المؤلفون: de Windt, Sébastien

المساهمون: Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), Université Clermont Auvergne, Katia Guerin, Marc Dubois

المصدر: https://theses.hal.science/tel-04480242Test ; Matériaux. Université Clermont Auvergne, 2023. Français. ⟨NNT : 2023UCFA0093⟩.

مصطلحات موضوعية: Oxyfluoride, Disordered material, Cathode, Elemental fluorine, Oxyfluorure, Matériau désordonné, Fluor moléculaire, [CHIM.MATE]Chemical Sciences/Material chemistry

الوصف: The present PhD work is part of the global research on electro-chemical energy storage, and tackle to its level a major challenge faced by the current Li-ion battery industry: transitioning from the nickel-manganese-cobalt (NMC) cathode technology to cobalt-free, nickel-free materials.Cation-disordered rocksalts (CDRS) are a recent family of cathode active material which meets these requirements. Both the scientific community and the sponsor of the present work, Umicore, show strong interest in these materials, which however suffer from critical capacity fade after a few cycles. Nonetheless, their oxyfluorination was identified as an effective way to address this weakness. Thus, this work is about gas-solid fluorination, first applied to the manganese oxides precursors, then aiming for the effective synthesis of a Li_Mn_O_F-like CDRS.Innovative protocols were developed to efficiently collect critical information like activation temperatures or reactivity shifts, in order to target only relevant conditions when performing a series of syntheses. In addition, special attention was given to the characterization methodology, including control series, systematic cross-check of multiple techniques and development of dedicated analysis procedures. This document thus reports how the fluorination of MnO proceeds via a mechanism of pure insertion and leads to the formation of a collection of stable and finely tunable manganese oxyfluorides, including stoichiometric MnOF. It details how the fluorination of Mn3O4 and Mn2O3 leads to different oxyfluorides, according to a more complex mechanism. It discloses how the attempts to use all-solid-state reactions to insert lithium into manganese oxyfluorides lead to a systematic phase segregation between oxides and fluorides, and in opposition how the fluorination of lithium manganese oxides leads to oxyfluorides. Last, it reveals how one-pot fluorinations of mixed lithium and manganese precursors produced at least two compounds with no database records, the structure of which are ...

العلاقة: NNT: 2023UCFA0093; tel-04480242; https://theses.hal.science/tel-04480242Test; https://theses.hal.science/tel-04480242/documentTest; https://theses.hal.science/tel-04480242/file/2023UCFA0093_DE_WINDT.pdfTest

الإتاحة: https://theses.hal.science/tel-04480242Test
https://theses.hal.science/tel-04480242/documentTest
https://theses.hal.science/tel-04480242/file/2023UCFA0093_DE_WINDT.pdfTest

المؤلفون: Ahmad, Yasser, Dubois, Marc, Guérin, Katia, Hamwi, André, Flahaut, Emmanuel

المساهمون: Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)

المصدر: ISSN: 0925-8388 ; Journal of Alloys and Compounds ; https://hal.science/hal-01639477Test ; Journal of Alloys and Compounds, 2017, 726, pp.852-859. ⟨10.1016/j.jallcom.2017.08.001⟩.

مصطلحات موضوعية: Reinforcement effect, Extra-capacity, Energy density, Lithium battery, Cathode, Fluorinated carbon nanotubes, [CHIM.OTHE]Chemical Sciences/Other, [CHIM.MATE]Chemical Sciences/Material chemistry

الوصف: International audience ; Fluorinated carbon nanotubes used as cathode material exhibit a capacity exceeding the theoretical value when used in primary lithium battery. The measured experimental capacity, the faradic yield and the energy density were increased, exceeding the expected theoretical values for sub-fluorinated few walled carbon nanotubes (FWCNTs).Although the molar carbon/fluorine ratio was only of 0.37 (i.e CF0.37), an experimental capacity of 900 mAh.g−1 was obtained which is higher than the theoretical value of 521 mAh.g−1. With the same material, an unprecedented energy density of 2565 Wh kg−1 was reached associated with a faradic yield of 172%. The materials were deeply characterized using TEM, Raman and solid state 13C and 19F NMR in order to explain the extra-capacity. Such high electrochemical values can be correlated to the reinforcement effect of the central tube(s), coupled with a low amount of structural defects.

العلاقة: hal-01639477; https://hal.science/hal-01639477Test; https://hal.science/hal-01639477/documentTest; https://hal.science/hal-01639477/file/Ahmad_19658.pdfTest

الإتاحة: https://doi.org/10.1016/j.jallcom.2017.08.001Test
https://hal.science/hal-01639477Test
https://hal.science/hal-01639477/documentTest
https://hal.science/hal-01639477/file/Ahmad_19658.pdfTest

المؤلفون: Eveillard, Fabien, Leroux, Fabrice, Batisse, Nicolas, Delbègue, Diane, Guérin, Katia

المساهمون: Institut de Chimie de Clermont-Ferrand (ICCF), Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA)

المصدر: ISSN: 0022-4596.

مصطلحات موضوعية: MultiMetallic template, Prussian blue analogues, Solid gas fluorination, ASSB, Cathode materials, Cyclic voltammetry, Solid polymer electrolyte, [CHIM]Chemical Sciences

الوصف: International audience ; Conversion cathodes such as metal fluorides are particularly interesting for their theoretical capacities up to 711 mAh/g when used in Li-ion batteries. However, they generally suffer from high hysteresis and/or poor cyclability. To overcome these problems, ternary metal fluorides are being explored to improve electrochemical properties compared to the usual binary fluorides: a polymer electrolyte membrane is also used to avoid undesirable cathode-electrolyte reactions and to assess the compatibility of such cathode materials with All Solid State Batteries (ASSB). Among the multi-metallic models, copper hexacyanoferrate Cu3[Fe(CN)6]2.nH2O from the Prussian blue analogue family (PBA), is fluorinated under pure fluorine gas at selected temperatures according to preliminary thermogravimetric mass spectrometry analyses. Using X-ray absorption spectroscopy and diffraction, an inverse perovskite structure [Cu(H2O)4]3·(FeF6)2 is identified at a fluorination temperature of 140 °C and an intimate mixture of CuF2 and FeF3 is formed at 350 °C. The cyclic voltammogram of the latter compared to that of a ball-milled sample of similar composition CuF2/FeF3 highlights the advantages of MMTF multi-metallic template fluorination for electrochemical properties, interpreted by the high level of homogeneous dispersion of the redox centers obtained with this method compared to the mechanical milling reference evaluated by SEM. The fluorides are also found to be compatible with the commercial solid polymer electrolyte membrane PEO-LiTFSI (Poly Ethylene Oxide impregnated with Lithium bis(trifluoromethanesulfonyl)imide), underlining the suitability of the MMTF-prepared cathodes for use in the ASSB.

العلاقة: hal-03805301; https://uca.hal.science/hal-03805301Test

الإتاحة: https://doi.org/10.1016/j.jssc.2022.123031Test
https://uca.hal.science/hal-03805301Test

المؤلفون: André, Pascal, Barinov, Yu, Faure, Géraldine, Shkol'Nik, Sergey

المساهمون: Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS), A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences Moscow (RAS)

المصدر: ISSN: 0022-3727 ; EISSN: 1361-6463.

مصطلحات موضوعية: plasma discharge, water plasma, air plasma, molecular spectroscopy, thermal non equilibrium, tap-water cathode, [PHYS]Physics [physics], [CHIM.ORGA]Chemical Sciences/Organic chemistry, [SDV.CAN]Life Sciences [q-bio]/Cancer, [SPI.PLASMA]Engineering Sciences [physics]/Plasmas

الوصف: International audience ; The possibility of creating a steady-burning low-current discharge in an air flow atatmospheric pressure using a cathode of weakly conducting liquid (tap water) and a constantvoltagepower source is presented. The experiments were carried out at currents of 100–300mA and air flows of 5–20 slpm. Probe and spectroscopic measurements were performed todetermine the plasma parameters. The discharge spectrum was simulated and the plasmacomposition was calculated. It was found that a nonequilibrium moist high-pressureplasma with relatively low gas temperatures (>~2000 K) and substantially higher electrontemperatures (>~6000 K) and high electron densities (<~10^21 m−3) is generated in thedischarge channel. According to the calculations, the plasma contains high concentrations ofthe chemically active radicals ОН (~10^22–10^23 m−3) and O (~10^22–10^23 m−3). The obtainedresults are compared with the available results in the literature regarding experiments andcalculations for glow discharges in gas flows at atmospheric pressure.

العلاقة: hal-01885991; https://hal.science/hal-01885991Test; INSPIRE: 1864510

الإتاحة: https://doi.org/10.1088/1361-6463/aadfadTest
https://hal.science/hal-01885991Test

المؤلفون: Delbegue, Diane

المساهمون: Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS), Université Clermont Auvergne 2017-2020, Katia Guerin

المصدر: https://theses.hal.science/tel-01725828Test ; Matériaux. Université Clermont Auvergne [2017-2020], 2017. Français. ⟨NNT : 2017CLFAC046⟩.

مصطلحات موضوعية: Fluorination, Iron fluoride, Lithium-ion battery, Cathode material, XAS, XRD, Mossbauer, Fluoration, Fluorure de fer, Batterie lithium-ion, Cathode, DRX, [CHIM.MATE]Chemical Sciences/Material chemistry

الوصف: The lithium-ion batteries are the current solution for electrochemical energy storage. However, their performances are limited by the cathode materials, such as LiCoO2, LiMn2O4 or LiFePO4 of specific capacity lower than 160 mAh/g. Many materials are good candidates to improve this capacity such as iron trifluoride of theoretical capacity of 711 mAh.g-1. This work will present the synthesis of FeF3 through different fluorination ways. The resulting materials will be characterized owing to their structure by XRD, Mössbauer, Raman and IR spectroscopies and their texture by nitrogen adsorption isotherms at 77K and SEM. After that, the electrochemical properties will be evaluated and compared. Finally, the study of the electrochemical mechanism of this family of compounds will be led with a method of characterization “in operando” : the X-rays absorption spectroscopy (XAS). ; Les batteries lithium ions sont la technologie de référence pour le stockage électrochimique de l’énergie. Cependant, les matériaux cathodiques de ces batteries comme LiCoO2, LiMn2O4 ou LiFePO4 présentent une capacité spécifique limitée (<160 mAh/g). De nombreux composés sont à l’étude pour améliorer cette performance dont le fluorure de fer (III) en raison de sa capacité théorique de 711 mAh.g-1. Ce travail présentera la synthèse de FeF3 par différentes méthodes de fluoration. Les matériaux obtenus seront comparés en termes de structures et de liaison (DRX, Mössbauer, spectroscopies IR et Raman) mais aussi de texture (isothermes d’adsorption à l’azote à 77K). Les propriétés électrochimiques des matériaux obtenus seront également comparées et testées. Enfin, l’étude du mécanisme électrochimique de cette famille de composés sera menée via une méthode de caractérisation « in operando » : la spectroscopie d’absorption des rayons X (XAS).

العلاقة: NNT: 2017CLFAC046; tel-01725828; https://theses.hal.science/tel-01725828Test; https://theses.hal.science/tel-01725828/documentTest; https://theses.hal.science/tel-01725828/file/2017CLFAC046_DELBEGUE.pdfTest

الإتاحة: https://theses.hal.science/tel-01725828Test
https://theses.hal.science/tel-01725828/documentTest
https://theses.hal.science/tel-01725828/file/2017CLFAC046_DELBEGUE.pdfTest

المؤلفون: Lefort, André, Abbaoui, M'Hammed

المساهمون: Laboratoire arc électrique et plasmas thermiques (LAEPT), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Z. Koalaga and P. André

المصدر: 1st International Symposium on Electrical Arc and Thermal Plasmas in Africa (ISAPA)
https://hal.science/hal-00694585Test
1st International Symposium on Electrical Arc and Thermal Plasmas in Africa (ISAPA), Oct 2011, Ouagadougou, Burkina Faso. pp.012007, ⟨10.1088/1757-899X/29/1/012007⟩

مصطلحات موضوعية: Arc root, cathode spot, vacuum, silver, energy flux, PACS 52.80.Mg Arc, sparks, lightning, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [SPI.PLASMA]Engineering Sciences [physics]/Plasmas, [SPI.MAT]Engineering Sciences [physics]/Materials

جغرافية الموضوع: Burkina Faso

الوقت: Ouagadougou, Burkina Faso

الوصف: 11 ; International audience ; The cathode spot is theoretically analyzed here for a 10A current and a silver contact in vacuum. The main equations leading to the values of physical characteristics are detailed and resolved according to the radius r in the domain 0.5-1.5µA. The choice of this field is imposed by the limits of the current density and time of appearance of the metal vapour. The findings show that when they are created the spots have cathode radius that fall to low values of field. Under the action of saturated vapour pressures higher radius of the spot will grow but its growth is limited by its lifetime.

العلاقة: hal-00694585; https://hal.science/hal-00694585Test

الإتاحة: https://doi.org/10.1088/1757-899X/29/1/012007Test
https://hal.science/hal-00694585Test

المؤلفون: Abbaoui, M'Hammed, Lefort, André, Carvou, Erwann, Sallais, Damien, Mitchell, James, Ben Jemaa, Noureddine

المساهمون: Laboratoire arc électrique et plasmas thermiques (LAEPT), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

المصدر: ISSN: 1009-0630 ; Plasma Science and Technology ; https://hal.science/hal-01025703Test ; Plasma Science and Technology, 2014, 16 (5), pp.471-478. ⟨10.1088/1009-0630/16/5/06⟩.

مصطلحات موضوعية: arc root, cathode spot, anode spot, erosion, contacts, current density, PACS, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]

الوصف: 8 ; International audience ; The erosion of silver contacts due to break arcs with length proportional to time and of variable duration, has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A. The experimental results show that, for arc durations less than 60 µs, the transfer of metal from the anode to the cathode occurs, but after passing this stage, when the two electrodes are separated by greater distances, each will display erosion. This is the result of the diffusion of material outside the space between the two electrodes. In order to interpret these results, we have applied a classical model of the physical phenomena occurring at the base of the arcs. Analysis of the experimental results shows that for an arc duration of less that 15 µs, no distinct cathode base is seen to exist, but beyond this, the cathode displays several spots for a time up to 50 µs, after which they merge into a single spot. Comparison between experiment and theoretical interpretation is reasonable up to 60 µs.

العلاقة: hal-01025703; https://hal.science/hal-01025703Test

الإتاحة: https://doi.org/10.1088/1009-0630/16/5/06Test
https://hal.science/hal-01025703Test

المؤلفون: Messaad, M., Belarbi, A. W., Lefort, A., Abbaoui, M'Hammed

المساهمون: Laboratoire de Physique des Décharges Electriques (LPDE), Université des sciences et de la Technologie d'Oran Mohamed Boudiaf Oran (USTO MB)-Département d'Electrotechnique, Faculté de Génie Electrique, Laboratoire arc électrique et plasmas thermiques (LAEPT), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)

المصدر: Acta Electrotechnica et Informatica ; https://hal.science/hal-00365284Test ; Acta Electrotechnica et Informatica, 2006, 6 (3), pp.64

مصطلحات موضوعية: Vacuum arc, cathode spot, cathode region, current density, power density, spot radius, PACS : 52-80.-s, 52.80.Mg, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]

الوصف: 8 ; International audience ; Experimental and theoretical studies of arc cathode region have been made during several decades and the task is not yet completed, in spite of many efforts and progress. In this work, a numerical model describing the arc cathode region is developed. The model is then applied to a vacuum arc discharge interacting with a Cu cathode at low current (4-50A). The model yields the temperature and electric field strength at the cathode surface, electrons emitted and total current density, cathode spot radius, different kinds of power densities heating and cooling the cathode, and the plasma electron density. The comparison with experimental results shows good agreements.

العلاقة: hal-00365284; https://hal.science/hal-00365284Test

الإتاحة: https://hal.science/hal-00365284Test

المؤلفون: Abbaoui, M'Hammed, Lefort, A., Clain, Stéphane

المساهمون: Laboratoire arc électrique et plasmas thermiques (LAEPT), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mathématiques Blaise Pascal (LMBP), Institute of Electrical and Electronics Engineers, Inc

المصدر: ISDEIV XXI XXIth International Symposium on Discharges and Electrical Insulation in Vacuum ; https://hal.science/hal-00019457Test ; 2004, pp.233-236

مصطلحات موضوعية: Arc root, material nature, cathode, spot, liquid-vapour phases, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]

الوصف: This paper describes a thermo physical phenomena analysis about a silver, copper, aluminium, iron, tungsten or graphite electrode submitted to a high density energy flux. The thermal flux necessary to create a cathode spot is about 1.1012 Wm-2. For the studied metals and for values lower than 1.1011 Wm-2, the liquid phase does not appears and the entire energy coming at the cathode surface diffuses in the electrode. For values upper than 5.1012 Wm-2 a large part of the energy is used for the vaporization and the electrode vaporized length depends of the material nature. The gap situated between the two extreme values 1.1011 Wm-2 and 1.1013 Wm-2 corresponds to the cathode spot with liquid and vapour phases.

العلاقة: hal-00019457; https://hal.science/hal-00019457Test

الإتاحة: https://hal.science/hal-00019457Test

المؤلفون: Messaad, M., Mammar, K., Tioursi, M., Abbaoui, M'Hammed, Lefort, A.

المساهمون: Laboratoire de Physique des Décharges Electriques (LPDE), Université des sciences et de la Technologie d'Oran Mohamed Boudiaf Oran (USTO MB)-Département d'Electrotechnique, Faculté de Génie Electrique, Laboratoire arc électrique et plasmas thermiques (LAEPT), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Université de Saida

المصدر: The First International Conference on Electrical/Electronic Engineering Communication and Physical System ; https://hal.science/hal-00080307Test ; The First International Conference on Electrical/Electronic Engineering Communication and Physical System, 2004, Saida (20000), Algérie

مصطلحات موضوعية: Arc électrique, émission électronique, cathode, champ électrique, température, densité de courant, Pacs 50, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]

جغرافية الموضوع: Saida (20000), Algeria

الوصف: 5 pages ; The current density in arc discharge and especially at the cathode has been a source of controversy for several years. Most of theoretical analysis of arc cathode spot was directed toward determination of the mechanism that provided such high emission current density. The current density is one of the most essential physical quantities for each of the processes in the arc cathode regime. In this paper a review is given on the different equations to calculate the cathodic electron-emission current density and a comparative study is made.

العلاقة: hal-00080307; https://hal.science/hal-00080307Test

الإتاحة: https://hal.science/hal-00080307Test