, namely the intermediate nodes, terminal nodes, empty reaction routes and full reaction routes, were enumerated and the graph constructed. The assembly of the RR graph provides a comprehensive overview of the mechanism. After reduction of the network, the simplified mechanism, comprising the dominant pathways, identified the quasi-equilibrium and rate-determining steps, which were used to determine the simplified rate expression which predicts the rate of the complete mechanism for different catalysts. Experimental investigations were conducted on the catalysts of interest to validate the microkinetic model derived. Comparison of the experimental results from the industrially employed catalysts (e.g., Cu, Ni, Fe, etc.) shows that the simplified microkinetic model sufficiently predicts the behavior of the WGS reaction for this series of catalysts with very good agreement. Other catalysis tested (Pt, Pd, Rh and Ru), however, had sufficient methanation activity that a direct comparison with WGS kinetics could not be made. In summary, we have developed a comprehensive approach to unravel the mechanism and kinetics of a catalytic reaction. The methodology described provides a more fundamental depiction of events on the surface of a catalyst paving the way for rational analysis and catalyst design. Illustrated here with the WGS reaction as an example, we show that the dominant RRs may be systematically determined through the application of rigorous fundamental constraints (e.g. thermodynamic consistency and mass conservation) yielding a corresponding explicit a priori rate expression which illustrates very good agreement not only with the complete microkinetic mechanism, but also the experimental data. Overall, RR graph theory is a powerful new tool that may become invaluable for unraveling the mechanism and kinetics of complex catalytic reactions via a common-sense approach based on fundamentals.

Proton exchange membrane (PEM) fuel cells are at the forefront among different types of fuel cells and are likely to be important power sources in the near future. PEM is a key component of the PEM fuel cells. The objective of this research is to investigate the fundamental aspects of PEM in terms of thermodynamics and proton transport in the membrane, so that the new proton conducting materials may be developed based on the detailed understanding. Since the proton conductivity increases dramatically with the amount of water in PEM, it is important to maintain a high humidification during the fuel cell operation. Therefore, the water uptake characteristics of the membrane are very important in developing fuel cell systems. Thermodynamic models are developed to describe sorption in proton-exchange membranes (PEMs), which can predict the complete isotherm as well as provide a plausible explanation for the long unresolved phenomenon termed Schroeder¡¯s paradox, namely the difference between the amounts sorbed from a liquid solvent versus from its saturated vapor. The sorption isotherm is a result of equilibrium established in the polymer-solvent system when the swelling pressure due to the uptake of solvent is balanced by the surface and elastic deformation pressures that restrain further stretching of the polymer network. The transport of protons in PEMs is intriguing. It requires knowledge of the PEM structure, water sorption thermodynamics in PEM, proton distribution in PEM, interactions between the protons and PEM, and proton transport in aqueous solution. Even proton conduction in water is anomalous that has received considerable attention for over a century because of its paramount importance in chemical, biological, and electrochemical systems. A pore transport model is proposed to describe proton diffusion at various hydration levels within Nafion¢ÃƒÂ§ by incorporating structural effect upon water uptake and various proton transport mechanisms, namely proton hopping on pore surface, Grotthuss diffusion in pore bulk, and ordinary mass diffusion of hydronium ions. A comprehensive random walk basis that relates the molecular details of proton transfer to the continuum diffusion coefficients has been applied to provide the transport details in the molecular scale within the pores of PEM. The proton conductivity in contact with water vapor is accurately predicted as a function of relative humidity without any fitted parameters. This theoretical model is quite insightful and provides design variables for developing high proton conducting PEMs. The proton transport model has been extended to the nanocomposite membranes being designed for higher temperature operation which are prepared via modification of polymer (host membrane) by the incorporation of inorganics such as SiO2 and ZrO2. The operation of fuel cells at high temperature provides many advantages, especially for CO poisoning. A proton transport model is proposed to describe proton diffusion in nanocomposite Nafion¢ÃƒÂ§/(ZrO2/SO42-) membranes. This model adequately accounts for the acidity, surface acid density, particle size, and the amount of loading of the inorganics. The higher proton conductivity of the composite membrane compared with that of Nafion is observed experimentally and also predicted by the model. Finally, some applications of PEM fuel cells are considered including direct methanol fuel cells, palladium barrier anode, and water electrolysis in regenerative fuel cells.

Proton-Exchange Membrane (PEM) fuel cells are extremely attractive for replacing internal combustion engines in the next generation of automobiles. However, two major technical challenges remain to be resolved before PEM fuel cells become commercially successful. The first issue is that CO, produced in trace amounts in fuel reformer, severely limits the performance of the conventional platinum-based PEM fuel cell. A possible solution to the CO poisoning is higher temperature operation, as the CO adsorption and oxidation overpotential decrease considerably with increasing temperature. However, the process temperature is limited in atmospheric fuel cells because water is critical for high conductivity in the standard PEM. An increase in operating pressure allows higher temperature operation, although at the expense of parasitic power for the compressor. Further the conventional PEM, Nafion? is limited to 120°C due to it's low glass transition temperature. Thus, the design of higher temperature PEMs with stable performance under low relative humidity (RH) conditions is considered based on a proton transport model for the PEM and a fuel cell model that have been developed. These predictive models capture the significant aspects of the experimental results with a minimum number of fitted parameters and provides insight into the design of higher temperature PEMs operating at low RH. The design of an efficacious high temperature, low RH, PEM was based on enhancing the acidity and water sorption properties of a conventional PEM by impregnating it with a solid superacid. A systematic investigation of the composite Nafion?inorganic PEMs comprising experiments involving water uptake, ion-exchange capacity (IEC), conductivity and fuel cell polarization is presented in the work. The most promising composite is the nano-structured ZrO2/Nafion?PEM which exhibits an increase in the IEC, a 40% increase in water sorbed and a resulting 24% conductivity enhancement vs. unmodified Nafion?112 at 120°C and at RH < 40%.

Metallic interconnects in intermediate temperature solid oxide fuel cells (IT-SOFC) stacks form Cr2O3 scales on their surface. Such oxide scales can be further oxidized to Cr6+ containing gaseous species that migrate and deposit at the cathode triple phase boundaries, causing significant degradation in the performance of the SOFCs. This phenomenon is termed as ‘Cr-poisoning’. A solution to this problem is the application of coatings on the interconnects that act as a diffusion barrier to Cr migration. Two different Cu/Mn spinel compositions, Cu1.3Mn1.7O4 and CuMn1.8O4, were studied as coating materials. Dense coatings were deposited on both flat plates and meshes by electrophoretic deposition (EPD) followed by subsequent thermo-mechanical or thermal densification steps. At room temperature, Cu1.3Mn1.7O4 coatings were found to have a mixture of CuO and spinel phases, while CuMn1.8O4 coatings were found to have a mixture of Mn3O4 and spinel phases. However, CuMn1.8O4 is a pure spinel phase between 750 °C and 850 °C. After densification processing and high temperature oxidation, a Cr2O3 layer was formed at the coating/alloy interface, which partially reacted with the spinel coatings to form a dense cubic spinel layer of the general composition (Cu,Mn,Cr)3-xO4. In addition, Cr-rich precipitates, formed in the dense layer close to coating/alloy interface. It is believed that these are Cr2O3 precipitates, formed when the solubility of Cr in the spinel phase is reached. Solubility experiments using powders showed that 1 mole of CuMn1.8O4 can effectively getter 1.83 moles of Cr2O3 at 800°C. Electrical conductivity of (Cu,Mn,Cr)3-xO4 was found to be at least two orders of magnitude higher than that of Cr2O3. The coatings acted as an effective Cr getter whose lifetime depends on the oxidation temperature, coating thickness, and the overall porosity in the coating. In-cell electrochemical testing showed that the CuMn1.8O4 coatings on Crofer 22 APU meshes performed significantly better than commercial Cu/Mn spinel coatings. The CuMn1.8O4 coatings gettered Cr effectively for 12 days at 800 ºC, leading to no performance loss of the cell due to Cr-poisoning. Significantly longer lifetime can be achieved at 750 ºC or lower, which is the target operational temperature regime of IT-SOFCs.

Made available in DSpace on 2017-07-21T20:43:51Z (GMT). No. of bitstreams: 1 Tufy Kabbas Junior.pdf: 2988725 bytes, checksum: bd676d57a21df0604e836ad177676653 (MD5) Previous issue date: 2017-01-27 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / Due to the need for clean energy, an alternative that has gained worldwide prominence are like fuel cells. As proton conductive ceramics have an operating temperature in the range of 600 to 800 ° C, making them especially interesting for a fuel cell manufacturing. In this way, the objective of this work was to study a peroxide production with mixed proton-electronic conductivity to update as cell cathodes a solid oxide fuel with proton conductivity. These composites are produced using the mechanical mixture from a quality database, which has electronic conductivity in the proportions 25/75, 50/50 and 75/25, sintered at 1400 ° C. The composite 25 / 75 and 75/25 showed to be only of an electronic and ionic conductor (oxygen ions), respectively, showing no mixed-protonic conductivity. The 50/50 composite, through the obtained results, leads to believe that the mixed proton-electronic conductivity occurred. / Devido à necessidade de se produzir energia limpa, uma alternativa que tem ganho destaque mundial são as células a combustível. As cerâmicas condutoras protônicas possuem uma temperatura de operação na faixa de 600 a 800ºC, tornando-as especialmente interessantes para a fabricação de células a combustível. Desta forma, este trabalho teve por objetivo estudar a obtenção de perovisquitas com condutividade mista protônica-eletrônica para atuar como cátodos de células a combustível de óxido sólido com condutividade protônica. Estes compósitos foram produzidos utilizando-se mistura mecânica, da perovisquita BaCe0,2Zr0,7Y0,1O3-d (BCZY), a qual possui condutividade protônica, com a perovisquita LaNi0,5Cr0,5O3 (LNC), que possui condutividade eletrônica, nas proporções 25/75, 50/50 e 75/25, sinterizadas à 1400°C. Os compósitos 25/75 e 75/25 demonstraram ser apenas de um condutor eletrônico e iônico (íons oxigênio) respectivamente, não mostrando condutividade mista eletrônica-protônica. Já o compósito 50/50, através dos resultados obtidos através de mapeamento químico e espectroscopia de impedância, demonstram um provável aparecimento de condutividade mista protônica-eletrônica.

Neste trabalho, investigou-se a obtenção de fibras de La0,6Sr0,4Co1-yFeyO3 pela técnica de electrospinning e sua caracterização visando a sua aplicação como cátodo em células a combustível de óxido sólido de temperatura intermediária (SOFC-IT). Foram obtidos 5 compostos perovskitas LaxSr1-xCo1-yFeyO3 (LSCF) variando-se a quantidade de cobalto na composição (La0,6Sr0,4Co1-yFeyO3, sendo y = 1,0; 0,8; 0,6; 0,4; 0,2). As fibras LSCF, após tratamento térmico de 1000 ºC, apresentaram diâmetro médio em torno de 1 μm e estrutura perovskita com simetria romboédrica, com exceção do composto La0,6Sr0,4FeO3, que apresentou estrutura ortorrômbica. Foram avaliadas as propriedades elétricas das fibras sem compactação, compactada e sinterizada no intervalo de temperatura de 25-900 ºC. A condutividade elétrica das fibras LSCF aumentou com a compactação e sinterização das fibras e com o aumento do conteúdo de cobalto. As fibras sem compactação apresentaram valores de condutividade elétrica entre 0,23 S.cm-1 para La0,6Sr0,4FeO3 (LSF) à 0,43 S.cm-1 para La0,6Sr0,4Co0,8Fe0,2O3 (LSCF82) a 600 °C. Nas fibras compactadas os valores de condutividade elétrica aumentaram de 0,90 S.cm-1 para LSF à 9,06 S.cm-1 para LSCF82 a 600 °C. As fibras sinterizadas apresentaram os maiores valores de condutividade elétrica, 71 S.cm-1 para LSF e 832 S.cm-1 para LSCF82 em 600 ºC. A avaliação do desempenho eletroquímico das fibras LSCF como cátodo foi estudada por espectroscopia de impedância em células simétricas, contendo o eletrólito de céria dopada com gadolínio (CGO) e cátodos LSCF infiltrados com CGO. As medidas de impedância mostraram que os diagramas de Nyquist são compostos de dois a três semicírculos, dependendo da temperatura da medida. Os cátodos LSCF com maior conteúdo de cobalto apresentaram menor resistência de polarização. O cátodo La0,6Sr0,4Co0,8Fe0,2O3 apresentou a menor resistência de polarização entre 500 e 900 °C, classificando este cátodo compósito como um promissor material para SOFC de temperatura intermediária baseado em eletrólito CGO. / In this work, the preparation of La0.6Sr0.4Co1-yFeyO3 fibers by electrospinning and its characterization was investigated aiming the production of cathodes for Intermediate Temperature Solid Oxide Fuel Cell (SOFC-IT). Five compounds of the family LaxSr1-xCo1-yFeyO3 (LSCF) were obtained varying the cobalt content (La0.6Sr0.4Co1-yFeyO3, where y = 1.0; 0.8; 0.6; 0.4; 0.2). The electrospun La0.6Sr0.4Co1-yFeyO3 (y=0.2-1.0) fibers resulted in an average diameter of about 1 μm and perovskite crystalline structure with rhombohedral symmetry after heat treatment at 1000 °C, except for La0.6Sr0.4FeO3 that crystallized in an orthorhombic structure. The electrical properties of the fibers in the non-compacted, compacted and sintered forms were investigated in the temperature range of 25-900 °C. The electrical conductivity of LSCF fibers increases with the compaction and sintering of the fibers and with the increase of cobalt content. The non-compacted fibers showed electrical conductivities ranging from 0.23 S.cm-1 for La0.6Sr0.4FeO3 (LSF) up to 0.43 S.cm-1 for La0.6Sr0.4Co0.8Fe0.2O3 (LSCF82) at 600 °C. The electrical conductivity increased in compacted fiber samples to 0.90 S.cm-1 for LSF and to 9.06 S.cm-1 for LSCF82 at 600 °C. The sintered fibers showed the highest electrical conductivity for all samples, 71 S.cm-1 for LSF and 832 S.cm-1 for LSCF82 at 600 ºC. The electrochemical performance of LSCF fibers as cathode was studied by impedance spectroscopy in symmetrical cells containing gadolinium doped ceria (CGO) electrolyte and LSCF cathode infiltrated with CGO. Impedance measurements showed that the Nyquist diagrams have two or three semicircles, depending on the measurement temperature. The LSCF cathodes with higher cobalt content exhibit lower polarization resistance and the La0.6Sr0.4Co0.8Fe0.2O3 cathode had the lowest polarization resistance between 500 and 900 °C, classifying this composite cathode as a promising material for intermediate temperature SOFC based on CGO electrolyte.