Frédéric Boschini - Academia.edu (original) (raw)

Papers by Frédéric Boschini

Meeting abstracts, 2019

Fluorophosphate compounds attract much attention as cathode materials for Na-ion batteries. Indee... more Fluorophosphate compounds attract much attention as cathode materials for Na-ion batteries. Indeed, thanks to the inductive effect of the fluoride and phosphate groups, such compounds exhibit a relatively high working potential and good theoretical capacity [1]. In this work, we focus on the iron (Na2FePO4F (NFPF)) and vanadium (Na3V2(PO4)3F3(NVPF)) based fluorophosphate materials which are characterized by a high theoretical capacity of 124 mAh/g and 128 mAh/g, respectively. In addition, the iron-based phase is also more environmental friendly due to the low toxicity of the iron. The preparation of such complex phases using conventional solid-state route requires at least two steps with long heat treatment durations. Here, we report a facile aqueous synthesis using the spray-drying method that can be used for both NFPF and NVPF materials and that can be tuned in order to optimize the composition and the morphology of the desired materials. The major limitation of phosphate-based electrodes is their low intrinsic electronic conductivity. The synthesis of composites with carbon is an effective strategy for the enhancement of the electronic conductivity of these compounds. Spray-drying is a suitable method to incorporate carbon in composite compounds due to the high homogeneity of the obtained particle [2]. It is also a cost effective and up-scalable technique which can produce large quantities of the desired material. Here, we report the influence of the carbon addition of the structural, morphological and electrochemical properties of NFPF and NVPF compounds. The prepared composite materials were investigated by combining several characterisation techniques such as XRD, SEM and TEM. The electrochemical properties were evaluated by galvanostatic cycling and electrochemical impedance spectroscopy in Na-ion batteries. [1] Eshraghi, N., Caes, S., Mahmoud, A., Cloots, R., Vertruyen, B., & Boschini, F. (2017). Sodium vanadium (III) fluorophosphate/carbon nanotubes composite (NVPF/CNT) prepared by spray-drying: good electrochemical performance thanks to well-dispersed CNT network within NVPF particles. Electrochimica Acta, 228, 319-324. [2]Vertruyen, B., Eshraghi, N., Piffet, C., Bodart, J., Mahmoud, A., & Boschini, F. (2018). Spray-Drying of Electrode Materials for Lithium-and Sodium-Ion Batteries. Materials, 11(7), 1076.

Li 4 Ti 5 O 12 /C composite anode materials have been prepared by solid-state reactions using lit... more Li 4 Ti 5 O 12 /C composite anode materials have been prepared by solid-state reactions using lithiumor titanium-containing reagents (lithium lactate, acetate, and acetylacetonate or titanium oxyacetylacetonate) not only as precursors for the synthesis of lithium titanate but also as carbon sources. In addition, two surfactants, Pluronic 123 (P123) and cetyltrimethylammonium bromide, have been used as carbon sources. The composites have been characterized by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy, and their electrochemical properties have been studied. The results demonstrate that the best electrochemical performance is offered by the materials prepared using P123. In particular, the discharge capacity of the Li 4 Ti 5 O 12 /C material prepared using TiO 2 /P123 and lithium lactate is 119 and 44 mAh/g at current densities of 200 and 3200 mA/g, respectively. The materials prepared using lithium and titanium acetylacetonates have high carbon content and undergo more severe degradation during cycling at high current densities.

Li-ion batteries are well-developed for numerous applications but the limited resources and expen... more Li-ion batteries are well-developed for numerous applications but the limited resources and expensive price of lithium urge the necessity to find a viable alternative to lithium. Na-ion batteries are considered as a good alternative to Li-ion batteries due to the abundance and well-distributed presence of sodium on earth crust. It is then necessary to develop new electrode material for sodium batteries, with low cost, high energy density and long cycling life. This work presents the synthesis of Na2FePO4F by spray-drying method. In order to compensate the low conductivity of phosphate based materials, carbon nanotubes (CNT) are added during the preparation of the precursor solution. The solution/suspension is spray-dried to obtain a composite precursor and after calcination the desired phase. The spray-drying technique is appropriate to variate the morphology and to control it by modifying the injection parameters (Pressure, temperature, flow rate, injection nozzle). The addition of carbon nanotubes lead to an undesired reduction of the iron to the metallic state. To resolve this problem, the concentration of carbon was modified until no metallic iron remained in the composition. In the present work, two methodology of injection are compared to study their influence on the phase purity, size and morphology of the particles as well as their electrochemical properties. X-ray diffraction is used to verify the crystallinity and the purity of the phase obtained. The results show that a pure phase is obtained in optimized condition and samples with low amount of impurities like Fe2O3 are obianed when no optimization is done. The oxidation state of Fe in the samples, the nature of the impurities and the quantities are confirmed by Mossbauer spectroscopy. During calcination, we observed a phenomenon of carbothermal reduction which was evidenced by Mossbauer spectroscopy (Figure 1). SEM analysis shows the morphology of the obtained particles with a size range between 1,5 m and 8 m using bi-fluid and rotary nozzles, respectively. The electrochemical performances are tested by galvanostatic cycling in sodium half cells and show significant improvement with the optimization of morphology and carbon content

The goal of this works is minimized post-treatment of batteries material synthesis, as grinding o... more The goal of this works is minimized post-treatment of batteries material synthesis, as grinding or carbon addition. We have add during synthesis carbon nanotubes to enhance the conductivity of the phosphate based material Na2FePO4F. This addition of carbon induce a modifications of the cristallisation and lead to impureties. By modifying the attack of iron(0) and adapting the heat treatment we have enhance the purity of the material. We have also compare the influence of the injection mode on the size which is drastically reduce (8micron to 1.5micron); on the electrochemical performance ( 110mAh/g for rotative nozzle, 140mAh/g for the bifluid) and on the oxidation state of the iron in the product analysed by mossbauer spectroscopy (16% of Fe(III) with rotative nozzle; 12% of Fe(III) with the bifluid nozzle)

Na2Ti3O7 is considered as a promising intercalation anode material for sodium ion batteries thank... more Na2Ti3O7 is considered as a promising intercalation anode material for sodium ion batteries thanks to its low insertion potential (0.3V vs Na0/Na+) and relatively good theoretical capacity (178 mAh/g) [1,2,3]. Nevertheless, it has a poor long term cycling stability that still needs to be solved. Besides, the importance of the choice of the electrolyte for Na-ion batteries was recently reviewed [4]. We report here a new spray-drying synthesis of Na2Ti3O7. By contrast to the solid-state synthesis, the advantages of the spray-drying method are a high homogeneity of the precursors and good control of the particle size and morphology (typically spherical particles of 3-30 µm, depending on the injection mode, concentration, pressure, temperature, etc.). Therefore, the heat treatment time is decreased. In this work, we studied the formation mechanism of Na2Ti3O7. We identified sequences of intermediate phases, starting from spray-dried TiO2 and NaOH or Na2CO3 precursors. In order to improve the performances of our material, we also tested the influence of the electrolyte on the electrochemical performances in half cell. The effect of the solvent (PC, EC, DMC and Diglyme) but also of the salt (NaClO4, NaPF6, NaTFSI, NaFSI and NaOTf) was examined and significant differences were observed. [1] Zukalová et al., Journal of Solid State Electrochemistry, 2018, 22, 2545–2552 [2] J. Nava-Avendaño et al., Journal of Material Chemistry A, 2015, 3, 22280-22286 [3] M. Zarrabeitia et al., Acta Materialia, 2016, 104, 125-130 [4] A. Ponrouch et al., Journal of Material Chemistry A, 2015, 3, 22-4

Fluorophosphates are considered among the most interesting series of cathode material for Li/Na-i... more Fluorophosphates are considered among the most interesting series of cathode material for Li/Na-ion batteries1. Na2FePO4F (space group Pbcn), with its layered structure and two-dimensional pathways for facile Na+/Li+ transport, exhibits minimal structural changes upon reduction/oxidation. The average working voltage is 3.3 V vs. Li/Li+. Intercalation/deintercalation results in a volume change of only 3.7%. However, one of the key drawbacks of Na2FePO4F electrodes is their low intrinsic electronic conductivity. In order to study the effect of the carbon black and carbon nanotubes on the electrochemical performance of Na2FePO4F cathode material for lithium-ion batteries, Na2FePO4F, Na2FePO4F/CB and Na2FePO4F/CNT were prepared by a spray-drying method with different ratios of CB and CNT (10 and 20%). The crystal and local structure were analyzed by XRD and Mössbauer spectroscopy. The electrochemical properties were studied by galvanostatic cycling in lithium cells. The electrochemical performance is markedly better in the case of Na2FePO4F/CNT (20 wt%), with specific capacities of about 100 mAh/g (Na2FePO4F/CNT) at C/4 rate2 vs. 50 mAh/g for Na2FePO4F/CB. The characterization of Na2FePO4F/CB particles by electron microscopy revealed a carbon-poor surface and a good carbon dispersion for Na2FePO4F/CNT particles attributed to better diffusion of carbon nanotubes in the droplets during drying. References : 1-N. Eshraghi, S. Caes, A. Mahmoud, R. Cloots, B. Vertruyen, F. Boschini, Electrochim. Acta, 228 (2017) 319–324. 2-M. Brisbois, S. Caes, M-T. Sougrati, B. Vertruyen, A. Schrijnemakers, R. Cloots, N. Eshraghi, R-P. Hermann, A. Mahmoud, F. Boschini, Solar Energy Materials & Solar Cells 148 (2015) 67-72

Journal of The European Ceramic Society, Aug 1, 2005

In this article, the colloidal behaviour of aqueous suspensions of barium zirconate is investigat... more In this article, the colloidal behaviour of aqueous suspensions of barium zirconate is investigated. The variation of ζ-potential as a consequence of changing the pH and the concentration of an anionic polyelectrolyte is studied, the isoelectric point occurring at pH 5.3. The IEP shifts down on calcining the powder and also when anionic polyelectrolytes are added. Rheological studies have been made on suspensions prepared to a solids loading of 27 vol.% (72 wt.%). Optimum dispersing conditions are reached for suspensions prepared at basic pH with 1.5 wt.% tetramethylammonium hydroxide (TMAH) and a concentration of ammonium polymethacrylate (PMAA) of 1.6 wt.%. Comparison with similar suspensions prepared with NaOH instead PMAA demonstrated that TMAH gives an extra contribution to stability, probably related to the adsorption of N + (Me) 4 groups. The suspensions were slip cast, and green densities higher than 60% of theoretical were obtained.

The growing interest in Na-ion batteries as a “beyond lithium” technologies for energy storage dr... more The growing interest in Na-ion batteries as a “beyond lithium” technologies for energy storage drives the research for high-performance and environment-friendly materials. Na2Ti3O7 (NTO) as an eco-friendly, low-cost anode material shows a very low working potential of 0.3 V vs Na+/Na but suffers from poor cycling stability, which properties can be significantly influenced by materials synthesis and treatment. Thus, in this work, the influence of the calcination time on the electrochemical performance and the reaction mechanism during cycling were investigated. NTO heat-treated for 48 h at 800 °C (NTO-48h) demonstrated enhanced cycling performance in comparison to NTO heat-treated for only 8 h (NTO-8h). The pristine material was thoroughully characterized by X-ray diffraction, laser granulometry, X-ray photoelectron spectroscopy, and specific surface area measurements. The reaction mechanisms induced by sodiation/desodiation and cycling were investigated by opernado XRD. Electrochemical impedance spectroscopy was used to evidence the evolution of the solid electrolyte interface layer (SEI) and modification of charge transfer resistances as well as the influence of cycling on capacity decay. The evolution of the crystallographic structure of NTO-48h revealed a more ordered structure and lower surface contamination compared to NTO-8h. Moreover, the residual Na4Ti3O7 phase detected after the sodium extraction step in NTO-8h seems correlated to the lower electrochemical performance of NTO-8h compared to NTO-48h.

Batteries & supercaps, Nov 18, 2020

Supporting information for this article is given via a link at the end of the document.

Journal of Superconductivity and Novel Magnetism, May 9, 2020

This work is devoted to investigating the magnetic and magnetocaloric properties of La 0.45 Nd 0.... more This work is devoted to investigating the magnetic and magnetocaloric properties of La 0.45 Nd 0.25 Sr 0.3 MnO 3-CuO composite prepared by the solid-state reaction with various concentration of CuO (2 wt.%, 5 wt.%, and 10 wt.%). The X-ray diffraction (XRD) and the scanning electron microscopy (SEM) techniques were used to identify the obtained structural phases and microstructural morphologies in the prepared pellets. A second-order transition was observed with critical a temperature around 294 K for 2 wt.% and 10 wt.% and 321 K for 5 wt.% of the CuO phase in the composite. Magnetic entropy changes in La 0.45 Nd 0.25 Sr 0.3 MnO 3-CuO composites were calculated using the Maxwell approximation around the magnetic transition. The highest values of magnetic entropy change were found for 5 wt.% of CuO in La 0.45 Nd 0.25 Sr 0.3 MnO 3-CuO pellet composites which is attributed to the localization of the copper oxide in the grains boundaries of La 0.45 Nd 0.25 Sr 0.3 MnO 3 perovskite.

Dry Powder Inhaler (DPI) are used for the treatment of pulmonary diseases. They are based on a mi... more Dry Powder Inhaler (DPI) are used for the treatment of pulmonary diseases. They are based on a mix of drug and excipient that is inhaled by patients. The excipient transports the drug (budesonide) to the respiratory tracts. In order to optimize this deposition, the budesonide particles should have a spherical morphology and a size between 1 to 5 µm. Sonocrystallization is the technique used to design this drug. Using experimental design, we were able to highlight the influence of several parameters on the size and morphology of budesonide particles

Electrochimica Acta, 2017

RSC Advances, 2019

Li 2 M(WO 4) 2 (M ¼ Co, Cu or Ni) materials have been synthesized using the solid-state reaction ... more Li 2 M(WO 4) 2 (M ¼ Co, Cu or Ni) materials have been synthesized using the solid-state reaction method. X-ray diffraction measurements confirmed the single phase of the synthesized compounds in the triclinic crystal system (space group P 1). The SEM analyses revealed nearly spherical morphology with the particle size in the range of 1-10 mm. The IR spectra confirm the presence of all modes of WO 4 2À. The impedance spectroscopy measurements showed the presence of grain boundaries and allow determination of the conductivity of the synthesized materials at room temperature. As positive electrode materials for lithium ion batteries, Li 2 M(WO 4) 2 (M ¼ Co, Cu or Ni) cathode materials deliver initial discharge capacities of 31, 33 and 30 mA h g À1 for cobalt, nickel, and copper, respectively.

International Journal of Pharmaceutics, Oct 1, 2015

The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been... more The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been analyzed with three recently improved measurement methods. The first method is based on the heap shape measurement. This straightforward measurement method provides two physical parameters (angle of repose αr and static cohesive index σr) allowing to make a first screening of the powder properties. The second method allows to estimate the rheological properties of a powder by analyzing the powder flow in a rotating drum. This more advanced method gives a large set of physical parameters (flowing angle αf, dynamic cohesive index σf, angle of first avalanche αa and powder aeration %ae) leading to deeper interpretations. The third method is an improvement of the classical bulk and tapped density measurements. In addition to the improvement of the measurement precision, the densification dynamics of the powder bulk submitted to taps is analyzed. The link between the macroscopic physical parameters obtained with these methods and the powder granulometry is analyzed. Moreover, the correlations between the different flowability indexes are discussed. Finally, the link between grain shape and flowability is discussed qualitatively.

Journal of Photochemistry and Photobiology A-chemistry, Oct 1, 2016

Towards a large scale aqueous sol-gel synthesis of doped TiO 2 : Study of various metallic doping... more Towards a large scale aqueous sol-gel synthesis of doped TiO 2 : Study of various metallic dopings for the photocatalytic degradation of p-nitrophenol

Reaction Kinetics, Mechanisms and Catalysis, Jun 1, 2023

Materials, Dec 21, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Meeting abstracts, 2019

Fluorophosphate compounds attract much attention as cathode materials for Na-ion batteries. Indee... more Fluorophosphate compounds attract much attention as cathode materials for Na-ion batteries. Indeed, thanks to the inductive effect of the fluoride and phosphate groups, such compounds exhibit a relatively high working potential and good theoretical capacity [1]. In this work, we focus on the iron (Na2FePO4F (NFPF)) and vanadium (Na3V2(PO4)3F3(NVPF)) based fluorophosphate materials which are characterized by a high theoretical capacity of 124 mAh/g and 128 mAh/g, respectively. In addition, the iron-based phase is also more environmental friendly due to the low toxicity of the iron. The preparation of such complex phases using conventional solid-state route requires at least two steps with long heat treatment durations. Here, we report a facile aqueous synthesis using the spray-drying method that can be used for both NFPF and NVPF materials and that can be tuned in order to optimize the composition and the morphology of the desired materials. The major limitation of phosphate-based electrodes is their low intrinsic electronic conductivity. The synthesis of composites with carbon is an effective strategy for the enhancement of the electronic conductivity of these compounds. Spray-drying is a suitable method to incorporate carbon in composite compounds due to the high homogeneity of the obtained particle [2]. It is also a cost effective and up-scalable technique which can produce large quantities of the desired material. Here, we report the influence of the carbon addition of the structural, morphological and electrochemical properties of NFPF and NVPF compounds. The prepared composite materials were investigated by combining several characterisation techniques such as XRD, SEM and TEM. The electrochemical properties were evaluated by galvanostatic cycling and electrochemical impedance spectroscopy in Na-ion batteries. [1] Eshraghi, N., Caes, S., Mahmoud, A., Cloots, R., Vertruyen, B., & Boschini, F. (2017). Sodium vanadium (III) fluorophosphate/carbon nanotubes composite (NVPF/CNT) prepared by spray-drying: good electrochemical performance thanks to well-dispersed CNT network within NVPF particles. Electrochimica Acta, 228, 319-324. [2]Vertruyen, B., Eshraghi, N., Piffet, C., Bodart, J., Mahmoud, A., & Boschini, F. (2018). Spray-Drying of Electrode Materials for Lithium-and Sodium-Ion Batteries. Materials, 11(7), 1076.

Li 4 Ti 5 O 12 /C composite anode materials have been prepared by solid-state reactions using lit... more Li 4 Ti 5 O 12 /C composite anode materials have been prepared by solid-state reactions using lithiumor titanium-containing reagents (lithium lactate, acetate, and acetylacetonate or titanium oxyacetylacetonate) not only as precursors for the synthesis of lithium titanate but also as carbon sources. In addition, two surfactants, Pluronic 123 (P123) and cetyltrimethylammonium bromide, have been used as carbon sources. The composites have been characterized by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy, and their electrochemical properties have been studied. The results demonstrate that the best electrochemical performance is offered by the materials prepared using P123. In particular, the discharge capacity of the Li 4 Ti 5 O 12 /C material prepared using TiO 2 /P123 and lithium lactate is 119 and 44 mAh/g at current densities of 200 and 3200 mA/g, respectively. The materials prepared using lithium and titanium acetylacetonates have high carbon content and undergo more severe degradation during cycling at high current densities.

Li-ion batteries are well-developed for numerous applications but the limited resources and expen... more Li-ion batteries are well-developed for numerous applications but the limited resources and expensive price of lithium urge the necessity to find a viable alternative to lithium. Na-ion batteries are considered as a good alternative to Li-ion batteries due to the abundance and well-distributed presence of sodium on earth crust. It is then necessary to develop new electrode material for sodium batteries, with low cost, high energy density and long cycling life. This work presents the synthesis of Na2FePO4F by spray-drying method. In order to compensate the low conductivity of phosphate based materials, carbon nanotubes (CNT) are added during the preparation of the precursor solution. The solution/suspension is spray-dried to obtain a composite precursor and after calcination the desired phase. The spray-drying technique is appropriate to variate the morphology and to control it by modifying the injection parameters (Pressure, temperature, flow rate, injection nozzle). The addition of carbon nanotubes lead to an undesired reduction of the iron to the metallic state. To resolve this problem, the concentration of carbon was modified until no metallic iron remained in the composition. In the present work, two methodology of injection are compared to study their influence on the phase purity, size and morphology of the particles as well as their electrochemical properties. X-ray diffraction is used to verify the crystallinity and the purity of the phase obtained. The results show that a pure phase is obtained in optimized condition and samples with low amount of impurities like Fe2O3 are obianed when no optimization is done. The oxidation state of Fe in the samples, the nature of the impurities and the quantities are confirmed by Mossbauer spectroscopy. During calcination, we observed a phenomenon of carbothermal reduction which was evidenced by Mossbauer spectroscopy (Figure 1). SEM analysis shows the morphology of the obtained particles with a size range between 1,5 m and 8 m using bi-fluid and rotary nozzles, respectively. The electrochemical performances are tested by galvanostatic cycling in sodium half cells and show significant improvement with the optimization of morphology and carbon content

The goal of this works is minimized post-treatment of batteries material synthesis, as grinding o... more The goal of this works is minimized post-treatment of batteries material synthesis, as grinding or carbon addition. We have add during synthesis carbon nanotubes to enhance the conductivity of the phosphate based material Na2FePO4F. This addition of carbon induce a modifications of the cristallisation and lead to impureties. By modifying the attack of iron(0) and adapting the heat treatment we have enhance the purity of the material. We have also compare the influence of the injection mode on the size which is drastically reduce (8micron to 1.5micron); on the electrochemical performance ( 110mAh/g for rotative nozzle, 140mAh/g for the bifluid) and on the oxidation state of the iron in the product analysed by mossbauer spectroscopy (16% of Fe(III) with rotative nozzle; 12% of Fe(III) with the bifluid nozzle)

Na2Ti3O7 is considered as a promising intercalation anode material for sodium ion batteries thank... more Na2Ti3O7 is considered as a promising intercalation anode material for sodium ion batteries thanks to its low insertion potential (0.3V vs Na0/Na+) and relatively good theoretical capacity (178 mAh/g) [1,2,3]. Nevertheless, it has a poor long term cycling stability that still needs to be solved. Besides, the importance of the choice of the electrolyte for Na-ion batteries was recently reviewed [4]. We report here a new spray-drying synthesis of Na2Ti3O7. By contrast to the solid-state synthesis, the advantages of the spray-drying method are a high homogeneity of the precursors and good control of the particle size and morphology (typically spherical particles of 3-30 µm, depending on the injection mode, concentration, pressure, temperature, etc.). Therefore, the heat treatment time is decreased. In this work, we studied the formation mechanism of Na2Ti3O7. We identified sequences of intermediate phases, starting from spray-dried TiO2 and NaOH or Na2CO3 precursors. In order to improve the performances of our material, we also tested the influence of the electrolyte on the electrochemical performances in half cell. The effect of the solvent (PC, EC, DMC and Diglyme) but also of the salt (NaClO4, NaPF6, NaTFSI, NaFSI and NaOTf) was examined and significant differences were observed. [1] Zukalová et al., Journal of Solid State Electrochemistry, 2018, 22, 2545–2552 [2] J. Nava-Avendaño et al., Journal of Material Chemistry A, 2015, 3, 22280-22286 [3] M. Zarrabeitia et al., Acta Materialia, 2016, 104, 125-130 [4] A. Ponrouch et al., Journal of Material Chemistry A, 2015, 3, 22-4

Fluorophosphates are considered among the most interesting series of cathode material for Li/Na-i... more Fluorophosphates are considered among the most interesting series of cathode material for Li/Na-ion batteries1. Na2FePO4F (space group Pbcn), with its layered structure and two-dimensional pathways for facile Na+/Li+ transport, exhibits minimal structural changes upon reduction/oxidation. The average working voltage is 3.3 V vs. Li/Li+. Intercalation/deintercalation results in a volume change of only 3.7%. However, one of the key drawbacks of Na2FePO4F electrodes is their low intrinsic electronic conductivity. In order to study the effect of the carbon black and carbon nanotubes on the electrochemical performance of Na2FePO4F cathode material for lithium-ion batteries, Na2FePO4F, Na2FePO4F/CB and Na2FePO4F/CNT were prepared by a spray-drying method with different ratios of CB and CNT (10 and 20%). The crystal and local structure were analyzed by XRD and Mössbauer spectroscopy. The electrochemical properties were studied by galvanostatic cycling in lithium cells. The electrochemical performance is markedly better in the case of Na2FePO4F/CNT (20 wt%), with specific capacities of about 100 mAh/g (Na2FePO4F/CNT) at C/4 rate2 vs. 50 mAh/g for Na2FePO4F/CB. The characterization of Na2FePO4F/CB particles by electron microscopy revealed a carbon-poor surface and a good carbon dispersion for Na2FePO4F/CNT particles attributed to better diffusion of carbon nanotubes in the droplets during drying. References : 1-N. Eshraghi, S. Caes, A. Mahmoud, R. Cloots, B. Vertruyen, F. Boschini, Electrochim. Acta, 228 (2017) 319–324. 2-M. Brisbois, S. Caes, M-T. Sougrati, B. Vertruyen, A. Schrijnemakers, R. Cloots, N. Eshraghi, R-P. Hermann, A. Mahmoud, F. Boschini, Solar Energy Materials & Solar Cells 148 (2015) 67-72

Journal of The European Ceramic Society, Aug 1, 2005

In this article, the colloidal behaviour of aqueous suspensions of barium zirconate is investigat... more In this article, the colloidal behaviour of aqueous suspensions of barium zirconate is investigated. The variation of ζ-potential as a consequence of changing the pH and the concentration of an anionic polyelectrolyte is studied, the isoelectric point occurring at pH 5.3. The IEP shifts down on calcining the powder and also when anionic polyelectrolytes are added. Rheological studies have been made on suspensions prepared to a solids loading of 27 vol.% (72 wt.%). Optimum dispersing conditions are reached for suspensions prepared at basic pH with 1.5 wt.% tetramethylammonium hydroxide (TMAH) and a concentration of ammonium polymethacrylate (PMAA) of 1.6 wt.%. Comparison with similar suspensions prepared with NaOH instead PMAA demonstrated that TMAH gives an extra contribution to stability, probably related to the adsorption of N + (Me) 4 groups. The suspensions were slip cast, and green densities higher than 60% of theoretical were obtained.

The growing interest in Na-ion batteries as a “beyond lithium” technologies for energy storage dr... more The growing interest in Na-ion batteries as a “beyond lithium” technologies for energy storage drives the research for high-performance and environment-friendly materials. Na2Ti3O7 (NTO) as an eco-friendly, low-cost anode material shows a very low working potential of 0.3 V vs Na+/Na but suffers from poor cycling stability, which properties can be significantly influenced by materials synthesis and treatment. Thus, in this work, the influence of the calcination time on the electrochemical performance and the reaction mechanism during cycling were investigated. NTO heat-treated for 48 h at 800 °C (NTO-48h) demonstrated enhanced cycling performance in comparison to NTO heat-treated for only 8 h (NTO-8h). The pristine material was thoroughully characterized by X-ray diffraction, laser granulometry, X-ray photoelectron spectroscopy, and specific surface area measurements. The reaction mechanisms induced by sodiation/desodiation and cycling were investigated by opernado XRD. Electrochemical impedance spectroscopy was used to evidence the evolution of the solid electrolyte interface layer (SEI) and modification of charge transfer resistances as well as the influence of cycling on capacity decay. The evolution of the crystallographic structure of NTO-48h revealed a more ordered structure and lower surface contamination compared to NTO-8h. Moreover, the residual Na4Ti3O7 phase detected after the sodium extraction step in NTO-8h seems correlated to the lower electrochemical performance of NTO-8h compared to NTO-48h.

Batteries & supercaps, Nov 18, 2020

Supporting information for this article is given via a link at the end of the document.

Journal of Superconductivity and Novel Magnetism, May 9, 2020

This work is devoted to investigating the magnetic and magnetocaloric properties of La 0.45 Nd 0.... more This work is devoted to investigating the magnetic and magnetocaloric properties of La 0.45 Nd 0.25 Sr 0.3 MnO 3-CuO composite prepared by the solid-state reaction with various concentration of CuO (2 wt.%, 5 wt.%, and 10 wt.%). The X-ray diffraction (XRD) and the scanning electron microscopy (SEM) techniques were used to identify the obtained structural phases and microstructural morphologies in the prepared pellets. A second-order transition was observed with critical a temperature around 294 K for 2 wt.% and 10 wt.% and 321 K for 5 wt.% of the CuO phase in the composite. Magnetic entropy changes in La 0.45 Nd 0.25 Sr 0.3 MnO 3-CuO composites were calculated using the Maxwell approximation around the magnetic transition. The highest values of magnetic entropy change were found for 5 wt.% of CuO in La 0.45 Nd 0.25 Sr 0.3 MnO 3-CuO pellet composites which is attributed to the localization of the copper oxide in the grains boundaries of La 0.45 Nd 0.25 Sr 0.3 MnO 3 perovskite.

Dry Powder Inhaler (DPI) are used for the treatment of pulmonary diseases. They are based on a mi... more Dry Powder Inhaler (DPI) are used for the treatment of pulmonary diseases. They are based on a mix of drug and excipient that is inhaled by patients. The excipient transports the drug (budesonide) to the respiratory tracts. In order to optimize this deposition, the budesonide particles should have a spherical morphology and a size between 1 to 5 µm. Sonocrystallization is the technique used to design this drug. Using experimental design, we were able to highlight the influence of several parameters on the size and morphology of budesonide particles

Electrochimica Acta, 2017

RSC Advances, 2019

Li 2 M(WO 4) 2 (M ¼ Co, Cu or Ni) materials have been synthesized using the solid-state reaction ... more Li 2 M(WO 4) 2 (M ¼ Co, Cu or Ni) materials have been synthesized using the solid-state reaction method. X-ray diffraction measurements confirmed the single phase of the synthesized compounds in the triclinic crystal system (space group P 1). The SEM analyses revealed nearly spherical morphology with the particle size in the range of 1-10 mm. The IR spectra confirm the presence of all modes of WO 4 2À. The impedance spectroscopy measurements showed the presence of grain boundaries and allow determination of the conductivity of the synthesized materials at room temperature. As positive electrode materials for lithium ion batteries, Li 2 M(WO 4) 2 (M ¼ Co, Cu or Ni) cathode materials deliver initial discharge capacities of 31, 33 and 30 mA h g À1 for cobalt, nickel, and copper, respectively.

International Journal of Pharmaceutics, Oct 1, 2015

The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been... more The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been analyzed with three recently improved measurement methods. The first method is based on the heap shape measurement. This straightforward measurement method provides two physical parameters (angle of repose αr and static cohesive index σr) allowing to make a first screening of the powder properties. The second method allows to estimate the rheological properties of a powder by analyzing the powder flow in a rotating drum. This more advanced method gives a large set of physical parameters (flowing angle αf, dynamic cohesive index σf, angle of first avalanche αa and powder aeration %ae) leading to deeper interpretations. The third method is an improvement of the classical bulk and tapped density measurements. In addition to the improvement of the measurement precision, the densification dynamics of the powder bulk submitted to taps is analyzed. The link between the macroscopic physical parameters obtained with these methods and the powder granulometry is analyzed. Moreover, the correlations between the different flowability indexes are discussed. Finally, the link between grain shape and flowability is discussed qualitatively.

Journal of Photochemistry and Photobiology A-chemistry, Oct 1, 2016

Towards a large scale aqueous sol-gel synthesis of doped TiO 2 : Study of various metallic doping... more Towards a large scale aqueous sol-gel synthesis of doped TiO 2 : Study of various metallic dopings for the photocatalytic degradation of p-nitrophenol

Reaction Kinetics, Mechanisms and Catalysis, Jun 1, 2023

Materials, Dec 21, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY