References of "Vertruyen, Bénédicte"
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See detailSodium vanadium (III) fluorophosphate/carbon nanotubes composite (NVPF/CNT) prepared by spray-drying: good electrochemical performance thanks to well-dispersed CNT network within NVPF particles
Eshraghi, Nicolas ULg; Caes, Sebastien; Mahmoud, Abdelfattah ULg et al

in Electrochimica Acta (2017), 228

We successfully prepared NASICON-type Na3V2(PO4)2F3 (NVPF) and a Na3V2(PO4)2F3/carbon nanotubes (CNT) composite by spray-drying followed by heat treatment in argon for 2 hours at 600 °C. The addition of ... [more ▼]

We successfully prepared NASICON-type Na3V2(PO4)2F3 (NVPF) and a Na3V2(PO4)2F3/carbon nanotubes (CNT) composite by spray-drying followed by heat treatment in argon for 2 hours at 600 °C. The addition of CNT in the spray-drying solution creates a CNT network within the NVPF particles. After grinding, the smaller NVPF particles remain linked by CNT. Thanks to this conducting network, the composite powder displays competitive electrochemical performance when cycled against lithium in hybrid-ion batteries (2–4.6 V vs. Li+/Li) with specific capacities of 125 mAh.g−1 at C/10, 103 mAh.g−1 at 1C and 91 mAh.g−1 at 4C, together with 97.5% capacity retention at 1C over 100 cycles with coulombic efficiency of 99.4%. These results demonstrate that sodium vanadium (III) fluorophosphate electrode material can be obtained in a time-efficient way using the easily up-scalable spray-drying method. [less ▲]

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See detailComparison of Indium Tin Oxide and Indium Tungsten Oxide as Transparent Conductive Substrates for WO3-Based Electrochromic Devices
Maho, Anthony ULg; Nicolay, Sylvain; Manceriu, Laura ULg et al

in Journal of the Electrochemical Society (2017), 164(2), 25-31

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See detailPolyhydroxyurethane hydrogels: synthesis and characterizations
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

in European Polymer Journal (2016), 84

Hydrogels based on polyurethane (PU) are promising (bio-) materials because of their bio- compatibility, biodegradation and excellent mechanical properties. In this publication, polyurethane hydrogels ... [more ▼]

Hydrogels based on polyurethane (PU) are promising (bio-) materials because of their bio- compatibility, biodegradation and excellent mechanical properties. In this publication, polyurethane hydrogels were produced for the first time by a non-isocyanate route by solvent-free step-growth copolymerization between a CO2-sourced hydrophilic polyethy- lene glycol bi-cyclic carbonate with diamines in the presence of a cross-linker. Kinetic of poly(hydroxyurethane) (PHU) synthesis was monitored by ATR-IR and the chemical cross-linking was confirmed by rheology and gel contents measurements. Hydrogels were obtained by immersion of PHUs in water and the influence of the diamine/cross-linker ratio and the nature of diamine on the water swelling and compression properties (compression modulus, strain and stress at break) of PHU hydrogels was evaluated. Additionally, the compression properties of the hydrogels were improved by the addition of Montmorillonite as nanofiller in the PHU formulation. This work opens new application fields for CO2-sourced PHUs. [less ▲]

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See detailDesign and synthesis of Fe2O3 nanoparticles/N-doped porous carbon structures as high performance electrode for lithium ion battery
Alkarmo, Walid ULg; Ouhib, Farid ULg; Aqil, Abdelhafid ULg et al

Poster (2016, October 13)

Thanks to their fascinating physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, three dimensionally (3D) interconnected carbon porous ... [more ▼]

Thanks to their fascinating physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, three dimensionally (3D) interconnected carbon porous frameworks have emerged as attractive materials for various electrochemical energy storage/conversion devices, including Li-ion batteries (LIBs), Li−S batteries, supercapacitors and fuel cells. In this context, a hierarchically structured macro- and mesoporous N-doped carbon with dispersed Fe2O3 nanoparticles (NDC@Fe2O3) is prepared by thermal treatment of a novel composite composed by PMMA particles decorated by graphene oxide (GO), PPy and iron salts. The NDC@Fe2O3 composite exhibited high surface area with a hierarchical pores structure. The combination of Fe2O3 nanoparticles with porous carbon to form hybrid anode has been an efficient way to maintain the electronic integrity of the whole electrode since the carbon acts as a buffer layer to accommodate the volume variation and to provide multidimensional electron transport pathways during the charge/discharge process. [less ▲]

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See detailSynthesis and characterization of non-isocyanate polyurethane (NIPU) hydrogels
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, October 13)

Due to its good biocompatibility, biodegradation and excellent mechanical properties, polyurethane (PU) is a material of choice for biomedical applications (gloves, tubing, artificial membranes…) and, as ... [more ▼]

Due to its good biocompatibility, biodegradation and excellent mechanical properties, polyurethane (PU) is a material of choice for biomedical applications (gloves, tubing, artificial membranes…) and, as hydrogels, it was used as wound dressing, soft contact lenses, drug delivery systems and scaffolds for tissue engineering. Classically, PU are synthesized by a step-growth polymerization between poly (di-)ols and poly (di-) isocyanates. Due to the toxicity of isocyanates, REACH regulations have changed and, today, there is a need to develop greener and safer route to produce isocyanate-free PUs. This contribution focus on the synthesis of NIPU hydrogels by copolymerizing a bifunctional CO2-sourced hydrophilic PEG bi-cyclic carbonate with diamines in presence of a cross- linker. The PEG bi-cyclic carbonates was prepared via a CO2/epoxide coupling reactions using a new efficient organocatalytic system based on the use of an ammonium salt (TBAI) in combination with a fluorinated alcohol. [less ▲]

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See detailMOSSBAUER SPECTROSCOPY AS A COMPLEMENTARY TECHNIQUE OF X-RAY DIFFRACTION TO INVESTIGATE ELECTRODE MATERIALS FOR ALKALI-ION BATTERIES
Mahmoud, Abdelfattah ULg; sougrati, Moulay Tahar; karegeya, claude et al

Poster (2016, October 09)

Lithium-ion batteries (LIBs) have been widely applied as a power source for portable electronics, stationary energy storage systems, and electric vehicles. Nevertheless, as lithium resources continue to ... [more ▼]

Lithium-ion batteries (LIBs) have been widely applied as a power source for portable electronics, stationary energy storage systems, and electric vehicles. Nevertheless, as lithium resources continue to decline worldwide and Li in the Earth’s crust is unevenly distributed as minor-metal. Na-ion batteries are considered to be an alternative to Li-ion batteries owing to the natural abundance of sodium. Indeed, Sodium-ion (Na-ion) batteries are expected to become part of the mix of technologies that will meet the challenges of energy storage. Electrode materials are the most important components in the operation and the performances of Alkali-ion batteries. New electrode materials are required to increase the energy density of Li/Na-ion batteries [1]. Fe based negative electrode materials for Li-ion batteries have been previously investigated to evaluate the electrochemical performances and elucidate the electrochemical reaction mechanisms. Mössbauer spectroscopy has been applied to a variety of fields including chemistry, physics, geology, biology…. In the domain of energy storage, Mössbauer spectroscopy has been used as a powerful tool to investigate the local electronic and structural properties of electrode materials and to determine their reaction mechanisms during charge and discharge of Li/Na-ion batteries [2]. In this poster, we will show from some selected examples how Mössbauer spectroscopy when used with X-ray diffraction can help to improve the performances of electrode materials for Alkali-ion batteries. References 1. Sougrati MT, Darwiche A, Liu X, Mahmoud A, Hermann RP, Jouen S, Monconduit L, Dronskowski R, Stievano L: Transition-metal carbodiimides as molecular negative electrode materials for lithium- and sodium-ion batteries with excellent cycling properties. Angew Chem Int Ed., 2016, 55: 5090-5095. 2. Brisbois, M., Caes, S., Sougrati, M. T., Vertruyen, B., Schrijnemakers, A., Cloots, R., Eshraghi, N., Hermann, R. P., Mahmoud, A., Boschini, F. Na2FePO4F/Multi-Walled Carbon Nanotubes for Lithium-Ion Batteries_ Operando Mössbauer Study of Spray- Dried Composites. Solar Energy Materials and Solar Cells 2016, 148, 67–72. Acknowledgment A. Mahmoud and F. Boschini would like to kindly thank Wallonie regions for the financial support. [less ▲]

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See detailPhosphate-based composite electrodes for Li/Na-ion batteries: upscalable solution syntheses with in-situ solid carbon addition
Vertruyen, Bénédicte ULg; Brisbois, Magali; Eshraghi, Nicolas ULg et al

Conference (2016, September 22)

Since the success story of lithium iron phosphate, other phosphate-based compounds have attracted a lot of interest as promising candidates for positive electrodes in lithium-ion or sodium-ion batteries ... [more ▼]

Since the success story of lithium iron phosphate, other phosphate-based compounds have attracted a lot of interest as promising candidates for positive electrodes in lithium-ion or sodium-ion batteries. Their electronic conductivity usually has to be improved through the preparation of composite powders ensuring intimate contact between the active material and conductive carbon. We report on the one-step synthesis of composite precursors using spray-drying or hydrothermal synthesis routes, two techniques which offer easy scaling-up of production. We show that addition of a solid carbon source (carbon black or carbon nanotubes) into the solution has a strong influence on the powder microstructure and is very effective in improving the battery cycling performance, taking our recent results on phosphates [Fex(PO4)(OH)y.zH2O)] and fluorophosphates [Na2FePO4F, Na3V2(PO4)2F3] as examples. We also compare this approach with the addition of the carbon source as a soluble precursor (such as ascorbic acid or citric acid) where the in situ formation of carbon is achieved by a heat treatment in inert atmosphere (typically argon). [less ▲]

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See detailSynthesis and characterizations of non-isocyanate polyurethane (NIPU) hydrogels
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, September 12)

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of ... [more ▼]

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of applications such as wound dressing, soft contact lenses, drug delivery and scaffolds for tissue engineering. Classicaly, PU is produced by a step-growth polymerization between diols and diisocyanates. However, in order to avoid the use of harmful isocyanates compounds and because of regulations which tend to ban the use of isocyanates, we developed hydrogels based on a non-isocyanate polyurethane (NIPU) chemistry by valorizing CO2-sourced cyclic carbonates and amines. Precisely, NIPU hydrogels were prepared by a solvent-free copolymerization between bifunctional hydrophilic polyethylene glycol cyclic carbonates and diamines in presence of a triamine as a crosslinker, followed by a water swelling of the obtained cross-linked gel. Parameters such as the cross-linking ratio and diamine’s nature were optimized. Different clay contents (cloiste 30B) as nanofiller were dispersed in the ideal cyclic carbonate/diamine/triamine formulation prior polymerization in order to reinforce the compression properties of NIPU hydrogels. Finaly, we were able to prepare NIPU hydrogels with water content up to 80 % and good compression properties using low clay content. [less ▲]

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See detailValorization of CO2 for the preparation of advanced materials
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Conference (2016, July 07)

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See detailFe2O3 nanoparticle-functionalized N-doped carbon with interconnected, hierarchical porous structures as high-performance electrode for lithium ion batteries
Alkarmo, Walid ULg; Ouhib, Farid ULg; Aqil, Abdelhafid ULg et al

Poster (2016, May 23)

Thanks to their fascinating physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, three dimensionally (3D) interconnected carbon porous ... [more ▼]

Thanks to their fascinating physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, three dimensionally (3D) interconnected carbon porous frameworks have emerged as attractive materials for various electrochemical energy storage/conversion devices, including Li-ion batteries (LIBs), Li−O2 batteries, Li−S batteries, supercapacitors, and fuel cells. A hierarchically structured macro- and mesoporous N-doped carbon with dispersed Fe2O3 nanoparticles (NDC@Fe2O3) is prepared by thermal treatment of a novel composite composed by PMMA particles decorated by graphene oxide (GO), PPy and iron salts. The NDC@Fe2O3 composite exhibited high surface area with a hierarchical pores structure. Integrated as a lithium ion battery anode, NDC@Fe2O3 exhibited high reversible capacity of 930 mA h/g over 200 cycles. The combination of Fe2O3 nanoparticles with porous carbon to form hybrid anode has been an efficient way to maintain the electronic integrity of the whole electrode since the carbon acts as a buffer layer to accommodate the volume variation and to provide multidimensional electron transport pathways during the charge/discharge process. [less ▲]

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See detailSynthesis of CO2-sourced hydrogels by using the non-isocyanate polyurethane (NIPU) chemistry
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, May 23)

Polyurethane (PUs) is one of the most important polymers and finds applications as elastomers, coatings, adhesives and sealants for automotive or construction. PU is also a material of choice in the ... [more ▼]

Polyurethane (PUs) is one of the most important polymers and finds applications as elastomers, coatings, adhesives and sealants for automotive or construction. PU is also a material of choice in the biomedical domain due to its good biocompatibility, biodegradation and mechanical properties. Especially, PUs hydrogels have been developed in the last years for biomedical applications such as soft contact lenses, wound dressing, drug delivery systems and scaffolds for tissue engineering. Traditionally, PUs are synthesized by a step-growth polymerization between diols and diisocyanates. Because of toxicity issues and a possible interdiction of isocyanates, we focused on developing new PU hydrogels using a non-isocyanate route (Figure 1). The polyurethanes formed by this route are called NIPU (for Non-Isocyanate PolyUrethane). Firstly, chemically cross-linked NIPU gels were synthesized by solvent-free polycondensation between a hydrophilic CO2-sourced polyethyleneglycol bi-cyclic carbonate and a diamine in the presence of a crosslinker. Then, NIPU gels were swelled in water till water equilibrium before characterization of their mechanical properties by compression tests. The influence of the cross-linking ratios (diamine/crosslinker ratio) and diamine structure on the swelling and the compression properties were studied. To reinforce the compression properties of NIPU hydrogel (increase in stress at break, strain at break and compression modulus), a nanofiller was dispersed in the cyclic carbonate/diamine/crosslinker formulation prior to polymerization. For the first time, nanocomposite NIPU hydrogels with high water contents (up to 80%) and good compression properties have been prepared by using low clay content. [less ▲]

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See detailOn the Habitability of Desert Varnish: a Combined Study by Micro-Raman Spectroscopy, X-Ray Diffraction and Methylated Pyrolysis-Gas Chromatography-Mass Spectrometry
Malherbe, Cédric ULg; Hutchinson, Ian; Ingley, Richard et al

in Astrobiology (2016)

In 2020, the ESA ExoMars and NASA Mars 2020 missions will be launched to Mars, searching for evidence of past and present life. In preparation for these missions, terrestrial analogue samples of rock ... [more ▼]

In 2020, the ESA ExoMars and NASA Mars 2020 missions will be launched to Mars, searching for evidence of past and present life. In preparation for these missions, terrestrial analogue samples of rock formations on Mars are studied in detail in order to optimize the scientific information that the analytical instrumentation will return. Desert varnishes are thin mineral coatings found on rocks in arid and semi-arid environments on Earth that are recognized as analogue samples. During the formation of desert varnishes (which takes many hundreds of years) organic matter is incorporated and microorganisms may also play an active role in the formation process. During this study, four complementary analytical techniques proposed for Mars missions (X-rays diffraction, Raman spectroscopy, elemental analysis and pyrolysis-gas chromatography-mass spectrometry) were used to interrogate samples of desert varnish and to describe their capacity to sustain life under extreme scenario. For the first time, both the geochemistry and the organic compounds associated with desert varnish are described using an identical set of samples. XRD and Raman spectroscopy measurements were used to non-destructively interrogate the mineralogy of the samples. In addition, the use of Raman spectroscopy instruments enabled the detection of β-carotene, a highly Raman active biomarker. The content and the nature of the organic material in the samples was further investigated using elemental analysis and methylated Py-GC-MS and a bacterial origin was determined to be likely. In the context of planetary exploration, we describe the habitable nature of desert varnish based on the bio-geochemical composition of the samples. Possible interference of the geological substrate on the detectability of pyrolysis products is also suggested. [less ▲]

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See detailInvestigation of sol-gel yttrium doped ZnO thin films: structural and optical properties
Ivanova, T; Harizanova, A; Koutzarova, T et al

in Journal of Physics: Conference Series (2016)

Nanostructured metal oxide films are extensively studied due to their numerous applications such as optoelectronic devices, sensors. In this work, we report the Y–Zn–O nanostructured films prepared by sol ... [more ▼]

Nanostructured metal oxide films are extensively studied due to their numerous applications such as optoelectronic devices, sensors. In this work, we report the Y–Zn–O nanostructured films prepared by sol-gel technology from sols with different concentration of yttrium precursor, followed by post-annealing treatment. The Y doped ZnO thin films have been deposited on Si and quartz substrates by spin coating method, then treated at températures ranging from 300-800°C. XRD analysis reveals modification of the film structure and phases in the doped ZnO films. [less ▲]

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See detailOptical characterization of Sol-Gel ZnO:Al thin films
Ivanova, T; Harizanova, A; Koutzarova, T et al

in Journal of Physics: Conference Series (2016), 700

This paper presents a sol-gel technological process for preparing thin films of ZnO and ZnO:Al. The effect of annealing treatments (500, 600, 700 and 800 oC) on their properties was studied. The ... [more ▼]

This paper presents a sol-gel technological process for preparing thin films of ZnO and ZnO:Al. The effect of annealing treatments (500, 600, 700 and 800 oC) on their properties was studied. The structural evolution with the temperature was investigated by using X-Ray diffraction (XRD). Fourier Transform Infrared (FTIR) and UV-VIS spectrophotometry were applied to characterizing the films’ vibrational and optical properties. The ZnO and ZnO:Al films possessed a polycrystalline structure. The films studied are highly transparent in the visible spectral range. The optical band gap values and the haze parameter were also determined. [less ▲]

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See detailNa2FePO4F/multi-walled carbon nanotubes for lithium-ion batteries: Operando Mössbauer study of spray-dried composites
Brisbois, Magali; Caes, Sébastien ULg; Sougrati, M.T. et al

in Solar Energy Materials & Solar Cells (2016), 148

In order to favor electronic conductivity in sodium iron fluorophosphate electrodes for lithium- or sodium-ion batteries, composites of Na2FePO4F with multi-walled carbon nanotubes (CNTs) were prepared by ... [more ▼]

In order to favor electronic conductivity in sodium iron fluorophosphate electrodes for lithium- or sodium-ion batteries, composites of Na2FePO4F with multi-walled carbon nanotubes (CNTs) were prepared by pilot-scale spray drying. Addition of multi-walled CNTs in the solution results in an excellent dispersion of the CNTs within the volume of Na2FePO4F and not only at the surface of the particles. Following a heat treatment at 600°C in argon in order to reach crystallization, X-ray diffraction and ex situ Mössbauer spectroscopy revealed the presence of significant amounts of Fe(III) and maghemite (γ-Fe2O3) in the powder. However, Na2FePO4F/CNTs composites exhibit good electrochemical performance when cycling against lithium, with a discharge capacity of 104mAhg-1 at C/10 rate and 90mAhg-1 at 1C rate. Therefore, operando 57Fe transmission Mössbauer spectroscopy analyses were carried out in order to investigate the evolution of the iron oxidation state during cycling. During the first discharge, all the Fe(III) is reduced to Fe(II), explaining the good electrochemical performance. [less ▲]

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See detailLi4Ti5O12 powders by spray-drying: influence of the solution concentration and particle size on the electrochemical properties
Jamin, Claire; Brisbois, Magali; Caes, Sébastien ULg et al

Conference (2015, June 23)

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See detailMagnetic shielding performances of YBa2Cu3O7−δ -coated silver tubes obtained by electrophoretic deposition
Devendra Kumar, N; Closset, Raphaël ULg; Wera, Laurent ULg et al

in Superconductor Science and Technology (2015), 28

We report a complete procedure to achieve multilayer YBCO thick films by electrophoretic deposition on silver tubes using a suspension of YBCO powder in butanol. With the aim to optimize the magnetic ... [more ▼]

We report a complete procedure to achieve multilayer YBCO thick films by electrophoretic deposition on silver tubes using a suspension of YBCO powder in butanol. With the aim to optimize the magnetic shielding performances of the coatings, we have carried out an extensive investigation of the influence of the deposition parameters, the multilayer deposition sequence and the intermediate/final heat treatments on the coating microstructure. Using the optimized conditions, a 24-layer YBCO coating has been successfully prepared on an 80 mm long Ag tube: the melt growth processed multilayered YBCO thick film thus obtained can shield an applied magnetic field of 1.9 mT at 77 K, the highest value per thickness unit reported so far in the literature for these materials. [less ▲]

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