Switchable hydrophobic-hydropholic fluorinated layer for offset processing

The use of heat-sensitive printing plate precursors has become very popular as one of the‘dry’ lithographic methods that have recently been proposed to comply with environmentalrequirements, A major problem associated with most ablative plates, however, is thegeneration of ablation particles that may contaminate the electronics and optics of thedevice. The objective of the present study is to provide a ‘processless’ method, through aplasma-enhanced fluorination (PEF) treatment involving a fluorinated gas [1]

Increasing tap density of carbon-coated Na3V2(PO4)2F3 via mechanical grinding: good or bad idea?

International audiencePolyanionic positive electrode materials such as Na3V2(PO4)2F3 are renowned for their exceptional rate performance and long-term stability during cycling. However, they present low tap densities that penalize the volumetric energy density when it comes to practical applications. In this study, we successfully increased the tap density of carbon-coated Na3V2(PO4)2F3 by 40% through mechanical grinding of dense particles previously obtained via the solid-state reaction, resulting in an impressively high tap density of 1.4 g/cm3. Comprehensive structural and microstructural investigations revealed that this mechanical process reduces both particle and crystallite sizes without affecting the structure or the composition of the active material. Besides extensive electrochemical experiments, including evaluation of capacity retention upon long-term cycling and at high rates, electrochemical impedance spectroscopy as well as self-discharge tests were conducted to assess the impact of the change in microstructure on the energy storage performance. Furthermore, thermal stability assessments of electrodes in contact with electrolytes and at different states of charge were also performed to complete the study and provide a complete overview of the influence of such mechanical grinding processes commonly employed in the field of energy storage

From irreversible transformation of VO2 to V2O5 electrochromic films

Since its discovery, electrochromism, known as a modulation of the optical properties under an applied voltage, has attracted strong interest from the scientific community and has proved to be of significant utility in various applications. Although vanadium dioxide (VO2) has been a candidate of extensive research for its thermochromic properties, its intrinsic electrochromism has scarcely been reported so far. In this study, multi-electrochromism is described from VO2 thick films. Indeed, VO2 opaque film, doctor bladed from homemade monoclinic VO2 powder, shows a pronounced color modulation from orange to green and blue associated with an amorphization-recrystallization phenomenon upon cycling in lithium-based electrolyte. The strong memory effect allows to follow the coloration mechanism by combining various ex-situ and in-situ characterizations addressing both structural and electronic aspects. Upon cycling the multi-chromism of VO2 finds its origin in a transformation of VO2 into orange-V2O5 on oxidation while in reduction the blue color lithiated state illustrates a mixed vanadium oxidation state

Fabrication and characterization of copper and copper alloys reinforced with graphene

The consistent rise in current density within electrical wires leads to progressively more substantial heat losses attributed to the Joule effect. Consequently, mitigating the electrical resistivity of copper wires becomes imperative. To attain this objective, the development of a composite material that incorporates a more conductive reinforcement, like graphene, holds great promise. The conception of a copper/graphene composite using a powder metallurgy-based approach is presented. An optimum graphene quantity of 0.06 vol.% was obtained by calculation in order to limit the phenomenon of overlapping layers. This synthesis technique enables the dispersion of graphene and the meticulous control of the interface through the growth of CuO(Cu) nanoparticles that are tightly bonded to the reinforcement. The increase in the hardness of the various materials with separation of the graphene sheets by ultrasonic treatment (55.3 to 67.6 HV) was obtained. It is an indicator of the correct distribution of the reinforcement. The influence on the electrical properties of dendritic copper (ρe = 2.30 µV.cm) remains limited, resulting in a modest reduction in electrical resistance of around 1.4%. Nevertheless, for flake copper (2.71 µV.cm) and brass (7.66 µV.cm), we achieved a more substantial reduction of 2.7% and 10%, respectively. With the improvement of graphene quality, there exists a greater potential for further enhancing the electrical properties

Investigation of the interaction between adsorbed water and various morphologies of boehmite nanoparticles prepared by continuous supercritical hydrothermal synthesis

Boehmite applications are often subject to specific characteristics in terms of morphologies and surface properties. The versatile continuous supercritical hydrothermal method allows synthesizing various boehmite morphologies from rhombic to hexagonal platelet-like nanoparticles depending on the preferential adsorption of part of the precursor after transformation species on the (020) surface resulting in a preferential growth along [001] and mostly [100] directions. This adsorption on surface free sites plays the role of morphology stabilizer and results in the reduction of adsorbed water. The interaction between adsorbed water and the boehmite morphology depends on various parameters: 1) the structure order of boehmite as exhibited by XPS analysis associated with 1H Solid-State NMR spectroscopy and, 2) the number of available free sites, which tend to be filled by the adsorption of nitrates as observed by Raman spectroscopy

Fluoration douce et topotactique de composés intermétalliques/ Le rôle clef de la liaison C−F

International audienc

Improved electrochemical performance for high voltage spinel LiNi0.5Mn1.5O4 modified by supercritical fluid chemical deposition

International audienceAmong candidates at the positive electrode of the next generation of Li-ion technology and even beyond post Li-ion technology as all-solid-state batteries, spinel LiNi0.5Mn1.5O4 (LNMO) is one of the favorites. Nevertheless, before its integration into commercial systems, challenges still remain to be tackled, especially the stabilization of interfaces with the electrolyte (liquid or solid) at high voltage. In this work, a simple, fast, and cheap process is used to prepare a homogeneous coating of Al2O3 type to modify the surface of the spinel LNMO: the supercritical fluid chemical deposition (SFCD) route. This process is, to the best of our knowledge, used for the first time in the battery field. Significantly improved performance was demonstrated vs those of bare LNMO, especially at high rates and for highly loaded electrodes

Improved electrochemical performance for high voltage spinel LiNi0.5Mn1.5O4 modified by supercritical fluid chemical deposition

International audienceAmong candidates at the positive electrode of the next generation of Li-ion technology and even beyond post Li-ion technology as all-solid-state batteries, spinel LiNi0.5Mn1.5O4 (LNMO) is one of the favorites. Nevertheless, before its integration into commercial systems, challenges still remain to be tackled, especially the stabilization of interfaces with the electrolyte (liquid or solid) at high voltage. In this work, a simple, fast, and cheap process is used to prepare a homogeneous coating of Al2O3 type to modify the surface of the spinel LNMO: the supercritical fluid chemical deposition (SFCD) route. This process is, to the best of our knowledge, used for the first time in the battery field. Significantly improved performance was demonstrated vs those of bare LNMO, especially at high rates and for highly loaded electrodes

Radiolabeling, Quality Control and In Vivo Imaging of Multimodal Targeted Nanomedicines

International audienceFollowing our previous study on the development of EGFR-targeted nanomedicine (NM-scFv) for the active delivery of siRNA in EGFR-positive cancers, this study focuses on the development and the quality control of a radiolabeling method to track it in in vivo conditions with nuclear imaging. Our NM-scFv is based on the electrostatic complexation of targeted nanovector (NV-scFv), siRNA and two cationic polymers. NV-scFv comprises an inorganic core, a fluorescent dye, a polymer layer and anti-EGFR ligands. To track NM-scFv in vivo with nuclear imaging, the DTPA chemistry was used to radiolabel NM-scFv with 111In. DTPA was thiolated and introduced onto NV-scFv via the maleimide chemistry. To obtain suitable radiolabeling efficiency, different DTPA/NV-scFv ratios were tested, including 0.03, 0.3 and 0.6. At the optimized ratio (where the DTPA/NV-scFv ratio was 0.3), a high radiolabeling yield was achieved (98%) and neither DTPA-derivatization nor indium-radiolabeling showed any impact on NM-scFv’s physicochemical characteristics (DH ~100 nm, PDi < 0.24). The selected NM-scFv-DTPA demonstrated good siRNA protection capacity and comparable in vitro transfection efficiency into EGFR-overexpressing cells in comparison to that of non-derivatized NM-scFv (around 67%). Eventually, it was able to track both qualitatively and quantitatively NM-scFv in in vivo environments with nuclear imaging. Both the radiolabeling and the NM-scFv showed a high in vivo stability level. Altogether, a radiolabeling method using DTPA chemistry was developed with success in this study to track our NM-scFv in in vivo conditions without any impact on its active targeting and physicochemical properties, highlighting the potential of our NM-scFv for future theranostic applications in EGFR-overexpressing cancers

Multi-scale characterization of submicronic NASICON-type solid electrolyte Li1.3Al0.3Ti1.7(PO4)3 degraded by spark plasma sintering

One of the most promising and developed disruptive technology of energy storage for the future is all solid-state batteries. The NASICON phase LATP (Li1.3Al0.3Ti1.7(PO4)3) is widely studied especially thanks to its high ionic conductivity and mechanical strength. However, high temperature densification is required to obtain a dense and conductive material. Here we explore the fast sintering by Spark Plasma Sintering (SPS) of submicronic LATP particles, and the impact of the heating rate on the physico-chemical and transport properties of the pristine powder. High-speed rate for the sintering process induces particles’ growth, avoiding any reduction of titanium. The impurity AlPO4 plays a major role on the conductivity, depending on its content but also on its distribution within the composite, either as a coating (surface modification) or as crystalline particles within the grain boundaries. An intimate understanding of the ceramic composites was achieved using combination of advanced characterization techniques to get a multi-scale description of the material, from the pristine to the sintered states, from the surface to the bulk, and from the atomic long range to the local scales. Sharing these fundamental results is essential, with among other motivations, the spreading of our interpretation of complex spectroscopic results (Electronic Spin Resonance (ESR) spectroscopy, solid-state Nuclear Magnetic Resonance (NMR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS)), key for characterization of reactivities at interfaces in this work and in others.Laboratory of excellency for electrochemical energy storag