L’intégration des énergies renouvelables pour la production d’électricité impose une bonne maîtrise des flux énergétiques et le développement de nouveaux dispositifs de stockage de l’électricité est devenu un élément clé pour corriger l’intermittence des énergies éolienne et photovoltaïque. Parmi les dispositifs de stockage électrochimiques existants, les batteries se caractérisent par une grande densité d’énergie, mais souffrent d’une faible puissance, tandis que les supercondensateurs électrochimiques ont une faible densité d’énergie, mais conservent l’avantage d’une grande puissance. La difficulté à réunir ensemble puissance et énergie laisse vacant un large domaine du diagramme de Ragone, devenu la cible de nouveaux dispositifs hybrides. Une stratégie récente pour améliorer les performances des dispositifs de stockage consiste à greffer des molécules électroactives sur les matériaux d’électrodes, afin d’ajouter une contribution faradique au stockage. Cette approche modulaire permet de construire un matériau hybride sur mesure en fonction de l’application visée, mais la stratégie du greffage montre des limitations et des efforts restent à faire pour concilier les bonnes propriétés des molécules et du carbone, souvent utilisé pour cette application. Au cours de cette thèse, l’impact des propriétés de texture de matériaux carbonés poreux sur la modification chimique d’électrodes de supercondensateurs a été étudié afin de rationaliser la sélection des carbones et améliorer l’intégration des molécules. Dans cette perspective, le greffage du liant, jusqu’à présent considéré comme une masse "morte", sera considéré comme une alternative au greffage du carbone. / The integration of renewable energy into the production of electricity, forces us to conceive innovative charge storage systems to deal with the issue of the intermittent supply of wind and solar-generated electricity. At present, electric storage devices range from electrochemical capacitors, which can supply high power densities but suffer from low energy densities, to batteries, which are considered as a high-energydensity and low-power-density technology. The difficulty of combining the high power density of supercapacitors with the high energy density of batteries creates a large free area in the Ragone diagram that is targeted by new hybrid energy systems. A recent strategy consists in grafting fast redox-active small molecules onto the surface of porous carbons for producing organic storage devices at the frontier between electrochemical capacitors and batteries. This modular approach allows designing universal electrode materials applicable both for anode and cathode, but efforts are still needed for improving the integration of molecules in the microporous structure of carbons. In this thesis, we have studied the impact of textural properties of a series of carbons on the electrochemical performances of the corresponding carbon-molecules composite materials to rationalize the selection of carbons and enhancing the integration of molecules in the microposity of carbons. An novel approach, presented at the end of this work, for improving performance without decreasing the double-layer capacitance contribution and hindering the ionic transportation is to use the binder for the charge storage by grafting molecules onto its polymeric skeleton.

Nowadays, new approaches to fabricate high-performance electrode materials are of vital importance in the renewable energy field. Here, we present a facile synthesis procedure of 3D Ni(OH)2/graphene hybrids for supercapacitors via synchronous electrochemical-assisted exfoliation and assembly of graphene on 3D Ni(OH)2 networks. With the assistance of an electric field, the electrochemically exfoliated high-quality graphene can be readily, uniformly assembled on the surfaces of 3D Ni(OH)2. When serving as electrode materials for supercapacitors, the resulting 3D Ni(OH)2/graphene composites exhibited excellent specific capacitance (263 mF cm−2 at 2 mA cm−2), remarkable rate capability and super-long cycle life (retention of 94.1% even after 10 000 continuous charge–discharge cycles), which may be attributed to their highly porous, stable 3D architecture as well as uniform, firm anchoring of ultrathin graphene on their surfaces. Therefore, our approach provides a facile strategy for the large-scale synthesis of high-quality graphene based composites towards various applications.

Nitrogen-doped (N-doped) porous carbons have drawn increasing attention due to their high activity for electrochemical catalysis, and high capacity for lithium-ion (Li-ion) batteries and supercapacitors. So far, the controlled synthesis of N-enriched ordered mesoporous carbons (N-OMCs) for Li-ion batteries is rarely reported due to the lack of a reliable nitrogen-doping protocol that maintains the ordered mesoporous structure. In order to realize this, in this work, ordered mesoporous carbons with controllable N contents were successfully prepared by using melamine, F127 and phenolic resin as the N-source, template and carbon-source respectively via a solvent-free ball-milling method. The as-prepared N-OMCs which showed a high N content up to 31.7 wt% were used as anodes for Li-ion batteries. Remarkably, the N-OMCs with an N content of 24.4 wt% exhibit the highest reversible capacity (506 mA h g−1) even after 300 cycles at 300 mA g−1 and a capacity retention of 103.3%. N-OMCs were also used as electrode materials in supercapacitors and a capacity of 150 F g−1 at 0.2 A g−1 with stable cycling up to 2500 times at 1 A g−1 was achieved. These attractive results encourage the design and synthesis of high heteroatom content ordered porous carbons for applications in the field of energy storage and conversion.

Ce travail porte sur l’élaboration et la caractérisation d’électrolytes destinés à l’application supercondensateurs sur des gammes de températures étendues. Dans un premier temps, trois électrolytes à base de liquides ioniques (LI) et d’un solvant organique, la-butyrolactone (GBL) ont été sélectionnés. Leurs stabilités électrochimiques et thermiques, ainsi que leurs propriétés physico-chimiques telles que la conductivité ionique et la viscosité, ont été mesurées entre -50°C et 100°C. Ces expériences ont également été effectuées sur les LI purs (EMITFSI, Pyr13FSI et Pyr14TFSI), ce qui a permi de mettre en avant l’intérêt de l’ajout de solvant sur les LI, en particulier pour des applications à basses températures. Des études de vieillissements à 100°C et -50°C de supercondensateurs classiques (séparateur en cellulose) ont permi de démarquer l’électrolyte EMITFSI/GBL de par sa grande stabilité à ces températures extrêmes.Dans un second temps, des gels électrolytiques ont été synthétisés afin d’être utilisés comme séparateurs, évitant ainsi d’éventuelles fuites d’électrolyte. Il s’agit de Réseaux semi-Interpénétrés de Polymères (semi-RIP), dont le réseau principal est formé à partir de poly(oxide d’ethylène) (POE), dans lequel se trouvent des chaines de caoutchouc naturel: le nitrile butadienerubber (NBR). Le réseau POE assure une bonne conductivité ionique, tandis que l’élastomère (NBR) améliore la tenue mécanique du gel. Différentes proportions d’électrolytes ont été testées lors de la synthèse de gels, ainsi que différents ratios NBR/POE. De la même façon que pour les électrolytes liquides, les gels électrolytiques ont été caractérisés. A 100°C, les performances des supercondensateurs constitués du séparateur gel le plus intéressant (NBR/PEO : 40/60 en masse) sont similaires, voire meilleures que celles des supercondensateurs classiques. Lors de travaux futurs, ces gels électrolytiques seront également testés à basse température. / This work has been focusing on the synthesis and characterization of electrolytes for supercapacitor applications over a wide temperature range. First, three electrolytes based on Ionic Liquids (ILs) and an organic solvent, -butyrolactone (GBL) were selected. Many characterizations of these IL/GBL mixtures were performed from -50°C to 100°C: electrochemical and thermal stabilities, but also ionic conductivity and viscosity. These experiments were also performed on the three neat ILs (EMITFSI, Pyr13FSI and Pyr14TFSI). Results were compared to IL/GBL mixtures and brought to light the benefit from solvent addition upon ILs for applications at low temperature. Fast ageing has been realized at 100°C and -50°C on classical coin cells (cellulose separator), and systems based on the EMITFSI/GBL electrolyte have the longest lifetime.In a second time, gel electrolytes have been synthesized in order to be used as separators, thus preventing electrolyte leakage in the supercapacitor. It was decided to study semi-InterPenetrating Networks (semi-IPNs) synthesized with EMITFSI/GBL as the electrolyte. Semi-IPNs are based on Poly(ethylene oxide) (PEO) and Nitrile Butadiene Rubber (NBR). The PEO network facilitates the ion mobility of the electrolyte while NBR chains improve the mechanic behavior of the gel. Different proportions of electrolytes were tested, as well as different ratios NBR/PEO. Gel electrolytes have been characterized similarly to liquid electrolytes (ionic conductivity, electrochemical and thermal stability). At 100°C, performances of supercapacitors composed of the most interesting gel electrolyte ((NBR/PEO : 40/60 by weight) are at least as good as those of classical separators. Future work will be devoted to ageing at low temperature.

Cette thèse a consisté en la fabrication d’électrodes de charbon actif frittées par SPS destinées aux supercondensateurs à double couche électrochimique. L’influence des paramètres de frittage (température, pression, durée du palier isotherme et vitesses de chauffe et de refroidissement) sur les propriétés structurales et microstructurales des pastilles de charbon actif a été évaluée par diffraction des rayons X, microscopie électronique à balayage et en transmission, spectrométrie de photoélectrons X, mesures de surface spécifique et de volume microporeux et détermination des propriétés mécaniques. Les performances électrochimiques des pastilles de charbon actif frittées sélectionnées pour leurs bonnes propriétés de volume microporeux, de résistance mécanique à l’électrolyte et de masse volumique élevée ont été déterminées par mesures galvanostatiques et de spectrométrie d’impédance. Un gain en capacité volumique de 31% a été obtenu pour un supercondensateur composé d’électrodes de charbon actif pur de 200 μm d’épaisseur frittées à 1100°C – 50 MPa par rapport à un supercondensateur composé d’électrodes de production de Blue Solutions. Cependant sa résistance série est deux fois supérieure à celle d’un supercondensateur de production de volume identique. Des résultats prometteurs de frittage multi-pastilles, possédant des propriétés microstructurales proches, indiquent une voie possible d’industrialisation du procédé SPS pour la fabrication d’électrodes frittées de charbon actif destinées aux supercondensateurs. / This thesis has consisted in the manufacturing of activated carbon electrodes sintered by SPS for Electric Double-Layer Capacitors (EDLCs). The influence of sintering parameters (temperature, pressure, isothermal dwell duration, heating and cooling rates) on structural and microstructural properties of sintered activated carbon pellets has been evaluated by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectrometry, specific area and microporous volume measurements and determination of mechanical properties. The electrochemical performances of sintered activated carbon pellets selected for their good properties in terms of microporous volume, mechanical resistance in the electrolyte and high density were determined by galvanostatic and impedance spectrometry measurements. A 31% increase of the volumetric capacity was obtained for a supercapacitor composed of 200 μm thick electrodes of pure activated carbon sintered at 1100°C – 50 MPa, relative to a supercapacitor composed of industrial electrodes from Blue Solutions company. However, its serial resistance is twice larger than that of an industrial of identical volume. Promising results of multi-pellet sintering, possessing close microstructural properties, indicate a possible way of industrialization of SPS process for the manufacturing of sintered activated carbon electrodes for supercapacitors.

Within the different available electrochemical energy storage systems, supercapacitors stand out due to their high power densities and ultra-long cycle life. Their key-components are the electrode materials where the charge accumulation takes place and therefore many different approaches for the synthesis of carbonaceous electrode structures with well-defined pore systems are available. This review focuses on different strategies for tailoring porous carbon materials from the micropore level, over mesopores to macropores and even external or inter-particular porosity. A wide range of materials such as activated carbons, templated carbons, carbide-derived carbons, carbon nanotubes, carbon aerogels, carbon onions, graphenes and carbon nanofibers are presented, always in relation to their pore structure and potential use in supercapacitor devices.

No description available.

Projektet beskriver ett tillvägagångssätt för att alstra energi genom solceller och piezoelektronik. Ett kretskortsbaserat system designades som utnyttjade superkondensatorer som lagringsenhet. Planen var att integrera systemet i en sko. Genom denna teknik kan man då substituera eller minimera batteriladdningen för smarta enheter eller mindre anordningar. Det önskvärda resultatet med projektet var att se om det gick att koppla detta system till en mikrokontroller som kunde drivas på låg spänning. Rapporten fick ett positivt resultat med en konstant utspänning på 1.8 volt som kunde driva en mikrokontroller. Dock tog det lång tid för superkondensatorerna att laddas upp på grund av den impedans som fanns i systemet. Aktiviteter som utnyttjar detta system kommer att påverka uppladdningens resultat. Detta gör kretsen optimal för aktiviteter som involverar rörelse och sol, såsom hiking. / The past couple of decades gave rise to smartphones, smart watches, and smart homes. Now researchers are looking for ways to make smart clothing. One use case of smart clothing is smart shoes which can give some very useful sensed information especially in the sports industry and healthcare. Such sensed data include temperature, distance and calories, fall detection and many more. This application scenario can be designed to be battery free if we make use of the human motion and solar power. Many research papers exist which present how to exploit swing and shock excitations from the shoes to harvest energy. In this project this energy combined with solar energy will be used to power a low driven MCU. I design a pcb which include solar panels and piezoelectric modules to store the energy in supercapacitors. The goal is to integrate this pcb in a shoe, meaning that it has to have a small size and low power. The results of the project showed that a constant voltage at 1.8 volt could be achieved however recharge time is a factor to take into consideration. The system showed positive results for activities including movements and sun such as hiking.

Monolithic integration of iontronic devices is a key challenge for future miniaturization and system integration. The G-Cap, a novel iontronic element, is a switchable supercapacitor with gating characteristics comparable to transistors in electronic circuits, but switching relies on ionic currents and ion electroadsorption. The first monolithic in-plane G-Cap integration through 3D-inkjet printing of nanoporous carbon precursors is reported. The printed G-Cap has a three-electrode architecture integrating a symmetric “working” supercapacitor (W-Cap) and a third “gate” electrode (G-electrode) that reversibly depletes/injects electrolyte ions into the system, effectively controlling the “working” capacitance. The symmetric W-Cap operates with a proton-conducting hydrogel electrolyte PVA/H₂SO₄ and shows a high capacitance (1.6 mF cm⁻²) that can be switched “on” and “off” by applying a DC bias potential (-1.0 V) at the G-electrode. This effectively suppresses AC electroadsorption in the nanoporous carbon electrodes of the W-Cap, resulting in a high capacitance drop from an “on” to an “off” state. The new monolithic structures achieve high rate performance, reversible on-off switching with an off-value reaching 0.5 %, which even surpasses recently reported values. Establishing technologies and device architectures for functional ionic electroadsorption devices is crucial for diverse fields ranging from microelectronics and iontronics to biointerfacing and neuromodulation.

Ce travail de recherche présente la préparation et la caractérisation de matériaux monolithiques hautement poreux dérivés majoritairement de ressources naturelles. L'objectif était de préparer de nouveaux gels biosourcés jusqu'à 91%, de proposer des alternatives au séchage supercritique au CO2, et d'étudier quelques propriétés d'intérêt de tels gels après séchage, non seulement à l'état organique mais, dans certains cas, après pyrolyse pour obtenir des gels de carbone. A ces fins, le tannin et le soja ont été testés comme précurseurs, à différentes concentrations et différents pH, et trois voies de séchages ont été utilisées : supercritique, lyophilisation et séchage évaporatif. Les gels obtenus ont été caractérisés en termes de densité, porosité, distributions de tailles de pores et surfaces spécifiques, qu'ils soient sous forme organique ou carbonée selon l'application envisagée ou le type de porosité attendue. Leurs propriétés mécaniques et thermiques ont aussi été mesurées. La très large gamme de textures poreuses obtenues a permis de proposer des applications en tant qu'isolants thermiques, supports de catalyseur, ou électrodes de condensateur électrochimiques, selon les cas / This manuscript presents the preparation and the characterization of highly porous monolithic materials mainly derived from natural resources. The objectives were to: (i) develop new gels, biosourced up to the 91% level; (ii) suggest alternatives to supercritical drying in CO2, and (iii) investigate properties of interest for such gels in the organic state and, in some cases, after pyrolysis for obtaining carbon gels. For those purposes, tannin and soy flour were tested as precursors, at different concentrations and different pH, and three ways of drying were used: supercritical drying, freeze drying and evaporative drying. The obtained gels were characterized in terms of density, porosity, pore size distributions and specific surface area, whether in organic or in carbon form, depending on the intended application or expected type of porosity. Mechanical and thermal properties were also measured. The obtained broad range of porous textures allowed suggesting applications such as thermal insulators, catalyst supports or electrodes for electrochemical capacitors