On-chip micro-supercapacitors for operation in a wide temperature range

Onion-like carbon (OLC) based micro-supercapacitor electrodes prepared by electrophoretic deposition (EPD) were combined with a eutectic mixture of ionic liquids (IL), producing a micro-supercapacitor which is able to function from −50 °C to 80 °C. This device was electrochemically characterized by cyclic voltammetry and electrochemical impedance spectroscopy at different scan rates and different temperatures. At 20 °C, a capacitance of 1.1 mF.cm−2 per footprint area of device at 200 mV.s−1 within 3.7 V was measured, hence a specific energy of 15 mJ.cm−2 and a specific power of 240 mW.cm−2. At−50 °C, 76% of the capacitance wasmaintained at 10 mV.s−1 within 3.7 V. By integrating with IL, this micro-supercapacitor can be potentially used in portable electronic devices that are required to work under temperature extremes

Precipitation in original Duralumin A-U4G versus modern 2017A alloy

Precipitation in Duralumin, a historic quaternary alloy of the type: Al–Cu–Mg–Si, was never fully studied nor observed by current electron microscopy techniques. This article presents the full characterization and comparison of two alloys: a Duralumin (A-U4G) from the 1950s collected on a vintage aircraft and its modern equivalent: a 2017A alloy. The as-received and peak-aging states were analysed with DSC, SAXS and TEM advanced techniques. It is shown that old Duralumin and modern 2017A present a similar nanoprecipitation in the as-received state and behave similarly upon artificial aging. As opposed to what has been reported in the past, three types of precipitates participating in hardening were found upon aging: θ’-Al2Cu, Q’(Q)-AlCuMgSi and Ω-Al2Cu

Ultrahigh-power micrometre-sized supercapacitors based on onion-like carbon

Electrochemical capacitors, also called supercapacitors, store energy in two closely spaced layers with opposing charges, and are used to power hybrid electric vehicles, portable electronic equipment and other devices¹. By offering fast charging and discharging rates, and the ability to sustain millions of ²⁻⁵, electrochemical capacitors bridge the gap between batteries, which offer high energy densities but are slow, and conventional electrolytic capacitors, which are fast but have low energy densities. Here, we demonstrate microsupercapacitors with powers per volume that are comparable to electrolytic capacitors, capacitances that are four orders of magnitude higher, and energies per volume that are an order of magnitude higher. We also measured discharge rates of up to 200 V s⁻¹, which is three orders of magnitude higher than conventional supercapacitors. The microsupercapacitors are produced by the electrophoretic deposition of a several micrometre-thick layer of nanostructured carbon onions⁶‚⁷ with diameters of 6-7 nm. Integration of these nanoparticles in a microdevice with a high surface-to-volume ratio, without the use of organic binders and polymer separators, improves performance because of the ease with which ions can access the active material. Increasing the energy density and discharge rates of supercapacitors will enable them to compete with batteries and conventional electrolytic capacitors in a number of applications

Community-Level Responses to Iron Availability in Open Ocean Plankton Ecosystems

Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio-oceanographic and bio-omics data sets from Tara Oceans in the context of the iron products from two state-of-the-art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large-scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment

Selected wrecks and report on their condition state - Deliverable D2.1

This deliverable is written to report on the work carried out in Task 2.1 of WP2 (Wrecks), which concerns the identification and selection of WWII aircraft wrecks (corpus), their constituent materials and their main conservation problems

Etude des premiers alliages légers pour l'aéronautique: une approche interdisciplinaire aux intérêts multiples

National audienc

Open access library of aeronautical Al alloys - Deliverable D2.3

The deliverable reports on the recording of valuable information, i.e. data collected during the PROCRAFT project, in relation with the task 2.4 of WP2: «Library of reference of Al alloys used in WWII aeronautics») and the deposit of the data into an open-access online repository

Report on the characterisation of collected materials on historical aircraft - Deliverable D2.2

The present deliverable reports on the study of reference wrecks and their constituent materials carried out in Tasks 2.1 and 2.2 of WP2. It aims at characterizing materials collected on selected aircraft/wrecks including the study of the metallic Al alloys, their original protective coatings and their alteration (mainly corrosion)

Composants passifs intégrés dédiés à la conversion et au stockage de l'énergie

The work deals with the integration of passive components for the conversion and storage of energy in the general context of portable electronic devices. The development of micro-electronics lead to the miniaturization of electronic circuits, pushing the expansion of portable electronic devices usage (smart phones, tablets, digital cameras pictures ... etc) and the emergence of networks of communicating sensors for ambient intelligence. One of the challenges of the coming years is to meet the ever-increasing number of functionalities and provide energy autonomy for these different objects. Miniaturization and 3D heterogeneous integration approach are solutions to overcome the technological barriers and address these issues. In power circuits providing conversion and energy management, the size of converters is defined by the size of passive elements. I will present the work carried out since 2005 at LAAS-CNRS for the integration of passive components (coils, capacitors) on silicon dedicated to energy management circuits. The work focuses on the design, development of topologies and technologies for micro-coils (L) and integrated capacitors (C). For highdensity capacitors (above 500 nF.mm-2), silicon etching technologies were explored associated with the synthesis of high-k materials. Regarding micro-coils, to reach specifications defined by low power converters, developments mainly concern the integration of magnetic core and technologies for depositing thick insulation and metal layers. In the long term, to produce power supply on-chip, stacking of multi-functional chips are desired. We will show some ways of integration: passive chip, or passive-active co-integration. In a second part, we will discuss the energy autonomy of microsystems (sensors or other). Many research has emerged since the early 2000s around microsystems harvesting ambient energy: solar, thermal, mechanical, acoustic. Since the harvested energy is intermittent, there is the need for a buffer energy storage. In this case, the best solution is to use a supercapacitor storage element which has almost unlimited lifetime. I will present the research activities related to the integration of micro-supercapacitors on silicon. The first devices based on activated carbon and other nanostructured carbons showed very interesting performance: 250 mJ.cm-2 in energy and 200 mW.cm-2 in power respectively. Finally, research perspectives will be proposed and discussed.Les travaux présentés traitent de l'intégration des composants passifs pour la conversion et le stockage de l'énergie dans un contexte général de l'électronique nomade. Le développement de la micro-électronique conduisant à la miniaturisation des circuits électroniques a permis le boom de l'électronique nomade (smart phones, tablettes, appareils photos numériques, etc.) et l'émergence des réseaux de capteurs communicants (intelligence ambiante). Les enjeux des années à venir sont : toujours plus de fonctionnalités et l'augmentation de l'autonomie énergétique de ces différents objets. La miniaturisation et l'approche de l'intégration hétérogène 3D font partie des solutions pour lever les verrous technologiques associés à ces défis. Concernant les circuits de puissance assurant la conversion et la gestion de l'énergie, la taille des convertisseurs est définie par l'encombrement des éléments passifs les constituant. Je présenterai les travaux réalisés depuis 2005 au LAAS-CNRS permettant l'intégration sur silicium de composants passifs (bobines, condensateurs) pour ces systèmes de gestion de l'énergie. Les travaux sont axés sur la conception, le développement des topologies et des filières technologiques pour micro-bobines (L) et condensateurs intégrés (C). Ainsi, pour des condensateurs à forte densité (au-delà des 500 nF.mm-2), les technologies de gravure du silicium ont été explorées associées à la synthèse et la caractérisation de matériaux à forte permittivité diélectrique. En ce qui concerne les micro-bobines, pour répondre au cahier des charges des convertisseurs fonctionnant autour du watt, les développements se concentrent sur l'intégration du noyau magnétique ainsi que les technologies de dépôts épais d'isolants et de métaux. A long terme, pour produire des alimentations toutes intégrées sur puce, l'intégration et l'empilement de puces multi-fonctionnelles sont à concevoir. Nous montrerons quelques pistes d'intégration : puce passive (contenant bobine et condensateur sur le même substrat), ou co-intégration passif-actifs au sein de la filière d'intégration fonctionnelle. Dans un deuxième volet, nous aborderons la thématique de l'autonomie énergétique des microsystèmes (capteurs ou autre). De nombreux travaux de recherche ont émergé depuis le début des années 2000 sur les microsystèmes de récupération de l'énergie ambiante : solaire, thermique, mécanique, acoustique. Etant donné la nécessité d'un stockage tampon de l'énergie récupérée, la solution la plus pertinente est d'utiliser un supercondensateur, élément de stockage présentant des durées de vie quasi-illimitées. Je présenterai les activités de recherche liées à l'intégration de micro-supercondensateurs sur silicium. Les premiers dispositifs à base de charbon actif et autres carbones nanostructurés ont montré des performances intéressantes : près de 250 mJ.cm-2 d'énergie et 200 mW.cm-2 de puissance. Finalement, les perspectives de recherche sur ces thématiques seront proposées et discutées

High-Density 3-D Capacitors for Power Systems On-Chip: Evaluation of a Technology Based on Silicon Submicrometer Pore Arrays Formed by Electrochemical Etching

International audienceThis paper presents the state of the art technologies currently used to produce high density integrated capacitors for power systems on-chip applications. The use of high-k dielectrics and 3D patterning of silicon for reaching high specific capacitance is reviewed. Integrating capacitors monolithically on the active chip or in package of power systems is discussed and solutions are proposed for minimising series resistance and achieving a high level of integration. A technology based on nanolithography and silicon electrochemical etching is then detailed. It is shown that capacitance densities of up to 700 nF/mm² can be obtained with a submicrometer pores array in a relatively limited thickness. The advantages and disadvantages of further decreasing the pore size to nanosize pores (below 100 nm) are discussed