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Versatile, fast, and accurate frequency excursions with a semiconductor laser
No full textInternational audienceAchieving accurate arbitrary frequency excursions with a laser can be quite a technical challenge, especially when steep slopes (GHz/µs) are required, due to both deterministic and stochastic frequency fluctuations. In this work we present a multistage correction combining four techniques: pre-distorsion of the laser modulation, iterative correction, opto-electronic feedback loop, and feed-forward correction. This combination allows us not only to compensate for the non-instantaneous response of the laser to an input modulation but also to correct in real time the stochastic frequency fluctuations. We implement this multistage architecture on a commercial DBR laser and verify its efficiency, first, with monochromatic operation, and second, with highly demanding frequency excursions. We demonstrate that our multistage correction not only enables a strong reduction of the laser linewidth but also allows steep frequency excursions with a relative RMS frequency error well below 1% and a laser spectral purity consistently better than 100 kHz, even in the midst of gigahertz-scale frequency excursions
Carbon-Binder-Domain porosity extraction through lithium-ion battery electrode impedance data
No full textInternational audienceIn the field of 3-D resolved computational modelling of Lithium-ion battery electrodes, the arrangement and properties of the Carbon-Binder-Domain (CBD) play a critical role in the ion and electron transport properties through their impact on the electrode tortuosity factor. However, until now, the CBD porosity value -its main descriptor in terms of transport properties and occupied volume- has been determined through educated guesses due to the lack of an experimental approach. Here, a novel methodology is reported for the determination of the CBD internal porosity through the combination of computational modelling and experimental electrochemical impedance spectroscopy (EIS). The methodology is based on the creation of a calibration curve that relates tortuosity factor with CBD porosity through digital stochastic generation of electrode microstructures and diffusivity characterization. The curve is then compared to the EIS experimental results and analyzed through a transmission line model, yielding a good estimation of the parameters. In this work, the usefulness and the identified limitation of this approach are demonstrated using three different formulations of LiNi0.3Mn0.3Co0.3O2 (NMC 111) cathodes. To the best of the authors’ knowledge, this is the first reported method for estimating CBD porosity
Highlights from the Third National Edition of the French Industrial Chemistry Symposium (FICS 2024), Paris, France, April 2024
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High-performance poly(thioctic acid)-based thermosets featuring upcycling ability for in situ foaming enabled by dual-dynamic networks
No full textInternational audiencePolymers constructed from natural thioctic acid (TA) provide a solution for the development of sustainable materials. However, their inherent weak networks make them difficult to use in engineering materials featuring high durability and mechanical robustness. In this work, the autocatalytic dual-dynamic covalent adaptable networks (CANs) are devised by curing diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate (DGEDC) with TA and bis(paminocyclohexyl)methane (PACM). The resulting DGEDC/TA/PACM thermosets exhibit good mechanical and thermal properties (Tg of 145°C, Td5% of 289°C, tensile strength of 70 MPa, Young's modulus of 2.25 GPa), higher than previous poly(thioctic acid)-based materials.Due to topological network rearrangements induced by the exchange of disulfide bonds and tertiary amine-catalyzed transesterification reactions, they can be easily reshaped and repaired. Furthermore, they can be degraded mildly and upcycled into polyurethane foams by in-situ foaming. This strategy of autocatalytic dual-dynamic CANs will inspire the development of practical applications of poly(thioctic acid).</div
Systèmes de piles à combustible - Applications stationnaires et mobilités terrestres
No full textInternational audience<div style="">Les piles à combustible trouvent aujourd’hui desapplications dans un grand nombre de domaines. Pour cela, l’objetunitaire "pile à combustible" doit tout d’abord être intégré dansun système, lequel permet d’alimenter la pile à combustible encarburant et comburant, de mettre en forme l’énergie électriqueproduite, de gérer la chaleur au sein et autour de la pile àcombustible et de s’assurer des conditions opératoires del’ensemble via un dispositif de contrôle/commande.<br /></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;"><br /></span></font></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;">Cet article présentera tout d’abord lesprincipales caractéristiques d’un tel système de pile àcombustible, avant de se focaliser sur les applications des piles àcombustible dans le domaine de la production stationnaire d’énergieet dans celui des mobilités terrestres (véhicules personnels, bus,camions, trains).</span></font></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;"><br /></span></font></div><div style=""><br /></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;">Fuel cells today find applications in a largenumber of fields. For this, the fuel cell object must first beintegrated into a system, which makes it possible to supply thefuel cell with fuel and oxidizer, to shape the electrical energyproduced, to manage the heat at the within and around the fuel celland to ensure the operating conditions of the system via acontrol/command device.</span></font></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;"><br /></span></font></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;">This article will first present the maincharacteristics of such a fuel cell system, before focusing on theapplications of fuel cells in the field of stationary energyproduction and in that of ground mobility (personal vehicles,buses, trucks, trains).</span></font></div><div style="color: rgb(0, 0, 0); font-family: arial, helvetica; font-size: 13px;"><br /></div&g
Experimental and Computational Analysis of Slurry-Based Manufacturing of Solid-State Battery Composite Cathode
No full textThe rheological properties of the electrode slurry significantly influence the manufacturing process of solid-state batteries (SSBs), affecting coating quality and the resulting cathode microstructure. The correlation between slurry attributes and final electrode characteristics is analyzed using particle size and solid content as key metrics. The performed coarse-grained molecular dynamics simulations closely fit experimental viscosity, indicating the model's suitability for predicting slurry behavior. Then the microstructural properties of the dry and calendered electrodes are calibrated with the experiments. The simulation workflow is fitted completely using only two sets of force fields, one for the slurry and the other for the dry state of the electrode. The effective electronic conductivities are contingent on the particle size, without showing significant limitation on cathode rate capabilities. This comprehensive study highlights the intricate interplay between slurry solid content, microstructure design, and manufacturing processes in optimizing SSB performance. Consistent slurry characteristics are crucial for uniform electrode coating while optimizing particle size and solid content improves electrode porosity. The findings provide valuable insights for enhancing SSB design and manufacturing processes for the adaptation of already established scaling up technologies
Non-invasive analyze of boron and lithium in 18th century Chinese porcelain enamel and glaze: A PIXE/PIGE study
No full textInternational audienceIn enamelling technology, the natural (raw) materials used before the middle of the 19th century combine by nature different elements whose role in the process can be important even in small quantities. Some of these elements – particularly boron, lithium – are difficult to measure non-invasively and are therefore rarely analyzed. Boron and lithium, often used as additional flux in glazes, were quantified by PIXE and PIGE analysis with the extracted beam of the New AGLAE facility in 18th century porcelains samples, French soft-paste from the Manufacture royale de Sèvres and Chinese hard-paste from the reign of the Qing dynasty. The results were compared to previous conclusions made using SEM/EDS and pXRF in order to assert the presence of boron, previously suspected by Raman microspectroscopy, and to detect the presence of lithium, both provided by a particular flux (borax), mentioned in the historical French and Chinese enamel recipes
Elucidating the Interplay of Specific Surface, Porosity, and Permeability and Their Ultimate Role on Electrochemical Behavior of Compacted Li-Powder Electrodes
No full textInternational audienceLi-powder anodes have been proposed as an alternative to Li-foil electrodes, as their high-surface area is expected to reduce the local current density and consequently hinder dendrite formation, which is at the origin of several drawbacks in Li metal batteries. In this work, a comprehensive theoretical/experimental approach is proposed to elucidate how the interplay of several parameters such as effective surface, porosity, and permeability of cold-pressed Li-powder electrodes evolve with the compaction pressure and how these features ultimately affect the electrochemical performance of a porous electrode. The theoretical calculations indicate that maintaining high porosity is crucial, and there is also the need to maintain particle size within an optimal range. This balance is essential to achieving a compromise between maximizing effective surface area and ensuring adequate permeability of the porous electrode. Experimentally, only Li-powder electrodes compacted at low pressure (1 MPa) are permeable enough to allow the penetration of the electrolyte into the porosity of the electrode. Interestingly, the Li-powder electrode compacted at 1 MPa is also the only porous electrode to perform better than Li-foil electrodes in electrochemical tests. Post mortem analyses after cycling reveal that the morphology of lithium electrodeposition on this specific electrode is significantly distinct from the other ones. The main findings highlight that even though Li powder can present a specific surface area a hundred times higher than that of a Li foil, this surface must be electrochemically available to result in outstanding electrochemical properties. Therefore, the particle size and the compaction pressure applied to shaping Li-powder electrodes with an optimized morphology are critical parameters to be considered for their preparation
β-Cyclodextrin-NHC-Au(I)-Catalyzed Enantioconvergent 1,5-enyne Cycloisomerizations
No full textInternational audienceEnantioconvergent transformations from racemic mixtures are attractive since they allow to generate optically active products with full conversion despite the possibly adverse kinetic resolution process. When dealing with gold(I)-catalyzed cycloisomerizations, chirality transfer from the precursor is another possible diverting pathway, which renders enantioconvergence challenging. Not surprisingly, enantioconvergent Au(I)-catalyzed processes have re- mained extremely rare. Herein, we show that cavity-driven catalysis using β-Cyclodextrin-NHC-Au(I) complexes bring opportunities to conduct highly enantioconvergent cycloisomerizations of 1,5-enynes, -enynols and –enynyl esters
Applications of Biodegradable Polymers in the Encapsulation of Anticancer Metal Complexes
No full textInternational audienceAbstract Metal complexes have recently attracted a lot of attention, particularly as anticancer and antibacterial agents, owing to their versatile mechanisms and easily tunable characteristics. However, the application of such compounds in a medical context, especially in cancer treatment, has been hampered due to their limited solubility and stability in water and aqueous solutions, as well as a lack of selectivity. To address these limitations, several approaches have been developed to improve the targeted delivery of these compounds and their solubility. The first strategy involves the physical encapsulation of these metal complexes within carriers to facilitate controlled drug release. The second strategy involves covalently linking metal complexes to polymers, creating prodrugs that can be converted to active drugs at a more controllable rate. Despite the increasing variety of polymers available, the need to develop those able to be metabolized by the body, producing non‐toxic residues, remains crucial for effective treatment, particularly in the area of diseases such as cancer. In this perspective article, an overview of recent developments in the encapsulation of metal complexes using biodegradable polymers for cancer therapy is provided. It is specifically highlighting how the formed nanoparticles (NPs) enhance the selectivity and toxicity toward cancer cells compared to the parent metal complex, while simultaneously reducing the harmful side effects of traditional chemotherapies, opening the door for using them in combination therapies (PDT, PTT)