Fabrice Mauvy
University of Bordeaux
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Publication
Featured researches published by Fabrice Mauvy.
Journal of Materials Chemistry | 2012
Alexis Grimaud; Fabrice Mauvy; Jean Marc Bassat; Sébastien Fourcade; Mathieu Marrony; Jean Claude Grenier
The result of the substitution of Pr3+ by Sr2+ in the 214 Ruddlesden-Popper Pr2NiO4+δ material was studied with regard to its electrochemical properties as a H+-SOFC cathode. Structural characterizations as well as physical properties of the Pr2−xSrxNiO4+δ compounds (x ≤ 0.50), in particular hydration as a function of water partial pressure, have shown that oxygen over-stoichiometry and oxygen exchange with atmosphere decrease with increasing x, which has been correlated with the stabilization of the 214 structure by Sr2+ substitution. Electrochemical studies on the oxygen reduction versus hydration have allowed determination of the rate determining steps of the formation of water and evidence the role of protons in Pr2NiO4+δ in contrast to Pr2−xSrxNiO4+δ oxides. It has been concluded that triple mixed conductivity (i.e. protonic, ionic as well as electronic conductivities) exists in this nickelate Pr2NiO4+δ. In addition, there was evidence for strong correlation between the insertion of protonic defects and additional oxygen in the interstitial position of Pr2NiO4+δ.
Journal of Materials Chemistry | 2014
Alexis Grimaud; Jean-Marc Bassat; Fabrice Mauvy; M. Pollet; Alain Wattiaux; Mathieu Marrony; Jean-Claude Grenier
PrBaCo2−xFexO5+δ solid solution is investigated in order to understand the Oxygen Reduction Reaction (ORR) and water formation occurring at the H+-SOFC cathode. Careful attention is paid to the study of the physical properties as a function of composition by Thermogravimetry Analysis (TGA), Mossbauer spectroscopy, electrical conductivity and Seebeck coefficient measurements, with the aim to establish the correlation existing with the ORR activity for these Mixed Ionic Electronic Conductors (MIEC). The oxygen diffusion coefficients are determined by Electrical Conductivity Relaxation (ECR) and Isotopic Exchange Depth Profile (IEDP) coupled with Secondary Ion Mass Spectroscopy (SIMS) methods. An electrochemical study is then carried out and shows that the amount of oxygen vacancies is the most influential parameter. Indeed, it allows some hydration of PrBaCo2O5+δ oxide and the formation of protonic defects that can induce protonic diffusivity in these MIEC oxides.
ECS Transactions | 2009
Jean Claude Grenier; Fabrice Mauvy; C. Lalanne; Jean-Marc Bassat; Florent Chauveau; Julie Mougin; Julian Dailly; Mathieu Marrony
Until now, most cathode materials used in high temperature ceramic solid electrolyte oxide cells (SEOC) are perovskite-type MEIC compounds, AMO3-δ, showing oxygen sub-stoichiometry. Recently, a new family of overstoichiometric oxides, formulated A2MO4+δ with A = La, Nd, Pr, Sr and M = Ni, Cu, has been investigated. Due to their basic properties (large D* and k coefficients, high electrical conductivity), the nickelate compounds have been especially used in various applications. Nd2NiO4 and Pr2NiO4 exhibit very promising electrochemical properties down to temperature as low as 600{degree sign}C, as ITSOFC cathodes as well as PCFC cathodes (they are stable under moist air (3 -10 % H2O). In addition, encouraging cell tests (SOFC and PCFC) have been performed with both nickelates. Furthermore, these materials have been also used as HTSE anodes and first results show excellent performances. Thus, it appears that these materials show an extremely high flexibility for being used as air electrode in very different conditions in terms of oxygen partial pressure or/and water content. This is explained on the basis of structural features of these materials and the great ability of these compounds for accommodating the oxygen non-stoichiometry.
Functional Materials for Sustainable Energy Applications | 2012
Jean-Claude Grenier; Jean-Marc Bassat; Fabrice Mauvy
Abstract: In this chapter, after a brief overview of the oxygen reduction reaction at the cathode side of a solid oxide fuel cell (SOFC), the main requirements for cathode materials are discussed as well as the conventional compounds that have been intensively studied during the last two decades. In the second part of the chapter, innovative materials (mixed ionic and electronic conducting oxides) are considered from the viewpoint of structural aspects and transport properties. Special attention is devoted to the layered compounds, Ln2NiO4 + δ, which exhibit promising properties (oxygen diffusivity, electrocatalytic properties). Their performances as SOFC cathode materials are compared to those of other materials. Finally, the flexibility of these materials as oxygen electrodes in protonic ceramic fuel cells and electrolyzers is emphasized. This is discussed in terms of the materials’ structural features.
Defect and Diffusion Forum | 2012
Christine Frayret; Antoine Villesuzanne; M. Pouchard; Fabrice Mauvy; Jean Marc Bassat; Jean Claude Grenier
In CeO2-based solid electrolytes, it has been shown that point defects are directly responsible for oxygen ionic conduction. The ionic conductivity is strongly affected by the anion vacancy concentration which is enhanced by doping with aliovalent cations. When rare earth sesquioxides such as La2O3, Gd2O3, Sm2O3, Y2O3 are added to CeO2, the dopant cation substitutes for the cerium ion, and oxygen vacancies are created for charge compensation. Incorporation of trivalent dopants into CeO2 at the Ce4+ sites can be depicted by the following defect reaction (expressed in Kröger-Vink notation):
Electrochimica Acta | 2010
J. Dailly; Sébastien Fourcade; A. Largeteau; Fabrice Mauvy; Jean-Claude Grenier; M. Marrony
Solid State Ionics | 2008
Hui Zhao; Fabrice Mauvy; C. Lalanne; Jean-Marc Bassat; Sébastien Fourcade; Jean-Claude Grenier
Journal of Power Sources | 2010
Florent Chauveau; Julie Mougin; Jean-Marc Bassat; Fabrice Mauvy; Jean-Claude Grenier
Fuel Cells | 2009
G. Taillades; J. Dailly; Mélanie Taillades-Jacquin; Fabrice Mauvy; A. Essouhmi; Mathieu Marrony; C. Lalanne; S. Fourcade; Deborah J. Jones; Jean-Claude Grenier; Jacques Rozière
Solid State Ionics | 2013
Benoît Philippeau; Fabrice Mauvy; Cécile Mazataud; Sébastien Fourcade; Jean-Claude Grenier