L’intégration des supercondensateurs dans les applications de type véhicule hybride nécessite la connaissance de leur comportement au cours du vieillissement. Ainsi, l’objectif de cette thèse est l’évaluation du vieillissement et la définition d’un modèle permettant la prédiction de l’état de santé des supercondensateurs. Les résultats de vieillissement sont présentés en s’intéressant principalement à l’évolution des performances durant le vieillissement accéléré en fonction de la température, de la tension et de la durée des arrêts dans le cas du cyclage. Un modèle de vieillissement est défini pour décrire l’évolution des performances en s’attachant aux principaux mécanismes de vieillissement. / The integration of ultracapacitors in applications like hybrid requires knowledge of their behavior during aging. Thus, the objective of this thesis is the evaluation of aging and the definition of a model for predicting the health of supercapacitors. The aging results are presented focusing mainly on the evolution of performance during accelerated aging function of temperature, voltage and duration of stops in the case of cycling. An aging model is defined to describe the evolution of performance by focusing on the key mechanisms of aging.

Abstract The main objectives of this thesis are to synthesize macroscopic well-aligned multi-walled carbon nanotube films and, based on their electrical conductivity, porosity and structural uniformity, highlight potential applications for further development. In this thesis, catalytic chemical vapour deposition from ferrocene-xylene precursors is optimized to grow high quality films of long, aligned multi-walled carbon nanotubes on lithographically patterned templates in high (~800ºC) temperatures. The impacts of reaction time, temperature and precursor concentration on MWCNT film quality (film thickness, purity, density and nanotube diameter distribution) are studied. Because of the excellent control of growth selectivity and film thickness inherent to the method, several interesting applications, including solar cell and capacitor electrodes, contact brushes, coolers, particulate filters and catalyst membranes, have been developed for nanotube films in collaboration between Finnish and international research groups over the past few years. In this thesis, advanced capacitor electrodes with improved charge storage and efficient particulate filters are discussed in closer detail. As the high temperatures used for growing high quality carbon nanotubes often cause complications in cases where nanotubes need to be directly integrated with other materials, experiments were also conducted with the aim of making the growth temperature as low as possible. After testing several catalyst and precursor combinations, cobalt nanoparticles deposited on silica surfaces were found to form carbon nanotubes from vaporized cyclopentene oxide precursor already at 470°C. The results show that catalytic chemical vapour deposition is a feasible and versatile method that can be combined with photolithography to produce multi-walled carbon nanotube films with desired footprint area and thickness on various substrates. The demonstrated new applications and technical solutions are expected to contribute to further development leading to competitive practical devices based on carbon nanotubes. / Tiivistelmä Tämän väitöstyön päätavoitteina ovat makroskooppisten, yhdensuuntaisista moniseinämäisistä hiilinanoputkista koostuvien kalvojen valmistaminen ja sovellutusten esittäminen perustuen kalvojen sähkönjohtavuuteen, huokoisuuten ja rakenteelliseen yhdenmukaisuuteen. Katalyyttis-kemiallinen höyryfaasikasvatusmenetelmä on optimoitu korkealaatuisten, yhdensuuntaisista, pitkistä moniseinämäisistä hiilinanoputkista koostuvien kalvojen tuottamiseen korkeissa lämpötiloissa (~800ºC) fotolitografialla kuvioiduille kasvualustoille käyttäen ferroseeni/ksyleeni-lähtöainetta. Reaktioajan, lämpötilan ja lähtöainepitoisuuden vaikutusta nanoputkikalvon laatuun on tutkittu tarkastelemalla kalvon paksuutta, puhtautta, tiheyttä ja nanoputkien läpimittajakaumaa. Erinomaisen kasvuselektiivisyyden ja kalvon paksuuden kontrolloimisen ansiosta nanoputkikalvoja voidaan räätälöidä useisiin mielenkiintoisiin sovellutuksiin (esim. aurinkokennot ja kondensaattorin elektrodit, hiiliharjat, jäähdyttimet, partikkelisuodattimet ja katalyyttikalvot), joita olemme kehittäneet viime vuosina yhdessä suomalaisten ja kansainvälisten tutkimusryhmien kanssa. Tässä väitöstyössä on tarkasteltu lähemmin uudentyyppisiä kondensaattorielektrodeja, joilla on parantunut sähkövarauksen varastointikyky, sekä tehokkaita partikkelisuodattimia. Hiilinanoputkien kasvattaminen korkeissa lämpötiloissa aiheuttaa usein ongelmia integroitaessa nanoputkia toisiin materiaaleihin. Tästä johtuen tutkimuksessa pyrittiin saamaan nanoputkien kasvatuslämpötila mahdollisimman alhaiseksi testaamalla useita lähtöaine-katalyytti-kombinaatioita, joista koboltti-nanopartikkelit piidioksidin päällä ja syklopenteenioksidi lähtöaineena muodostivat hiilinanoputkia jo 470°C:ssa. Tulosten perusteella katalyyttis-kemiallinen höyryfaasikasvatusmenetelmä yhdistettynä fotolitografiaan on hyvin monipuolinen tapa tuottaa moniseinämäisiä hiilinanoputkia halutulla kuviolla ja kalvonpaksuudella erilaisille substraateille. Tässä väitöstyössä demonstroitujen uusien sovellutusten ja teknisten ratkaisujen odotetaan johtavan uusiin, hiilinanoputkiin perustuviin kilpailukykyisiin käytännön laitteisiin.

Philosophiae Doctor - PhD

With the discovery of conductivity in doped polyacetylene (PA), a new era in synthetic metals has emerged by breaking the traditionally accepted view that polymers were always insulating. Conducting polymers are essentially characterized by the presence of conjugated bonding on the polymeric back bone, which facilitates the formation of polarons and bipolarons as charge carriers. Among the numerous conducting polymers synthesized to date, polypyrrole (PPy) is by far the most extensively studied because of prodigious number of applications owing to its facile polymerizability, environmental stability, high electrical conductivity, biocompatibility, and redox state dependent physico-chemical properties. Electrochemically prepared PPy is more interesting than the chemically prepared polymer because it adheres to the electrode surface and can be directly used for applications such as supercapacitors, electrochemical sensors, electromechanical actuators and drug delivery systems. In quest for improvement in quality of the device performances in the mentioned applications, micro and nano structured polymeric materials which bring in large surface area are studied. Finding a simple and efficient method of synthesis is very important for producing devices of PPy microstructures. Till date, Hard and soft template methods are the most employed methods for synthesis of these structures. Soft template based electrochemical methods are better than hard template methods to grow clean PPy microstructures on electrode substrates as procedures for removal of hard templates after the growth of microstructures are very complex. As per the literature, there is no unique method available to grow PPy microstructures which can demonstrate several applications. Although gas bubble based soft template methods are exploited to grow conducting polymer microstructures of sizes in few hundreds of micrometers, studies on applications of the same are limited. Hence it is planned to develop procedures to grow microstructures that can be used in several applications. In the current work, PPy microstructures with high coverage densities are synthesized on various electrode substrates by soft template based electrochemical techniques. Hollow, hemispherical and spherical PPy microstructures are developed by a two step method using electro generated hydrogen bubble templates on SS 304 electrodes. In the first step, Hydrogen bubbles are electro generated and stabilized on the electrode in the presence of β- naphthalene sulfonic acid (β-NSA). In the second step, Pyrrole is oxidised over the bubble template to form PPy microstructures. Microstructures (open and closed cups) of average size 15 μm are uniformly spread on the surface with a coverage density of 2.5×105 units /cm2. Globular PPy microstructures are developed by a single step method using concomitantly electro generated oxygen bubble templates on SS 304 electrodes during electropolymerization. Microstructures of average size 4 μm are uniformly spread on the surface with a coverage density of 7×105 units/cm2. Surfactant properties of Zwitterionic 4-(2-hydroxyethyl)-1-piperazine ethane sulfonic acid (HEPES) are exploited for the first time to grow conducting polymer microstructures. Ramekin shaped PPy microstructures are developed using HEPES as the surfactant to stabilize hydrogen bubble templates in a two step electrochemical synthesis method. Microramekins of size 100 µm are uniformly spread on the surface with a coverage density of 3000 units/cm2. Micropipettes and microhorns of PPy are synthesised by a single step electrochemical route using HEPES as a surfactant. Hollow micropipettes of length 7 µm with an opening of 200 nm at the top of the structure are observed. Similarly microhorn/celia structures are observed with length 10-15 µm. Microcelia are uniformly distributed over the surface with each structure having a diameter of 2 µm at the base to 150 nm at the tip. Growth mechanism based on contact angle of the reactant solution droplets on the substrate is proposed. PPy microstructures are characterized by scanning electron microscopy, X-Ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman Spectroscopy and UV-Visible spectroscopy to study morphology, ‘chemical bonding and structure’ , ‘defects and charge carriers’. Applicability of the electrodes with PPy microstructures in supercapacitors is investigated by cyclic voltammetry, chronopotentiometry and electrical impedance spectroscopy. Electrodes developed by all the above methods demonstrated very good supercapacitance properties. Supercapacitor studies revealed very high specific capacitances (580, 915, 728 and 922 F/g,) and specific powers (20, 25, 13.89 and 15.91 kW/kg) for electrodes with PPy microstructures (H2 bubble based two step method, O2 bubble based single step method, HEPES stabilized H2 bubbble method and HEPES based microhorn/celia structures respectively). Supercapacitive behavior of all the electrodes is retained even after an extended charge-discharge cycling in excess of 1500 cycles. Horseradish peroxidase entrapped, bowl shaped PPy microstructures are developed for H2O2 biosensing. Amperometric biosensor has a performance comparable to the sensors reported in the literature with high sensitivity value of 12.8 μA/(cm2.mM) in the range 1.0 mM to 10 mM. Glucose oxidase entrapped PPy amperometric biosensor is developed for Glucose sensing. Sensitivity of 1.29 mA/(cm2.mM) is observed for β-D-Glucose sensing in the 0.1 mM to 5.0 mM range while 58 μA/(cm2.mM) is observed in the 5.0 to 40 mM range. Potentiometric urea sensor with urease entrapped PPy microstructures on SS electrode is developed. It is able to sense urea in the micromolar ranges down to 0.1 μM. It represented an excellent performance with sensitivity of 27 mV/decade. Sensitivity in the micromolar range is 4.9 mV/(μM.cm2). Drug encapsulation and delivery is successfully demonstrated by two actuation means (i) by electrochemical actuation, (ii) by actuation based on pH changes. Concepts are proved by delivering a fluorescent dye into neutral and acidic solutions. Drug delivery is confirmed by UV-Visible spectroscopy and Fluorescence microscopy. Finally, Micro/nanostructures with Tangerine, Hollow globular (Pani Poori), Chip, Flake, Rose, Worm, Horn and Celia shapes are synthesized electrochemically and scanning electron microscopic studies are presented. Controlled growth of microstructures on lithographically patterned gold interdigital electrodes is demonstrated with a future goal of creating addressable microstructures. The studies reported in the thesis provide an insight on various applications of PPy microstructures (supercapacitors, sensors and drug delivery systems) developed by a unique methodology based on electrochemically generated gas bubble templates.

Le travail présenté dans cette thèse porte sur l'étude du dimensionnement d'une chaine de conversion électrique en entrainement direct d'un système direct de récupération de l'énergie des vagues (searev). Cette chaine de conversion est composée d'une génératrice synchrone à aimants permanents solidaire d'un volant pendulaire, d'un convertisseur électronique composé de deux ponts triphasés à modulation de largeur d'impulsion, l'un contrôlant la génératrice, l'autre permettant d'injecter l'énergie électrique au réseau. En complément, un système de stockage de l'énergie (batterie de supercondensateurs) est destiné au lissage de la puissance produite. Le dimensionnement de tous ces éléments constitutifs nécessite une approche d'optimisation sur cycle, dans un contexte de fort couplage multi-physique notamment entre les parties hydrodynamique et électromécanique. Dans un premier temps, l'ensemble génératrice-convertisseur, dont le rôle est d'amortir le mouvement d'un volant pendulaire interne, est optimisé en vue de minimiser le coût de production de l'énergie (coût du kWh sur la durée d'usage). Cette optimisation sur cycle est réalisée en couplage fort avec le système houlogénérateur grâce à la prise en compte conjointe de variables d'optimisation relatives à l'ensemble convertisseur-machine mais aussi à la loi d'amortissement du volant pendulaire. L'intégration d'une stratégie de défluxage, intéressante pour assurer un fonctionnement en écrêtage de la puissance, permet, dès l'étape de dimensionnement, de traiter l'interaction convertisseur-machine. Dans un second temps, la capacité énergétique du système de stockage de l'énergie fait l'objet d'une optimisation en vue de la minimisation de son coût économique sur cycle de vie. Pour ce faire, nous définissons des critères de qualité de l'énergie injectée au réseau, dont un lié au flicker, et nous comparons des stratégies de gestion de l'état de charge tout en tenant compte du vieillissement en cyclage des supercondensateurs dû à la tension et à leur température. Dans un troisième temps, à partir de données d'états de mer sur une année entière, nous proposons des dimensionnements de chaines de conversion électrique qui présentent les meilleurs compromis en termes d'énergie totale récupérée et de coût d'investissement. / The work presented in this thesis sets forth the study of the sizing of a direct-drive electrical conversion chain for a direct wave energy converter (SEAREV). This electrical chain is made up of a permanent magnet synchronous generator attached to a pendular wheel and a power-electronic converter made up of two three-phase pulse width modulation bridge, one controlling the generator, the other allowing injecting electrical energy into the grid. In addition, an energy storage system (bank of supercapacitors) is intended to smooth the power output. The sizing of all these components needs an operating cycle optimization approach, in a system context with strong multi-physics coupling, more particularly between hydrodynamical and electromechanical parts. At first, the generator-converter set, whose role is to damp the pendular movement of an internal wheel, is optimized with a view to minimize the cost of energy (kWh production cost). This optimization, based on torque-speed operating profiles, is carried out considering a strong coupling with the wave energy converter thanks to the consideration as design variables, some relatives to the generator-converter sizing but also some relatives to the damping law of the pendular wheel. In addition, the consideration of a flux-weakening strategy, interesting to ensure a constant power operation (levelling), allows, as soon as the sizing step, to deal with the generator-converter interaction. In a second step, the rated energy capacity of the energy storage system is being optimized with a view of the minimization of its economical life-cycle cost. To do this, we define quality criteria of the power output, including one related to the flicker, and we compare three energy managment rules while taking into account the power cycling aging of the supercapacitors due to the voltage and their temperature. In a third step, from yearly sea-states data, we provide sizings of the direct-drive electrical conversion chain that are the best trades-offs in terms of total electrical produced energy and economical investment cost.

The great popularity of portable, wearable, and implantable smart electronics has intensively boosted the development of flexible miniaturized power supplies. Owing to the fast charge/discharge capability, high power delivery, long cycling lifetime, easy fabrication and integration, flexible in-plane micro-supercapacitors (FPMSCs) are of significance as the micropower sources for the next-generation flexible on-chip electronics. In this review, we provide a comprehensive overview about FPMSCs and discuss the recent advances in their fabrication and applications. Particular emphasis is put on the emergent device fabrication technologies of FPMSCs, including deposition techniques, coating strategies, etching methods, and printing technologies. Moreover, we highlight the unique applications of FPMSCs in constructing smart responses and self-powered integrated systems in terms of multifunctional operation modes. Finally, the remaining challenges regarding flexibility, performance improvement, smart response, and microdevice integration of FPMSCs are discussed, which will stimulate further research in this thriving field.

In-plane micro-supercapacitors (MSCs), as promising power candidates for micro-devices, typically exhibit high power densities, large charge/discharge rates, and long cycling lifetimes. The high areal/volumetric capacitances, high energy/power densities, high rate capability, as well as flexibility are the main scientific pursue in recent years. Among diverse electrode materials for MSCs, coordination polymer frameworks are emerging due to the designable porous structure and tunable functionality. However, the unsatisfied electrochemical performance still hinders their practical applications. In this work, we demonstrate the first time an efficient in-situ growth approach to precisely modify the vacancy of Prussian-blue nano-thin films with pyridine by coordination reaction for high energy-density MSCs. Confirmed by the experimental results and density functional theory calculation, the vacancy modification within Prussian-blue network improved the film-forming property, hydrophilicity, and electrochemical activity of the thin films. The resultant MSCs based on pyridine-modified Prussian-blue exhibited an ultrahigh energy density of up to 12.1 mWh cm⁻³ and an ultra-low time constant (t₀) of 0.038 ms, which are the best values among the state-of-the-art in-plane MSCs. This work provides an attractive solution for structural engineering of promising active materials on molecule level toward high-performance micro-energy devices.

Объектом исследования являются электроды на основе нанотубулярного диоксида титана, модифицированные различными способами (термическая обработка, создание композитов с углеродными нанотрубками и частицами металлического никеля). Синтезированные образцы исследовались методом растровой электронной микроскопии и различными электрохимическими методами анализа (гальваностатический заряд-разряд, циклическая вольтамперометрия, импедансная спектроскопия). В результате исследования получены электроды: 1) Т/TiO2-НТ; 2) УНТ/TiO2-НТ; 3) Ni/TiO2-НТ представляющие собой: 1) массивы TiO2-НТ толщиной 3,5 мкм, с внутренним диаметром 70-80 нм и толщиной стенок 30-40 нм; 2) массивы TiO2-НТ с углеродными нанотрубками диаметром 10-30 нм и длиной от десятков нм до десятков мкм на поверхности оксидного слоя; 3) массивы TiO2-НТ, декорированные сферическими наночастицами Ni диаметром 70-100 нм с образованием локальных конгломератов частиц до 500 нм. Результаты работы позволили получить информацию об электрохимических характеристиках синтезированных электродов и преимуществах модификации структур TiO2-НТ для использования их в качестве электродов ионистров. / The object of this research is electrodes based on nanotubular titanium dioxide, modified by various methods (thermal treatment, synthesis of composites with carbon nanotubes and metallic nickel particles). The synthesized samples were investigated by scanning electron microscopy and various electrochemical analysis methods (galvanostatic charge-discharge, cyclic voltammetry, impedance spectroscopy). As a result of the study, were obtained: 1) T/TiO2-NT; 2) CNT/TiO2-NT; 3) Ni/TiO2-NT electrodes, which are: 1) arrays of TiO2-NT 3.5 μm thick, with an inner diameter of 70-80 nm and wall thickness 30-40 nm; 2) arrays of TiO2-NT with carbon nanotubes with a diameter of 10-30 nm and a length from tens of nm to tens of microns on the surface of the oxide layer; 3) arrays of TiO2-NT, decorated with spherical Ni nanoparticles with a diameter of 70-100 nm with the formation of local conglomerates of particles up to 500 nm. The results of the work made it possible to obtain information on the electrochemical characteristics of the synthesized electrodes and the advantages of modifying the TiO2-NT structures to use them as supercapacitor electrodes.

Dans un contexte de progression du stockage d’énergie sous forme électrochimique dans les transports, notamment dans l’aéronautique, les problématiques de performance, de fiabilité, de sureté de fonctionnement et de durée de vie du stockeur sont essentielles pour utilisateurs. Cette thèse se focalise ces voltes pour l’avion plus électrique. Les technologies étudiées correspondent à des éléments commerciaux de dernière génération de type Lithium-ion (NMC/graphite+SiO, NCA/graphite, LFP/graphite, NMC/LTO), Lithium-Soufre (Li-S), supercondensateur et hybride (LiC). Une première partie de ce manuscrit s’attache à la quantification des performances des différents éléments dans l’environnement aéronautique [-20°C, 55°C] et pour l’usage aéronautique. Un modèle comportemental de type électro-thermique est développé et validé. La seconde partie est consacrée à la quantification du vieillissement des différents éléments. Les résultats de vieillissement calendaire et en cyclage actif sont présentés ainsi que ceux des tests abusifs. Une méthode d’estimation de l’état de santé (SOH) des éléments basés sur l’analyse de la capacité incrémentale (ICA) est proposée. Enfin, l’évaluation de la robustesse des éléments de stockage lors de tests de vieillissement accéléré avec un profil spécifique à l’usage aéronautique est proposé. Les modèles de vieillissement et la méthode d'estimation de SOH proposés précédemment sont utilisés ici pour évaluer l'impact de la température sur la vitesse de dégradation et pour estimer le SOH des cellules vieillies à l’aide de ce profil aéronautique. / In the context of progress in the electrochemical energy storage systems in the transport field, especially in the aeronautics, the issues of performance, reliability, safety and robustness of these elements are essential for users. This thesis is focused on these issues for the more electric aircraft. The technologies studied correspond to the latest generation commercial elements of Lithium-ion batteries (NMC/ graphite + SiO, NCA/graphite, LFP/graphite, NMC/LTO), Lithium-Sulfur (Li-S), Supercapacitor and Lithium-ion capacitors. The first part of this manuscript is dedicated to the performance quantification of the different electrochemical energy storage elements in aeronautical environment [-20°C, 55°C] and usage. An efficient and accurate electro-thermal model is developed and validated. The second part is devoted to the calendar and power cycling ageings as well as to the presentation of abuse testing results. A State Of Health (SOH) estimation based on incremental capacity analysis method is proposed. Finally, the robustness of the storage elements during accelerated ageing tests with a specific profile for the aeronautical usage is evaluated. The ageing models and SOH estimation methods proposed in the previous sections are used here to evaluate the impact of temperature on the degradation rate and to estimate the SOH of the cells with this aeronautical profile.

Les travaux réalisés dans le cadre de cette thèse ont porté sur la réalisation de matériaux composites nanostructurés à base de nanotubes de carbone verticalement alignés (NTC alignés) et de polymères π-conjugués en vue de leur utilisation en tant que matériaux d’électrodes dans des dispositifs de stockage d’énergie de type supercondensateurs. Dans une première partie, les travaux se sont focalisés sur la croissance par CVD d’aérosol de NTC sur des substrats d’acier inoxydable via le dépôt préalable d’une sous-couche céramique SiOx. Grâce à l’optimisation de ce procédé, des tapis de NTC longs, denses et alignés pouvant directement servir de supports à l’électrodépôt de polymères π-conjugués ont pu être obtenus. Dans une seconde partie, les travaux se sont concentrés sur l’électrodépôt de poly(3-méthylthiophène) (P3MT) en milieu liquide ionique EMITFSI sur les tapis de NTC alignés à partir d’une méthode chronopotentiométrique « séquencée » permettant de réaliser des dépôts homogènes dans la profondeur des tapis. Une composition massique optimale de 70 % de P3MT permettant d’atteindre des capacitances spécifiques de 170 F.g-1 de polymère tout en conservant des cinétiques de charge-décharges élevées, comparativement à des composites NTC/P3MT enchevêtrés, a pu être déterminée. A partir des matériaux composites optimisés, des dispositifs symétriques NTC/P3MT // P3MT/NTC et hybrides CA // P3MT/NTC ont été assemblés. Le dispositif hybride à notamment permis d’atteindre une tension de 2,7 V et une capacitance de système de 26 F.g-1 en milieu EMITFSI à 25 °C. Par ailleurs, une énergie maximale de 23 Wh.kg-1 et une puissance maximale de 6,9 kW.kg-1 ont été obtenues avec une perte de seulement 7 % après 4000 cycles. Pour finir, l’électrodépôt de polypyrrole (Ppy) a été étudié dans différents milieux liquides ioniques protiques et aprotiques. Après des études réalisées par microbalance à cristal de quartz permettant de mieux comprendre les mécanismes d’insertion des espèces ioniques lors de la croissance du polymère conjugué et lors de son dopage positif réversible, des dépôt de Ppy ont été réalisés et optimisés dans la profondeur des tapis de NTC alignés. Des nanocomposites NTC alignés/Ppy présentant des capacitances spécifiques comprises entre 100 et 130 F.g-1 ont ainsi pu être obtenus. / This thesis focused on the elaboration of nanostructured composite materials based on vertically aligned carbon nanotubes (aligned CNT) and π-conjugated polymers and their use as electrode materials in supercapacitor-type energy storage devices. The first part focused on aligned CNT growth by aerosol-assisted CVD on stainless steel substrates and the deposition of a SiOx ceramic sublayer. Thanks to the optimization of this growth process, long, dense, and aligned CNT carpets which can directly act as support for the electrodeposition of π-conjugated polymers were obtained. The second part focused on the electrodeposition of poly (3-methylthiophene) (P3MT) in EMITFSI ionic liquid medium on aligned CNT carpets using a “pulsed” chronopotentiometric method to produce homogeneous deposits in the depth of the carpets. An optimal P3MT mass composition of 70 %, which helped achieve a specific capacitance of 170 F.g-1 of polymer while maintaining high charge-discharge kinetics, compared with NTC/P3MT entangled composites, was determined. NTC/P3MT // P3MT/NTC symmetrical devices and CA // P3MT/NTC hybrid devices were assembled using the optimized composite materials. The hybrid device reached a voltage of 2.7 V and a system capacitance of 26 F.g-1 in EMITFSI at 25 ° C. Furthermore, a maximum energy of 23 Wh.kg-1 and a maximum power of 6.9 kW.kg-1 were obtained with only a 7 % loss after 4000 cycles. Finally, the electrodeposition of polypyrrole (Ppy) was investigated in different protic and aprotic ionic liquids. After quartz crystal microbalance studies in order to better understand the insertion mechanisms of ionic species during conjugated polymer growth and during its reversible positive doping, the electrodeposition of Ppy within the deepness of the aligned CNT carpets was optimized. Aligned CNT/Ppy nanocomposites with specific capacitances ranging between 100 and 130 F.g-1 were obtained.