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As foodstuffs are being produced, transported and stored in greater quantities than ever before in human history and with an alarming amount of food products being lost to spoilage every year, new, environmentally friendly ways of preserving food products are being actively researched and developed in today’s world. Oxygen is a key pathway towards food decay and destruction, due to its dual roles as a source of respiration for the multitude of microorganisms that can cause food spoilage and through direct destruction through oxidation reactions within food products that cause oxidative deterioration. Fuel cells have the theoretical potential to be an energy efficient and environmentally friendly way of preserving food, such as fish, fruit and vegetables.  Because of their nature to consume oxygen through the electrochemical reactions that produces their electrical power, they have the potential to be used to reduce localised oxygen content for the storage and transportation of foods, minimising their spoilage, as well as potentially providing electrical energy for other components in potential control systems for the fuel cell. The purpose of this project is to design and build a PEM fuel cell and examine its potential for lowering of oxygen concentrations at the gas output at the cathode.  The outcome of these experiments are designed to validate the  theoretical capacity of fuel cells to reduce output oxygen concentrations to levels that are able to aid in the preservation of foodstuffs.  It is hoped that this study, in conjunction with the researched literature, can be used as a guide for future food shipping and storage methods. The experimental stage of this diploma work was unsatisfactory. The fuel cell was unable to produce a voltage and the reactant gases were unable to flow through the fuel cell due to a design flaw. Therefore the effectiveness of a fuel cell for depletion of oxygen to levels able to preserve food is based on the theoretical basis of the internal PEM fuel cell reactions, as well as studying past literature and patents. If the theoretical ability of the fuel cell is proven, it can be asserted that PEM fuel cells have the potential to be a real contender in the field of food preservation in shipping and storage, as well as offering greater levels of control for supplies for how and when they can ship their product. However this will require more independent research development work on the effects of low oxygen concentrations on a fuel cell operation as well as the preservation effects on a greater variety of foodstuffs. Furthermore, more research is required for more efficient and cheaper fuel cell catalysts or innovative designs are required to avoid concentration losses that arise from oxygen reduction at low oxygen levels.

[ES] Las pilas de combustibles son dispositivos de un coste elevado y frágiles ante ambientes contaminados o condiciones inadecuadas de operación como: temperaturas extremas o mala gestión del agua producida como residuo de la pila. Para mejorar la fiabilidad de una pila de combustible es necesario diagnosticar de una manera oportuna los fallos y así evitar daños que reduzcan el desempeño del módulo o que lo inhabiliten. Este trabajo busca contribuir al mejoramiento de la fiabilidad de las pilas de combustible de baja temperatura y de esta forma favorecer el uso de hidrógeno en la transición a una energía descarbonizada. Para lograrlo, se realizaron tres actividades principales: modelado de una pila de hidrógeno, ajuste paramétrico del modelo desarrollado y, por último, aplicación de técnicas de diagnóstico de fallos basados en modelos. En el laboratorio de Recursos Energéticos Renovables Distribuidos LabDER de la Universitat Politècnica de València, se estudia el desempeño de sistemas híbridos renovables, incluyendo una línea de hidrógeno, desde la producción, almacenamiento y reconversión en electricidad en una pila de combustible, por tanto, se ha podido validar el modelo. En un primer momento se identificó la necesidad de un modelo que emplee la temperatura como señal de salida y que retroalimente el sistema, y que tuviese en cuenta señales propias del módulo comercial; sin embargo, el uso de la temperatura como señal y la no linealidad de las ecuaciones físicas, químicas, eléctricas y empleadas, generan un modelo altamente complejo. El ajuste paramétrico del modelo se realizó empleando algoritmos de optimización. Tomando como base al algoritmo de Enjambre de Partículas, se desarrolló una nueva propuesta llamada Scout GA, este algoritmo fue utilizado en otras aplicaciones y pruebas de convergencia para verificar su desempeño frente al fenómeno de estancamiento prematuro y logrando mejorar la precisión y velocidad de convergencia de otras propuestas. Como resultado de la validación de este modelo, en una primera simulación usando datos reales de funcionamiento correspondientes a 1500 segundos, el error de simulación fue del 2,21% en la señal de tensión y del 1,97% en la señal de temperatura, obteniendo un error medio del 2,09%. En un segundo conjunto de datos de algo más de 2.500 segundos de funcionamiento, el error de simulación fue del 2,40% y del 1,96% para las señales de tensión y temperatura, respectivamente. Se estima que el error medio de simulación para ambas señales y condiciones de funcionamiento similares es inferior al 2,5%. Buscando mejorar la fiabilidad de la pila, se realizó el trabajo de diagnóstico de fallos, este partió de la simulación de fallos, mediante la modificación de algunas señales de entrada del modelo, los fallos se caracterizaron mediante el tratamiento estadístico de 12 residuos, obteniendo firmas de fallos, que, en su conjunto, formaron una matriz de fallos. Luego, un algoritmo de diagnóstico propuesto permitió identificar y aislar 14 fallos. permitiendo concluir que, el modelo predice eficazmente los fallos de las pilas PEMFC y podría extrapolarse a otras pilas de combustible. / [CA] Les piles de combustibles són dispositius d'un cost elevat i fràgils davant ambients contaminats o condicions inadequades d'operació com: temperatures extremes o dolenta gestió de l'aigua produïda com a residu de la pila. Per a millorar la fiabilitat d'una pila de combustible és necessari diagnosticar d'una manera oportuna les fallades i així evitar danys que reduïsquen l'acompliment del mòdul o que l'inhabiliten. Este treball busca contribuir al millorament de la fiabilitat de les piles de combustible de baixa temperatura i d'esta manera afavorir l'ús d'hidrogen en la transició a una energia *descarbonizada. Per a aconseguir-ho, es van realitzar tres activitats principals: modelatge d'una pila d'hidrogen, ajust paramètric del model desenvolupat i, finalment, aplicació de tècniques de diagnòstic de fallades basades en models. En el laboratori de Recursos Energètics Renovables Distribuïts *LabDER de la Universitat Politècnica de València, s'estudia l'acompliment de sistemes híbrids renovables, incloent-hi una línia d'hidrogen, des de la producció, emmagatzematge i reconversió en electricitat en una pila de combustible, per tant, s'ha pogut validar el model. En un primer moment es va identificar la necessitat d'un model que empre la temperatura com a senyal d'eixida i que retroalimente el sistema, i que tinguera en compte senyals propis del mòdul comercial, no obstant això, l'ús de la temperatura i la no linealitat de les equacions físiques, químiques, elèctriques i tèrmiques empleades, deriven en un model altament complex. L'ajust paramètric del model de pila de combustible es va realitzar emprant algorismes d'optimització. Prenent com a base a l'algorisme d'Eixam de Partícules, es va desenvolupar una nova proposta anomenada Scout GA, aquest algorisme va ser utilitzat en altres aplicacions i proves de convergència per a verificar el seu acompliment enfront del fenomen d'estancament prematur i aconseguint millorar la precisió i velocitat de convergència d'altres propostes. La simulació i identificació del model té un cost computacional entre 7 i 20 ms per iteració, on es van aconseguir errors de simulació menors al 2.5% Com a resultat de la validació d'aquest model, en una primera simulació usant dades reals de funcionament corresponents a 1500 segons, l'error de simulació va ser del 2,21% en el senyal de tensió, del 1,97% en el senyal de temperatura i un error mitjà del 2,09%. En un segon conjunt de dades d'una mica més de 2.500 segons de funcionament, l'error de simulació va ser del 2,40% i del 1,96% per als senyals de tensió i temperatura, respectivament. S'estima que l'error mitjà de simulació per a tots dos senyals i condicions de funcionament similars és inferior al 2,5%. Buscant millorar la fiabilitat de la pila, es va fer el treball de diagnòstic de fallades, aquest va partir de la simulació de fallades, mitjançant la modificació d'alguns senyals d'entrada del model, les fallades es van caracteritzar mitjançant el tractament estadístic de 12 residus, obtenint signatures de fallades, que en el seu conjunt, van formar una matriu de fallades. després un algorisme de diagnòstic proposat, va permetre identificar i aïllar 14 fallades. Permetent concloure que, el model prediu eficaçment les fallades de les piles PEMFC i podria extrapolar-se a altres piles de combustible. / [EN] Fuel cells are high-cost devices that are fragile in contaminated environments or in inadequate operating conditions, such as extreme temperatures or poor water management, produced as battery waste. To improve the reliability of a fuel cell, it is necessary to diagnose failures promptly and thus avoid damage that reduces the module's performance or disables it. This work seeks to contribute to improving the reliability of low-temperature fuel cells and thus promote the use of hydrogen in the transition to decarbonized energy. To achieve this, three main activities were carried out: modeling a hydrogen fuel cell, parametric adjustment of the developed model, and application of model-based fault diagnosis techniques. In the LabDER Distributed Renewable Energy Resources laboratory of the Polytechnic University of Valencia, the performance of renewable hybrid systems is studied, including a hydrogen line, from production, storage, and reconversion into electricity in a fuel cell, therefore, has been able to validate the model. Initially, a fuel cell model that uses temperature as an in/output signal is required. Also, the model must be able to use the reals signals supplied for the commercial module. However, using temperature and an equation set that includes the non-linearity of the physical, chemical, electrical, and thermal equations resulted in a highly complex model. The parametric adjustment of the fuel cell model was performed using optimization algorithms. Based on the Particle Swarm algorithm, a new proposal called Scout GA was developed. This algorithm was used in other applications and convergence tests to verify its performance against the premature stagnation phenomenon and improved the accuracy and speed of convergence of other proposals. The simulation and identification of the model have a computational cost between 7 and 20 ms per iteration, where simulation errors of less than 2.5% were achieved. As a result of the validation of this model, in a first simulation using real operating data corresponding to 1,500 seconds, the simulation error was 2.21% for the voltage signal, 1.97% for the temperature signal, and an average error of 2.09%. In a second data set for slightly more than 2500 seconds of operation, the simulation error was 2.40% and 1.96% for the voltage and temperature signals, respectively. The average simulation error for both signals and similar operating conditions is estimated to be less than 2.5%. To improve the reliability of the stack, the fault diagnosis work was carried out, starting from the simulation of faults by modifying some input signals of the model; the faults were characterized by the statistical treatment of 12 residuals, obtaining fault signatures, which formed a fault matrix. Then, a proposed diagnostic algorithm allowed to identify and isolate 14 faults. Allowing to conclude that the model effectively predicts the PEMFC stack faults and could be extrapolated to other fuel cells. / Ariza Chacón, HE. (2024). Contribuciones al modelado y diagnóstico de fallos en PEMFC para mejorar la fiabilidad en sistemas híbridos renovables [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203614

The nanoparticles of zirconium oxide, sulfated and phosphated zirconia were used to modify a Nafion membrane in order to improve its water retention, thermal stability, proton conductivity and methanol permeability so that it can be used at higher temperatures in fuel cell. These modified Nafion nanocomposite membrane with inorganic nanoparticles have been designed to run at operating temperatures between 120 oC and 140 oC because higher temperature operation reduces the impact of carbon monoxide poisoning, allows attainment of high power density and reduces cathode flooding as water is produced as vapor. The inorganic nanoparticles were incorporated within the Nafion matrix by recast, ion exchange and impregnation methods. The membrane properties were determined by ion exchange capacity (IEC), water uptake, methanol permeability and proton conductivity. The characterization of the inorganic nanoparticles within the nanocomposite membranes was determined by X-Ray diffraction (XRD), Brunau-Emmett-Teller (BET) surface area and Fourier transform infrared spectroscopy (FTIR) for structural properties. Thermal gravimetric analysis (TGA) and Differential scanning calorimetry (DSC) were used to determine the thermal properties, and the morphological properties were probed by Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). Pristine ZrO2, sulfated and phosphated ZrO2 nanoparticles were synthesized successfully. The particle sizes ranged from 30 nm to 10 nm respectively. The resulted particles were incorporated to a Nafion membrane with good dispersity. The conductivity of the nanocomposite membrane were around 0.1037 S/cm at 25 oC with a higher water uptake of 42 %. These results were confirmed by the highest IEC value of 1.42 meg.g-1 of Nafion/ S-ZrO2 nanocomposites membrane. These high IEC value may due to the incorporation of superacid S-ZrO2 nanoparticles which increased the membrane acid property for providing new strong acid site. / Chemical Engineering / M. Tech. (Chemical Engineering)

Οι σημαντικές περιβαλλοντικές επιπτώσεις που απορρέουν από τις ανθρώπινες δραστηριότητες έχουν οδηγήσει την επιστημονική κοινότητα σε αναζήτηση πιο αποδοτικών και φιλικών προς το περιβάλλον τεχνολογιών παραγωγής ενέργειας. Σε αυτά τα πλαίσια η τεχνολογία των κελιών καυσίμων έχει προσελκύσει σημαντικό ενδιαφέρον. Τα κελιά καυσίμου μετατρέπουν τη χημική ενέργεια που είναι αποθηκευμένη σε ένα καύσιμο απ’ ευθείας σε ηλεκτρική, χωρίς να υπόκεινται στους περιορισμούς του κύκλου Carnot. Συγκριτικά με τα υπόλοιπα κελιά καυσίμου, το κελί καυσίμου στερεού οξειδίου (SOFC), ξεχωρίζει κυρίως λόγω της υψηλής απόδοσής του. Στην παρούσα εργασία γίνεται εκτίμηση των παραμέτρων μαθηματικών προτύπων κελιών καυσίμου στερεού οξειδίου, με σκοπό να αναλυθούν οι ηλεκτροχημικές διεργασίες που πραγματοποιούνται κατά τη λειτουργία τους. Αρχικά περιγράφεται η λειτουργία του SOFC και αναπτύσσονται οι εξισώσεις που συνιστούν το μαθηματικό πρότυπο SOFC. Επίσης, παρουσιάζονται επιλεγμένα μαθηματικά πρότυπα που αναφέρονται στη βιβλιογραφία για την προσομοίωση των διεργασιών που λαμβάνουν χώρα στο SOFC. Στην συνέχεια, περιγράφεται η μέθοδος βελτιστοποίησης που χρησιμοποιείται για την εκτίμηση των παραμέτρων των μαθηματικών προτύπων. Τέλος, παρατίθενται τα αποτελέσματα και τα συμπεράσματα που απορρέουν από την προσομοίωση και την εκτίμηση παραμέτρων καθώς και προτάσεις για μελλοντική έρευνα. / Human impact on the environment, has led the scientific community in research of more efficient and environmentally friendly energy production technologies. In this frame, fuel cell technology has attracted considerable attention. Fuel cells convert the chemical energy stored in a fuel into electrical without being subject to the Carnot cycle limitations. Compared to other types of fuel cells, solid oxide fuel cell (SOFC) stands out mainly due to its high performance. In the present work, parameter estimation of solid oxide fuel cell mathematical prototypes is implemented, in order to analyze the electrochemical processes taking place during SOFC operation. Initially, SOFC performance is described and the SOFC prototype equations are developed. Furthermore, selected mathematical prototypes reported in literature for the simulation of the processes taking place in the SOFC are presented. Then, the simulation method used for the parameter estimation of the mathematical prototypes is described. Finally, simulation results and conclusions derived from parameter estimation as well as suggestions for future work are given.

Direct methanol fuel cells (DMFC) are appealing as a power source for portable devices as they do not require recharging with an electrical outlet. However, the DMFC technology is confronted with the high crossover of methanol fuel from the anode to the cathode through the currently used Nafion membrane, which not only wastes the fuel but also poisons the cathode platinum catalyst. With an aim to overcome the problems encountered with the Nafion membrane, this dissertation focuses on the design and development of new polymeric membrane materials for DMFC and a fundamental understanding of their structure-property-performance relationships. Several polymeric blend membranes based on acid-base interactions between an aromatic acidic polymer such as sulfonated ploy(ether ether ketone) (SPEEK) and an aromatic basic polymer such as heterocycle tethered poly(sulfone) (PSf) have been explored. Various heterochylces like nitro-benzimidazole (NBIm), 1H-Perimidine (PImd), and 5-amino-benzotriazole (BTraz) have been tethered to PSf to understand the influence of pKa values and the size of the hetrocycles. The blend membranes show lower methanol crossover and better performance in DMFC than plain SPEEK due to an enhancement in proton conductivity through acid-base interactions and an insertion of the heterocycle side groups into the ionic clusters of SPEEK as indicated by small angle Xray scattering and TEM data. The SPEEK/PSf-PImd blend membrane shows the lowest methanol crossover due to the larger size of the side groups, while the SPEEK/PSf-BTraz blend membrane shows the highest proton conductivity and maximum power density. To further investigate the methanol-blocking effect of the heterocycles, N,N’-Bis- (1H-benzimidazol-2-yl)-isophthalamide (BBImIP) having two amino-benzimidazole groups bonded to a phenyl ring has been incorporated into sulfonated polysulfone (SPSf) and SPEEK membranes. With two 2-amino-benzimidazole groups, which could greatly increase the proton transfer sites, and three phenyl rings, which are compatible with the aromatic polymers, the BBImIP/SPSf and BBImIP/SPEEK blend membranes show suppressed methanol crossover and increased fuel cell performance in DMFC. Novel sulfonated copolymers based on poly(aryl ether sulfone) (SPS-DP) that exhibit low methanol crossover have been synthesized and explored as a methanol-barrier center layer in a multilayer membrane configuration having SPEEK as the outer layers. These multilayer membranes exhibit better performance in DMFC than plain SPEEK and Nafion 115 membranes due to suppressed methanol crossover. To address the issue of incompatibility between the new hydrocarbon-based membranes synthesized and the Nafion ionomer used in the catalyst layer in fabricating membrane-electrode assemblies (MEAs), the MEAs have been fabricated with the SPEEK membranes and 10 to 30 % SPEEK ionomer in the catalyst layer. These MEAs exhibit better performance in DMFC compared to the MEAs fabricated with the SPEEK membranes and Nafion ionomer in the catalyst layer due to lower interfacial resistance. / text

A test system for the performance analysis of a novel thermally regenerative fuel cell (TRFC) using propiophenone and hydrogen as the oxidant and fuel respectively was designed and built. The test system is capable of either hydrogen-air or hydrogen-propiophenone operation. Membrane electrode assemblies (MEAs) were made using commercial phosphoric acid-doped polybenzimidazole (PBI) membranes and commercial electrodes. Using Pt/carbon paper electrodes with a catalyst loading of 1mg/cm2 and a membrane with an acid doping level of 10.2 mol acid/mol of polymer repeat unit, a maximum performance of 212 mW/cm2 at a current density of 575 mA/cm2 was achieved for baseline hydrogen-air testing at 110°C. Problems were encountered, however, in achieving consistent, reproducible performance for in-house fabricated MEAs. Furthermore, ex-situ electrochemical impedance spectrometry (EIS) showed that the phosphoric acid-doped PBI was unstable in the propiophenone and that acid-leaching was occurring. In order to have MEAs with consistent characteristics for verifying the test system performance, commercial phosphoric acid-doped PBI membrane electrode assemblies were used. At a temperature of 160°C and atmospheric pressure with hydrogen and air flowrates of 150 mL/min and 900 mL/min respectively a maximum power density of 387 mW/cm2 at a current density of 1.1 A/cm2 was achieved. This performance was consistent with the manufacturer’s specifications and these MEAs were subsequently used to verify the performance of TRFC test system despite the EIS results that indicated that acid-leaching would probably occur. The Pt catalyzed commercial MEAs achieved very limited performance for the hydrogenation of the ketone. However, the performance was less than but comparable to similar results previously reported in the literature by Chaurasia et al. [1]. For pure Pt catalyst loading of 1 mg/cm2, using a commercial PBI MEA operating at 160°C and atmospheric pressure, the maximum power density was 40 µW/cm2 at a current density of 1.3 mA/cm2. A 16 hour test was conducted for these conditions with a constant 1 ohm load, successfully demonstrating the operation of the test system. The test system will be used in the development of better catalysts for ketone hydrogenation. / Thesis (Master, Chemical Engineering) -- Queen's University, 2012-10-12 10:00:58.854

The Liquid Salt Cooled Reactor (LSCR) provides several potential benefits compared to pressurized water-cooled reactor systems. These include low operating pressure of the liquid salt coolant, the high burnup tolerance of the fuel, and the high operating temperatures which leads to increases in efficiency. However, due to inherently low heavy metal loading, the fuel cycle design presents specific challenges. In order to study options for optimizing the fuel design and fuel cycle, SCALE6.1 was used to create simplified models of the reactor and look at various parameters. The primary parameters of interest included packing factor and fuel enrichment. An economic analysis was performed on these results by developing a simple fuel cycle cost (FCC) model that could be used to compare the different options from an economic standpoint. The lithium enrichment of the FLiBe coolant was also investigated. The main focus was to understand the practical limitations associated with the Li-7 enrichment and whether it could be used for beneficial purposes. The main idea was to determine whether a lower-than-equilibrium enrichment could be used at reactor start up so that the Li-6 isotope acts as a burnable absorber. The results for the lithium enrichment study showed that the enrichment converges over time, but the amount of time required to reach steady state is much too long and the FLiBe coolant could not be utilized for reactivity control as a burnable absorber. The results found through this research provide reasonable guidelines for expected costs and narrow down the types of configurations that should be considered as fuel design options for the LSCR. Additionally, knowledge was gained on methods for modeling the system not only accurately but also efficiently to reduce the required computing power and time.

There is at present some uncertainty as to what the roles and requirements of the next generation of UAVs might be and the configurations that might be adopted. The incorporation of technological features on these designs is also a significant driving force in their configuration, efficiency, performance abilities and operational requirements. The objective of this project is thus to provide some insight into what the next generation of technologies might be and what their impact would be on the rest of the aircraft. This work involved the conceptual designs of two new relevant full-scale UAVs which were used to integrate a select number of these advanced technologies. The project was a CASE award which was linked to the Flaviir research programme for advanced UAV technologies. Thus, the technologies investigated during this study were selected with respect to the objectives of the Flaviir project. These were either relative to those already being developed as course of the Flaviir project or others from elsewhere. As course of this project, two technologies have been identified and evaluated which fit this criterion and show potential for use on future aircraft. Thus we have been able to make a contirubtion knowledge in two gaps in current aerospace technology. The first of these studies was to investigate the feasibility of using a low cost mechanical thrust vectoring system as used on the X-31, to replace conventional control surfaces. This is an alternative to the fluidic thrust vectoring devices being proposed by the Flaviir project for this task. The second study is to investigate the use of fuel reformer based fuel cell system to supply power to an all-electric power train which will be a means of primary propulsion. A number of different fuels were investigated for such a system with methanol showing the greatest promise and has been shown to have a number of distinct advantages over the traditional fuel for fuel cells (hydrogen). Each of these technologies was integrated onto the baseline conceptual design which was identified as that most suitable to each technology. A UCAV configuration was selected for the thrust vectoring system while a MALE configuration was selected for the fuel cell propulsion system. Each aircraft was a new design which was developed specifically for the needs of this project. Analysis of these baseline configurations with and without the technologies allowed an assessment to be made of the viability of these technologies. The benefits of the thrust vectoring system were evaluated at take-off, cruise and landing. It showed no benefit at take-off and landing which was due to its location on the very aft of the airframe. At cruise, its performance and efficiency was shown to be comparable to that of a conventional configuration utilizing elevons and expected to be comparable to the fluidic devices developed by the Flaviir project. This system does however offer a number of benefits over many other nozzle configurations of improved stealth due to significant exhaust nozzle shielding.The fuel reformer based fuel cell system was evaluated in both all-electric and hybrid configurations. In the ell-electric configuration, the conventional turboprop engine was completely replaced with an all-electric powertrain. This system was shown to have an inferior fuel consumption compared to a turboprop engine and thus the hybrid system was conceived. In this system, the fuel cell is only used at loiter with the turboprop engine being retained for all other flight phases. For the same quantity of fuel, a reduction in loiter time of 24% was experienced (compared to the baseline turboprop) but such a system does have benefits of reduced emissions and IR signature. With further refinement, it is possible that the performance and efficiency of such a system could be further improved. In this project, two potential technologies were identified and thoroughly analysed. We are therefore able to say that the project objectives have been met and the project has proven worthwhile to the advancement of aerospace technology. Although these systems did not provide the desired results at this stage, they have shown the potential for improvement with further development.

A new family of perovskite titanates with formulae La4+nSr8-nTi12-nMnnO38 and La4Sr8Ti12-nMnnO38-δ have been investigated as potential fuel electrode materials for SOFCs. The series La4+nSr8-nTi12-nMnnO38 present layered domains within their structure. As such layers appear to have a large negative effect over the electrochemical properties only a few compounds have been characterised. The series La4Sr8Ti12-nMnnO38-δ present a rhombohedral (R-3c) unit cell at room temperature which becomes cubic when increasing the temperature up to 900°C both in air and in reducing conditions. The primitive volume correlates with the oxygen content for the reduced samples. TGA and magnetic studies have revealed that the Mn present is mainly as Mn⁺³. Preliminary HRTEM investigations have revealed that some crystallographic shears distributed randomly within a perovskite matrix remain in the structure, which implies that the oxygen overstoichiometry is compatible with rhombohedral distortions in the oxygen sublattice. Mn substitution does not have a large impact on the bulk conductivity of the phases studied, which remains close to the values observed in other related titanates, although the grain boundary contributions are largely improved. Relatively low polarisation resistances were observed under both hydrogen and methane conditions for the lowest n compounds of the series. The anodic overpotential for n=1 was fairly low to those reported in the literature for other materials and especially for titanate-based anodes, i.e. a value of 55mV at 0.5A/cm2, at 950°C, under wet hydrogen was obtained. Additionally, a value 72mV was obtained in the same conditions under methane. These values indicate that the use of Mn as dopant for perovskite-related titanates enhanced electrochemical performance of these anodes, especially at high temperatures.