Littérature scientifique sur le sujet « Hybrid cathodes »
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Articles de revues sur le sujet "Hybrid cathodes"
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Yamada, Mitsuru, Mika Fukunishi et Futoshi Matsumoto. « Improvement in Rate Capabilities of Hybrid Cathodes with through-Holed Layers of Cathode Material and Activated Carbon on Each Side of a Current Collector in Lithium-Ion Batteries ». ECS Meeting Abstracts MA2024-02, no 67 (22 novembre 2024) : 4550. https://doi.org/10.1149/ma2024-02674550mtgabs.
Texte intégralRésumé :
This study was conducted to improve the rate capability and cyclability of cathodes for lithium-ion batteries (LIBs) with hybrid cathode structure. Through-holed LIB cathode material and activated carbon layers formed on each side of a current collector were drilled with a picosecond pulsed laser beam for preparing the cathode structure (Figure). The hybrid cathodes exhibited excellent rate capabilities of 93% capacity retention at 100 C. The results were dependent on the weight percentage of the activated carbon relative to the total weight of the active materials and on the difference in discharge/charge voltages between the LIB cathode and activated carbon materials. The cathode could have cycle stability at 50 C during 100 cycles. The performance characteristics of the hybrid cathode, the through-holed and nontreated LIB cathodes and the nontreated activated carbon cathodes were compared in a Ragone plot. In the plot, the hybrid cathode was located in the region where conventional through-holed and nontreated cathodes could not be located. Figure 1
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Dolphijn, Guillaume, Fernand Gauthy, Alexandru Vlad et Jean-François Gohy. « High Power Cathodes from Poly(2,2,6,6-Tetramethyl-1-Piperidinyloxy Methacrylate)/Li(NixMnyCoz)O2 Hybrid Composites ». Polymers 13, no 6 (23 mars 2021) : 986. http://dx.doi.org/10.3390/polym13060986.
Texte intégralRésumé :
Lithium-ion batteries are today among the most efficient devices for electrochemical energy storage. However, an improvement of their performance is required to address the challenges of modern grid management, portable technology, and electric mobility. One of the most important limitations to solve is the slow kinetics of redox reactions associated to inorganic cathodic materials, directly impacting on the charging time and the power characteristics of the cells. In sharp contrast, redox polymers such as poly(2,2,6,6-tetramethyl-1-piperidinyloxy methacrylate) (PTMA) exhibit fast redox reaction kinetics and pseudocapacitors characteristics. In this contribution, we have hybridized high energy Li(NixMnyCoz)O2 mixed oxides (NMC) with PTMA. In this hybrid cathode configuration, the higher voltage NMC (ca. 3.7 V vs. Li/Li+) is able to transfer its energy to the lower voltage PTMA (3.6 V vs. Li/Li+) improving the discharge power performances and allowing high power cathodes to be obtained. However, the NMC-PTMA hybrid cathodes show an important capacity fading. Our investigations indicate the presence of an interface degradation reaction between NMC and PTMA transforming NMC into an electrochemically dead material. Moreover, the aqueous process used here to prepare the cathode is also shown to enable the degradation of NMC. Indeed, once NMC is immersed in water, alkaline surface species dissolve, increasing the pH of the slurry, and corroding the aluminum current collector. Additionally, the NMC surface is altered due to delithiation which enables the interface degradation reaction to take place. This reaction by surface passivation of NMC particles did not succeed in preventing the interfacial degradation. Degradation was, however, notably decreased when Li(Ni0.8Mn0.1Co0.1)O2 NMC was used and even further when alumina-coated Li(Ni0.8Mn0.1Co0.1)O2 NMC was considered. For the latter at a 20C discharge rate, the hybrids presented higher power performances compared to the single constituents, clearly emphasizing the benefits of the hybrid cathode concept.
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Evans, John Parker, Dominic F. Gervasio et Barry M. Pryor. « A Hybrid Microbial–Enzymatic Fuel Cell Cathode Overcomes Enzyme Inactivation Limits in Biological Fuel Cells ». Catalysts 11, no 2 (11 février 2021) : 242. http://dx.doi.org/10.3390/catal11020242.
Texte intégralRésumé :
The construction of optimized biological fuel cells requires a cathode which combines the longevity of a microbial catalyst with the current density of an enzymatic catalyst. Laccase-secreting fungi were grown directly on the cathode of a biological fuel cell to facilitate the exchange of inactive enzymes with active enzymes, with the goal of extending the lifetime of laccase cathodes. Directly incorporating the laccase-producing fungus at the cathode extends the operational lifetime of laccase cathodes while eliminating the need for frequent replenishment of the electrolyte. The hybrid microbial–enzymatic cathode addresses the issue of enzyme inactivation by using the natural ability of fungi to exchange inactive laccases at the cathode with active laccases. Finally, enzyme adsorption was increased through the use of a functionally graded coating containing an optimized ratio of titanium dioxide nanoparticles and single-walled carbon nanotubes. The hybrid microbial–enzymatic fuel cell combines the higher current density of enzymatic fuel cells with the longevity of microbial fuel cells, and demonstrates the feasibility of a self-regenerating fuel cell in which inactive laccases are continuously exchanged with active laccases.
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Zhu, Sheng, et Yan Li. « Carbon-metal oxide nanocomposites as lithium-sulfur battery cathodes ». Functional Materials Letters 11, no 06 (décembre 2018) : 1830007. http://dx.doi.org/10.1142/s1793604718300074.
Texte intégralRésumé :
In rechargeable lithium-sulfur (Li-S) batteries, the conductive carbon materials with high surface areas can greatly enhance the electrical conductivity of sulfur cathode, and metal oxides can restrain the dissolution of lithium polysulfides within the electrolyte through strong chemical bindings. The rational design of carbon-metal oxide nanocomposite cathodes has been considered as an effective solution to increase the sulfur utilization and improve cycling performance of Li-S batteries. Here, we summarize the recent progresses in the carbon-metal oxide composites for Li-S battery cathodes. Some insights are also offered on the future directions of carbon-metal oxide hybrid cathodes for high performance Li-S batteries.
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Du, Leilei, Xu Hou, Debbie Berghus, Richard Schmuch, Martin Winter, Jie Li et Tobias Placke. « Failure Mechanism of LiNi0.6Co0.2Mn0.2O2 Cathodes in Aqueous/Non-Aqueous Hybrid Electrolytes ». ECS Meeting Abstracts MA2022-01, no 55 (7 juillet 2022) : 2276. http://dx.doi.org/10.1149/ma2022-01552276mtgabs.
Texte intégralRésumé :
The urgent need for higher energy density of aqueous Li-ion batteries (ALBs) cannot only be satisfied by electrolyte modifications, the utilization of layered oxide cathodes is another efficient strategy, and particularly Li[NixCoyMn1-x-y]O2 (NCM) materials are of high interest due to their high specific capacities. Concerning the H+-Li+ exchange side reaction of layered cathode in water solution, however, whether proton contamination degrades NCM-type cathodes in highly-concentrated aqueous electrolyte is an unclear but meaningful point. In this work, the underlying mechanisms responsible for degradation of NCM622 | aqueous/non-aqueous hybrid electrolyte |TiO2/LiTi2(PO4)3 (P/N=1.2:1) full-cells are explored by comprehensive studies involving in the evolution of electrochemical impendence and lattice structure changes after cycling within different operating voltage ranges. It is found that proton co-intercalation into the layered structure still takes place in high concentration aqueous/non-aqueous hybrid electrolytes, and the NCM622 cathode quickly shows degradation after being charged to higher cut-off voltage owing to severe protonation. The introduced proton can increase the diffusion barrier for Li+ ions, which in turn hinders lithiation of the de-lithiated cathode.
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Amine, Khalil. « (Invited) Advances in Lithium-Ion Battery for Enabling Mass Electrification of Vehicles ». ECS Meeting Abstracts MA2024-02, no 7 (22 novembre 2024) : 896. https://doi.org/10.1149/ma2024-027896mtgabs.
Texte intégralRésumé :
To meet the high-energy requirement that can enable the 40-miles electric drive Plug in Hybrid Electric Vehicle (P-HEVs), long range electric vehicle (EV) and smart grid, it is necessary to develop very high energy and high-power cathodes and anodes that when combined in a battery system must offer over 5,000 charge-depleting cycles, 15 years calendar life as well as excellent abuse tolerance. These challenging requirements make it difficult for conventional battery systems to be adopted in P-HEVs and EVs. In this talk, we will first introduce the next generation lithium-ion battery cathode design that include Ni-rich full concentration gradient cathode with Nano-rode primary particles, a novel advance PEDOT coating on both secondary and primary cathode particles that significantly enhance the cycle life at high voltages, and an epitaxial entropy-assisted coating that can suppress strain propagation in ultrahigh-Ni (≥90%) cathodes during fast charging. We will then describe a novel silicon-graphene composite anode including a novel pre-lithiation technology to overcome the irreversible loss of this anode in the first cycle. We will also present novel fluorinated based electrolyte design strategies that can stabilize Ni-rich cathodes at high-voltage as well as lithium metal anode to achieve high energy density and long cycle life.
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Hu, Xue, Zi Lin, Li Liu, Jian Huai et Hua Deng. « Effects of the LiFePO4 content and the preparation method on the properties of (LiFePO4+AC)/Li4Ti5O12 hybrid batterycapacitors ». Journal of the Serbian Chemical Society 75, no 9 (2010) : 1259–69. http://dx.doi.org/10.2298/jsc091228105h.
Texte intégralRésumé :
Two composite cathode materials containing LiFePO4 and activated carbon (AC) were synthesized by an in-situ method and a direct mixing technique, which are abbreviated as LAC and DMLAC, respectively. Hybrid battery-capacitors LAC/Li4Ti5O12 and DMLAC/Li4Ti5O12 were then assembled. The effects of the content of LiFePO4 and the preparation method on the cyclic voltammograms, the rate of charge-discharge and the cycle performance of the hybrid batterycapacitors were investigated. The results showed the overall electrochemical performance of the hybrid battery-capacitors was the best when the content of LiFePO4 in the composite cathode materials was in the range from 11.8 to 28.5 wt. %, while the preparation method had almost no impact on the electrochemical performance of the composite cathodes and hybrid battery-capacitors. Moreover, the hybrid batterycapacitor devices had a good cycle life performance at high rates. After 1000 cycles, the capacity loss of the DMLAC/Li4Ti5O12 hybrid batterycapacitor device at 4 C was no more than 4.8 %. Moreover, the capacity loss would be no more than 9.6 % after 2000 cycles at 8?C.
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Proffit, Danielle L., Albert L. Lipson, Baofei Pan, Sang-Don Han, Timothy T. Fister, Zhenxing Feng, Brian J. Ingram, Anthony K. Burrell et John T. Vaughey. « Reducing Side Reactions Using PF6-based Electrolytes in Multivalent Hybrid Cells ». MRS Proceedings 1773 (2015) : 27–32. http://dx.doi.org/10.1557/opl.2015.590.
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ABSTRACTThe need for higher energy density batteries has spawned recent renewed interest in alternatives to lithium ion batteries, including multivalent chemistries that theoretically can provide twice the volumetric capacity if two electrons can be transferred per intercalating ion. Initial investigations of these chemistries have been limited to date by the lack of understanding of the compatibility between intercalation electrode materials, electrolytes, and current collectors. This work describes the utilization of hybrid cells to evaluate multivalent cathodes, consisting of high surface area carbon anodes and multivalent nonaqueous electrolytes that are compatible with oxide intercalation electrodes. In particular, electrolyte and current collector compatibility was investigated, and it was found that the carbon and active material play an important role in determining the compatibility of PF6-based multivalent electrolytes with carbon-based current collectors. Through the exploration of electrolytes that are compatible with the cathode, new cell chemistries and configurations can be developed, including a magnesium-ion battery with two intercalation host electrodes, which may expand the known Mg-based systems beyond the present state of the art sulfide-based cathodes with organohalide-magnesium based electrolytes.
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Ramirez-Meyers, Katrina, et Elizabeth C. Dickey. « A TEM Study of Structural Degradation in LiFePO4 Batteries after Hybrid Vehicle Use ». ECS Meeting Abstracts MA2024-01, no 2 (9 août 2024) : 369. http://dx.doi.org/10.1149/ma2024-012369mtgabs.
Texte intégralRésumé :
Establishing a robust, efficient circular economy for batteries hinges on understanding how they decay over time under various conditions. This understanding is crucial to maximize material use before recycling or disposal. A key aspect of this endeavor is the study of lithium iron phosphate (LiFePO4), a pivotal battery technology whose structural integrity over time remains a subject of inquiry.1 Known aging mechanisms in LiFePO4 (LFP) batteries include electrode degradation, SEI growth, and electrolyte decomposition.1 These processes extend to the cathode, where degradation can manifest as Fe dissolution, Li inventory loss, Fe/Li anti-site defects, and LFP amorphization.1–3 However, these mechanisms are typically studied in lab-aged cells under controlled conditions, leaving a gap in our understanding of their behavior in real-life, commercialized applications. Our research aims to bridge this gap by characterizing the degradation mechanisms of LFP cathode material in various states of health (SOH) after use in a hybrid vehicle. We sourced our cathode samples from 26650 cells extracted from a BAE ESS-A123 hybrid bus battery pack. After selecting cells with drastically different SOHs based on previous analyses,4 we employed transmission electron microscopy (TEM) for detailed characterization. In this talk, we will share insights gained from high-resolution TEM characterization, alongside chemical analysis using energy-filtered TEM and electron energy loss spectroscopy (EELS). Our focus will be on changes in the olivine structure, including lattice parameter alterations, Li and Fe migration, and Fe oxidation. By combining cell-level SOH analyses with TEM characterization, we will highlight how electrochemical test results correlate with material degradation mechanisms, enhancing our understanding of battery health, longevity, and diagnostics. Wang, L. et al. Insights for understanding multiscale degradation of LiFePO4 cathodes. eScience 2, 125–137 (2022). Li, X. et al. First Atomic-Scale Insight into Degradation in Lithium Iron Phosphate Cathodes by Transmission Electron Microscopy. J. Phys. Chem. Lett. 11, 4608–4617 (2020). Xu, P. et al. Efficient Direct Recycling of Lithium-Ion Battery Cathodes by Targeted Healing. Joule 4, 2609–2626 (2020). Ramirez-Meyers, K., Rawn, B. & Whitacre, J. F. A statistical assessment of the state-of-health of LiFePO4 cells harvested from a hybrid-electric vehicle battery pack. J. Energy Storage 59, 106472 (2023).
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Omenya, Fredrick, Xiaolin Li et David Reed. « (Invited) Insights into the Effects of Doping on Structural Phase Evolution of Sodium Nickel Manganese Oxide Cathodes for High-Energy Sodium Ion Batteries ». ECS Meeting Abstracts MA2023-01, no 5 (28 août 2023) : 939. http://dx.doi.org/10.1149/ma2023-015939mtgabs.
Texte intégralRésumé :
High-performance and low-cost transition metal (TM) layered oxides using earth abundant elements are promising cathodes for Na-ion batteries. However, it is challenging to obtain desired materials because the large Na size, different Na occupations and various layer stacking sequences multiply the complication in determining the structure of a given composition and exacerbate uncertainty to the structure-property correlation. In this work, we use the attainment of desired NaxMnyNizTM1−y-zO2-based cathode materials as model compound to demonstrate a general roadmap for batch development of sodium layered cathodes towards practical applications. Several cost-effective O3 and P2/O3 hybrid cathode materials have been obtained, all of which demonstrate excellent performance. Acknowledgement: This work is supported by the U.S. Department of Energy (DOE) Office of Electricity under contract No. 57558. PNNL is operated by Battelle Memorial Institute for the DOE under contract DE-AC05-76RL01830
Thèses sur le sujet "Hybrid cathodes"
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Adjez, Yanis. « Stimulation of Electrocatalytic Reduction of Nitrate by Immobilized Ionic Liquids ». Electronic Thesis or Diss., Sorbonne université, 2024. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2024SORUS337.pdf.
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La pollution de l'eau par les nitrates représente un défi environnemental majeur et constitue l'une des dix violations les plus courantes de la qualité de l'eau dans le monde. Ce défi offre une opportunité pour l'économie circulaire, car l'électrolyse des nitrates a été proposée comme une méthode durable pour la valorisation des effluents contaminés par les nitrates grâce à la production décentralisée et simultanée d'ammoniac (un produit chimique de base). En particulier, la réduction électrochimique des nitrates (REN) est une stratégie prometteuse et durable pour résoudre le problème critique de la pollution des sources d'eau par les nitrates. Plusieurs matériaux abondants sur Terre, tels que le cuivre et l'étain, ont été proposés comme matériaux électrocatalytiques adaptés pour la REN. Jusqu'à présent, la plupart des études électrochimiques fondamentales ont été menées dans des conditions potentiostatiques. En revanche, cette étude présente une évaluation de la REN dans des conditions galvanostatiques pour atteindre des conditions opérationnelles plus représentatives pour des systèmes ingénierisés de plus grande envergure. Cependant, cela provoque l'apparition de la réaction concomitante de dégagement de l'hydrogène (HER), qui se produit à un potentiel thermodynamique similaire à celui de la REN. Ainsi, l'efficacité faradique de la REN diminue considérablement dans des conditions galvanostatiques réalistes en raison de la concurrence avec la HER. Ce projet aborde ce défi fondamental en électrocatalyse et propose une nouvelle stratégie basée sur l'immobilisation de molécules ioniques à base d'imidazolium sur la surface de la cathode pour inhiber sélectivement la HER et améliorer la REN. Notamment, cette recherche explore une gamme de matériaux de cathodiques hybrides, y compris des électrodes à base de carbone et de métal sous forme de plaques 2D et de mousses 3D, reconnues pour leur potentiel dans les applications réelles de la REN. Le succès de l'immobilisation de la couche organique ionique sur les cathodes a été confirmé par différentes techniques de caractérisation physico-chimiques et par une évaluation subséquente de l'activité et de la sélectivité électrocatalytiques, démontrant une sélectivité et une efficacité faradique améliorées pour la production d'ammoniac sur les cathodes hybrides, deux fois supérieures à celles du matériau d'électrode nu pour la REN dans les mêmes conditions expérimentalesNitrate pollution in water represents a significant environmental challenge and is one of the top ten most common water quality violations worldwide. This challenge offers an opportunity for the circular economy as nitrate electrolysis has been suggested as a sustainable method for valorization of nitrate-contaminated effluents by simultaneous decentralized ammonia production (a commodity chemical). In particular, the electrochemical reduction of nitrate (ERN) is a promising and sustainable strategy for addressing the critical issue of nitrate pollution in water sources. Several earth abundant materials such as copper and tin have been suggested as suitable electrocatalytic materials for ERN. Mostly fundamental electrochemical studies under potentiostatic conditions are reported so far. In contrast, this study presents ERN evaluation under galvanostatic conditions for achieving more representative operational conditions for larger engineered systems. However, this provokes the appearance of the concomitant hydrogen evolution reaction (HER), which takes place at a similar thermodynamic potential than ERN. Thus, faradaic efficiency for ERN significantly diminishes under realistic galvanostatic conditions due to the competition with HER. This project addresses this fundamental challenge in electrocatalysis and proposes a novel strategy based on the immobilization of imidazolium-based ionic molecules on the surface of the cathode to selectively inhibit HER and enhance ERN. Notably, this research explores a range of hybrid cathode materials, including 2D plate and 3D foam carbon- and metal-based electrodes, which are recognized for their potential in real world applications for ERN. The success of the ionic organic layer immobilization onto the cathodes was confirmed through different physicochemical characterization techniques and subsequent electrocatalytic activity and selectivity evaluation, which demonstrated an enhanced selectivity and faradaic efficiency for ammonia production on hybrid cathodes twice as much as the bare electrode material for ERN under the same experimental conditions
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Moraw, Franz Christian. « Hybrid PEM fuel cell : redox cathode approach ». Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/7720.
Texte intégralRésumé :
The proton exchange membrane fuel cell (PEMFC) is considered to be a
promising power device with a broad range of applications. However, there are still a
number of challenges especially concerning performance, cost, and reliability of these
systems. The redox flow battery utilizes fundamentally simpler chemistry, but has
limitations in terms of membranes/materials used in system construction and in terms of
redox regeneration requirements.
The hybridization of a PEMFC anode with a redox flow battery cathode,
replacing the limiting oxygen electrode, leads to both advantages and compromises in
performance. Although there are improvements in kinetics, cell and systems design, and
cost, there are restrictions imposed by the regeneration method and membrane
contamination. In this work, the Fe³⁺/Fe²⁺ redox fuel cell cathode is characterized over a
range of electrolyte concentrations, operating conditions, and electrode materials. A
Fe³⁺/Fe²⁺ simulated bio-electrolyte and a
simple electrolyte catholyte are studied using
CV and ETS to determine kinetic parameters for the electrolyte cathode redox couple,
while a prototype single cell fuel cell is used to demonstrate actual fuel cell performance.
Electrochemical data shows the effect of ferric ion complexation! polymerization
on the operation of both electrolyte systems. The results show that the heterogeneous
electron transfer rate constant and diffusion coefficient as well as interface properties all
increase with the ratio of total anion species (S0₄²⁻,HS0₄⁻)to ferric species. Fuel cell
testing showed no significant difference in performance between the two systems
opening up various possibilities for redox species regeneration. Improvements are also
achieved through optimization of cathode materials and operating conditions.
This hybrid system, part of a strategic NSERC grant (Novel biofuel cell - methane
reforming reactor system for electricity generation, #GHGPJ 269967 — 03)(1), showed
promising performance even though components such as the membrane were not
optimized. Power densities of greater than 0.25 W/cm² were achieved with no platinum
group metals on the cathode. In addition, the liquid redox cathode eliminates the need for
external humidification and separate cooling for the fuel cell and provides greater design
flexibility. Different aspects of the redox cathode were characterized and showed
opportunity for further performance improvement.
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Gustavsson, Lars-Erik. « Hollow Cathode Deposition of Thin Films ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6925.
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Osiecki, Tomasz, Colin Gerstenberger, Holger Seidlitz, Alexander Hackert et Lothar Kroll. « Behavior of Cathodic dip Paint Coated Fiber Reinforced Polymer/Metal Hybrids ». Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-175536.
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Increasing mechanical, economic and environmental requirements lead to multi material designs, wherein different classes of materials and manufacturing processes are merged to realize lightweight components with a high level of functional integration. Particularly in automotive industry the use of corresponding technologies will rise in the near future, as they can provide a significant contribution to weight reduction, energy conservation and therefore to the protection of natural resources. Especially the use of continuous fiber reinforced polymers (FRP) with thermoplastic matrices offers advantages for automotive components, due to its good specific characteristics and its suitability for mass production. In conjunction with isotropic materials, such as steel or aluminum, optimized lightweight structures can be produced, whose properties can be easily adapted to the given component requirements.
The present paper deals with the development of innovative hybrid laminates with low residual stresses, made of thin-walled steel sheets and glass fiber reinforced thermoplastic (GFRP) prepregs layers. Thereby the interlaminar shear strength (ILSS) was increased by an optimization of the FRP/metal-interfaces, carried out by examining the influence of several pre-operations like sanding, cleaning with organic solvents and applying primer systems. Based on these findings optimized compound samples were prepared and tested under realistic Cathodic dip paint conditions to determine the influence on the ILSS.
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Ezzedine, Mariam. « Fabrication of hierarchical hybrid nanostructured electrodes based on nanoparticles decorated carbon nanotubes for Li-Ion batteries ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX105/document.
Texte intégralRésumé :
Cette thèse est consacrée à la fabrication ascendante (bottom-up) de matériaux nanostructurés hybrides hiérarchisés à base de nanotubes de carbone alignés verticalement (VACNTs) décorés par des nanoparticules (NPs). En fonction de leur utilisation comme cathode ou anode, des nanoparticules de soufre (S) ou silicium (Si) ont été déposées. En raison de leur structure unique et de leurs propriétés électroniques, les VACNTs agissent comme une matrice de support et un excellent collecteur de courant, améliorant ainsi les voies de transport électroniques et ioniques. La nanostructuration et le contact du S avec un matériau hôte conducteur améliore sa conductivité, tandis que la nanostructuration du Si permet d'accommoder plus facilement les variations de volume pendant les réactions électrochimiques. Dans la première partie de la thèse, nous avons synthétisé des VACNTs par une méthode de dépôt chimique en phase vapeur (HF-CVD) directement sur des fines feuilles commerciales d'aluminium et de cuivre sans aucun prétraitement des substrats. Dans la deuxième partie, nous avons décoré les parois latérales des VACNTs avec différents matériaux d'électrode, dont des nanoparticules de S et de Si. Nous avons également déposé et caractérisé des nanoparticules de nickel (Ni) sur les VACNTs en tant que matériaux alternatifs pour l'électrode positive. Aucun additif conducteur ou aucun liant polymère n'a été ajouté à la composition d'électrode. La décoration des nanotubes de carbone a été effectuée par deux méthodes différentes: méthode humide par électrodéposition et méthode sèche (par dépôt physique en phase vapeur (PVD) ou par CVD). Les structures hybrides obtenues ont été testées électrochimiquement séparément dans une pile bouton contre une contre-électrode de lithium. A notre connaissance, il s'agit de la première étude de l'évaporation du soufre sur les VACNTs et de la structure résultante (appelée ici S@VACNTs). Des essais préliminaires sur les cathodes nanostructurées obtenues (S@VACNTs revêtus d'alumine ou de polyaniline) ont montré qu'il est possible d'atteindre une capacité spécifique proche de la capacité théorique du soufre. La capacité surfacique de S@VACNTs, avec une masse de S de 0.76 mg cm-2, à un régime C/20 atteint une capacité de 1.15 mAh cm-2 au premier cycle. Pour les anodes nanostructurées au silicium (Si@VACNTs), avec une masse de Si de 4.11 mg cm-2, on montre une excellente capacité surfacique de 12.6 mAh cm-2, valeur la plus élevée pour les anodes à base de silicium nanostructurées obtenues jusqu'à présent. Dans la dernière partie de la thèse, les électrodes nanostructurées fabriquées ont été assemblées afin de réaliser la batterie complète (Li2S/Si) et sa performance électrochimique a été testée. Les capacités surfaciques obtenues pour les électrodes nanostructurées de S et de Si ouvrent la voie à la réalisation d'une LIB à haute densité d'énergie, entièrement nanostructurée, et démontrent le grand potentiel du concept proposé à base d'électrodes nanostructurées hybrides hiérarchiséesThis thesis is devoted to the bottom-up fabrication of hierarchical hybrid nanostructured materials based on active vertically aligned carbon nanotubes (VACNTs) decorated with nanoparticles (NPs). Owing to their unique structure and electronic properties, VACNTs act as a support matrix and an excellent current collector, and thus enhance the electronic and ionic transport pathways. The nanostructuration and the confinement of sulfur (S) in a conductive host material improve its conductivity, while the nanostructuration of silicon (Si) accommodates better the volume change during the electrochemical reactions. In the first part of the thesis, we have synthesized VACNTs by a hot filament chemical vapor deposition (HF-CVD) method directly over aluminum and copper commercial foils without any pretreatment of the substrates. In the second part, we have decorated the sidewalls and the surface of the VACNT carpets with various LIB's active electrode materials, including S and Si NPs. We have also deposited and characterized nickel (Ni) NPs on CNTs as alternative materials for the cathode electrode. No conductive additives or any polymer binder have been added to the electrode composition. The CNTs decoration has been done systematically through two different methods: wet method by electrodeposition and dry method by physical vapor deposition (PVD). The obtained hybrid structures have been electrochemically tested separately in a coin cell against a lithium counter-electrode. Regarding the S evaporationon VACNTs, and the S@VACNTs structure, these topics are investigated for the first time to the best of our knowledge.Preliminary tests on the obtained nanostructured cathodes (S@VACNTs coated with alumina or polyaniline) have shown that it is possible to attain a specific capacity close to S theoretical storage capacity. The surface capacity of S@VACNTs, with 0.76 mg cm-2 of S, at C/20 rate reaches 1.15 mAh cm-2 at the first cycle. For the nanostructured anodes Si@VACNTs, with 4.11 mg cm-2 of Si showed an excellent surface capacity of 12.6 mAh cm-2, the highest value for nanostructured silicon anodes obtained so far. In the last part of the thesis, the fabricated nanostructured electrodes have been assembled in a full battery (Li2S/Si) and its electrochemical performances experimentally tested. The high and well-balanced surface capacities obtained for S and Si nanostructured electrodes pave the way for realization of high energy density, all-nanostructured LIBs and demonstrate the large potentialities of the proposed hierarchical hybrid nanostructures' concept
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Holmes, Steven. « An investigation into the practical and theoretical aspects of hybrid cathodic protection ». Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/12280.
Texte intégralRésumé :
Galvanic anode technology has in recent years come to the fore as a cost-effective method of successfully mitigating the corrosion of reinforcing steel in concrete structures. Developments in the field of cathodic protection have included the introduction of a novel Hybrid anode system, which uses the same sacrificial anode to pass a short-term impressed current before being connected to the steel directly to provide a long-term galvanic current. Galvanic and hybrid technologies are often seen as less powerful solutions in the treatment of reinforcement corrosion, and the test methodologies which determine the efficacy of cathodic protection systems favour impressed current technologies. The work completed has investigated the application of traditional and novel corrosion assessment techniques to laboratory samples to assess the protection offered by the hybrid treatment methodology in both treatment phases. In addition, the response of both galvanic and hybrid anodes to environmental conditions has been recorded and assessed before being discussed in the context of steel protection criteria. Finally, an investigation is presented into the on-site deterioration of commercially pure titanium feeder wire installed as part of the hybrid anode system and potential solutions to the problem have been documented. The research undertaken found that the hybrid anode system is capable of protecting steel in challenging, aggressive environments. This was confirmed by steel corrosion rate and indicative steel potential measurements. The responsive behaviour investigation showed that the current output of galvanic and hybrid anodes responds rapidly to changes in the corrosion risk posed to the steel and that this has a direct effect on anode system lifetimes. An assessment of the polarisation-based protection criteria applied to steel in concrete has found that the standard inhibits the use of responsive behaviour, and that revisions which consider the present risk of steel corrosion by considering the corrosion current resulting from the relative aggressivity of the concrete environment would be more valid in their application. A cathodic protection system based on the concepts of pit re-alkalisation and pH maintenance can fully utilise galvanic anode responsive behaviour. It was discovered that the deterioration of commercially pure titanium feeder wire seen on site installations was due to anodising in the presence of chloride media which had the potential to lead to pitting corrosion. The pitting risk varied depending on the duration of the treatment and proximity to the installed anode. An anodically grown oxide delayed the onset of corrosion in aqueous KBr solution, but did not significantly increase the pitting potential.
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Myalo, Zolani. « Graphenised Lithium Iron Phosphate and Lithium Manganese Silicate Hybrid Cathode Systems for Lithium-Ion Batteries ». University of the Western Cape, 2017. http://hdl.handle.net/11394/6036.
Texte intégralRésumé :
Magister Scientiae - MSc (Chemistry)This research was based on the development and characterization of graphenised lithium iron phosphate-lithium manganese silicate (LiFePO4-Li2MnSiO4) hybrid cathode materials for use in Li-ion batteries. Although previous studies have mainly focused on the use of a single cathode material, recent works have shown that a combination of two or more cathode materials provides better performances compared to a single cathode material. The LiFePO4- Li2MnSiO4 hybrid cathode material is composed of LiFePO4 and Li2MnSiO4. The Li2MnSiO4 contributes its high working voltage ranging from 4.1 to 4.4 V and a specific capacity of 330 mA h g-1, which is twice that of the LiFePO4 which, in turn, offers its long cycle life, high rate capacity as well as good electrochemical and thermal stability. The two cathode materials complement each other's properties however they suffer from low electronic conductivities which were suppressed by coating the hybrid material with graphene nanosheets. The synthetic route entailed a separate preparation of the individual pristine cathode materials, using a sol-gel protocol. Then, the graphenised LiFePO4-Li2MnSiO4 and LiFePO4-Li2MnSiO4 hybrid cathodes were obtained in two ways: the hand milling (HM) method where the pristine cathodes were separately prepared and then mixed with graphene using a pestle and mortar, and the in situ sol-gel (SG) approach where the Li2MnSiO4 and graphene were added into the LiFePO4 sol, stirred and calcined together.
2021-04-30
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Söderström, Daniel. « Modelling and Applications of the Hollow Cathode Plasma ». Doctoral thesis, Uppsala universitet, Elektricitetslära, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8747.
Texte intégralRésumé :
This thesis presents experimental and modelling research on atmospheric pressure hollow cathodes and hollow electrodes. Experiments with the hybrid hollow electrode activated discharge (H-HEAD), which is a combination of a hollow cathode and a microwave plasma source, is presented. The experiments show that this source is able to produce long plasma columns in air and nitrogen at atmospheric pressure and at very low gas flow rates. Measurements of the vibrational temperature of the nitrogen molecules are also presented in this thesis. The vibrational temperature is an indication of the electron temperature in the plasma, an important characteristic of the plasma. Modelling work on the hollow cathode at atmospheric pressure with fluid equations is also presented. It is shown that the inclusion of fast and secondary electrons, characteristic of the hollow cathode plasmas, increases the sheath width. The sheath width was found to be of the order of 100 μm. By modelling the plasma as highly collisional by using the drift-diffusion approximation, it was shown that the increase in sheath thickness was larger at lower pressures than at higher pressures. Still, the sheath width can be of the order of 100 μm. A pulsed atmospheric plasma in a hollow electrode geometry was also modelled by the drift-diffusion fluid equations, with the addition of the energy equation for electrons. Rate and transport coefficients for the electrons were calculated from the solution to the Boltzmann equation as functions of mean electron energy. The dynamics of the plasma at pulse rise time showed large electron density and mean energy peaks at the cathode ends, but also that these quantities were enhanced at the centre of the discharge, between the cathode plates.
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Vickers, Simon. « Particle in cell and hybrid simulations of the Z double-post-hole convolute cathode plasma evolution and dynamics ». Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/17874.
Texte intégralRésumé :
The Z-accelerator at Sandia National Laboratories (SNL), is a high-current pulsed power machine used to drive a range of high energy density physics (HEDP) experiments [1]. To achieve peak currents of >20MA, in a rise time of ~100ns, the current is split over four levels of transmission line, before being added in parallel in a double-post-hole convolute (DPHC) and delivered to the load through a single inner magnetically insulated transmission line (MITL). The electric field on the cathode electrode, >107Vm-1, drives the desorption and ionisation of neutral contaminants to form a plasma from which electrons are emitted into the anode-cathode (a-k) gap. The current addition path in the DPHC forms magnetic 'null' regions, across which electrons are lost to the anode, shunting current from the inner MITL and load. In experiment, current losses of >10% have been measured within the convolute; this reduces the power delivered to the load, negatively impacting the load performance, as well as complicating the prediction of the Poynting flux used to drive detailed magneto-hydrodynamic (MHD) simulations [2, 3]. In this thesis we develop 3-dimensional (3D) Particle-in-Cell (PIC) and hybrid fluid-PIC computer models to simulate the plasma evolution in the DPHC and inner MITL. The expected experimental current loss at peak current was matched in simulations where Hydrogen plasma was injected from the cathode elec- trode at a rate of 0.0075mlns-1 (1ml=1015cm-2), with an initial temperature of 3eV. The simulated current loss was driven by plasma penetrating the downstream side of the anode posts, reducing the effective a-k gap spacing and enhancing electron losses to the anode. The current loss at early time (<10MA), was matched in simulations where space-charge-limited (SCL) electron emission was allowed directly from the cathode; to match the loss over the entire current pulse, a delay model is motivated. Here, plasma injection was delayed after the start of SCL emission, based on realistic plasma expansion velocities of ~3cmμs-1. The PIC model, which was necessary to accurately simulate the kinetic behaviour of the lower density plasma and charged particle sheaths, was computationally intensive such that the spatial resolutions achieved in the 3D simulations were relatively poor. With the aim of reducing the computational overhead, allowing finer spatial resolutions to be accessed, we investigate the applicability of hybrid techniques to simulating the cathode plasma in the convolute. Our PIC model was both implemented in the resistive MHD code, Gorgon, where part of the plasma was modelled in the single fluid approximation, and extended to include an inertial two-fluid description of the plasma. The hybrid models were applied to the DPHC simulations, the results from which are used to motivate a three component model; here, the densest part of the convolute plasma is modelled using the single fluid MHD approximation, transitioning to a fully kinetic PIC description of the lower density plasma and charged particle sheaths, linked by a two-fluid description.
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El, jouad Zouhair. « Réalisation et caractérisation des cellules photovoltaïques organiques ». Thesis, Angers, 2016. http://www.theses.fr/2016ANGE0022/document.
Texte intégralRésumé :
Cette thèse s’insère dans un projet d’élaboration et de caractérisation des cellules photovoltaïques organiques classiques et inverses, plus précisément il s’agit d’améliorer les performances des cellules via des couches tampons anodiques et cathodiques originales. Nous avons commencé d’améliorer les couches tampons cathodiques avec différents donneurs d’électrons: phtalocyanine de cuivre CuPc, subphtalocyanine SubPc et dérivés de thiophène organiques. Dans le premier cas de donneur d’électrons (CuPc), nous avons mis en évidence l’effet d’une fine couche d’un composé de césium, utilisée comme couche tampon cathodique dans des cellules inverses, sur la collecte des électrons après un traitement thermique. Nous avons montré aussi que la couche tampon cathodique hybride, Alq3 (9nm) / Ca (3nm) améliore les performances des cellules quelque soit le donneur d’électrons et sans nécessité de recuit. Dans le cas de drivés de thiophène, nous avons montré comment la morphologie de surface des couches organiques peut influencer les performances des cellules photovoltaïques organiques. Et dans le cas de SubPc utilisé dans des cellules inverses, nous avons étudié l’effet de la vitesse de dépôt de la couche SubPc sur sa morphologie. Concernant l’amélioration de la couche tampon anodique, nous avons étudié des cellules classiques à base SubPc et du pentathiophene (5T). Après l’optimisation de l’épaisseur des donneurs d’électrons, nous avons montré que la bicouche MoO3 (3 nm) / Cul (1,5 nm) utilisée comme couche tampon anodique, permet d'améliorer les performances des cellules, quelque soit le donneur d’électrons. Dans le cas du SubPc, nous avons obtenu un rendement qui approche de 5%This thesis concerns elaboration and characterization of classical and inverse organic photovoltaic cells, specifically improving the anodic and cathodic buffer layers. We started by improving the cathode buffer layers with different electron donors: copper phthalocyanine CuPc, subphtalocyanine SubPc and thiophene derivatives (BSTV and BOTV). In the first case of electron donor (CuPc), we highlighted the effect of the thin layer of cesium compound, used as a cathodic buffer layer in inverse cells, on the collection of electrons after heat treatment.We have also shown that the hybrid cathodic buffer layer, Alq3 (9 nm) / Ca (3nm) improves the cell performance whatever the electron donor without annealing. In the case of thiophene derivatives, we have shown how the morphology of the organic layers surface can influence the performance of organic photovoltaic cells. In the case of SubPc used in inverse cells, we studied the effect of the deposition rate of the layer on the morphology of SubPc surface.Regarding the improvement of the anodic buffer layers, we investigated those based on the SubPc and pentathiophene (5T) in classical cells. After optimization of the electron donors thickness, we have shown that the bilayer MoO3 (3 nm) / CuI (1.5 nm) used as an anodic buffer layer, improves cell performances, whatever the electron donor. In the case of SubPc, we obtained a efficiency approaching 5%
Chapitres de livres sur le sujet "Hybrid cathodes"
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Wen, Zhenhai, Suqin Ci et Junhong Chen. « Nanocarbon-Based Hybrids as Cathode Electrocatalysts for Microbial Fuel Cells ». Dans Nanocarbons for Advanced Energy Conversion, 215–32. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2015. http://dx.doi.org/10.1002/9783527680016.ch8.
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Murugesan, Chinnasamy, Baskar Senthilkumar, Kriti Choudhary et Prabeer Barpanda. « Cobalt–Phosphate-Based Insertion Material as a Multifunctional Cathode for Rechargeable Hybrid Sodium–Air Batteries ». Dans Recent Research Trends in Energy Storage Devices, 35–41. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6394-2_5.
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Godefroidt, Emile, Bjorn Van Belleghem et Tim Soetens. « Effectiveness and Throwing Power of Hybrid Anode Cathodic Protection in Chloride Contaminated Reinforced Concrete ». Dans RILEM Bookseries, 175–86. Cham : Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-75507-1_18.
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Goyal, Megha, et Tapas Kumar Mandal. « Influence of Different Precipitating Agents on the Synthesis of NiMn-LDHs Based Cathode Materials for High Performance Hybrid Devices ». Dans Springer Proceedings in Physics, 187–92. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1971-0_28.
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Parbey, Joseph, Fehrs Adu-Gyamfi et Michael Gyan. « Progress in Cathode Materials for Methanol Fuel Cells ». Dans Methanol Fuel - New Developments, Perspectives and Applications [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1003869.
Texte intégralRésumé :
Methanol fuel cells are the most viable alternative to lithium-ion batteries for portable and other applications. The performance of methanol fuel cell depends in part on the microstructure, contact at the electrode-electrolyte interface, and oxygen reduction reactions (ORR) taking place at the cathode, which requires highly efficient cathode materials. The cathode materials have a significant impact on the performance of methanol fuel cells, making their selection and development an important field of research. This review paper provides a comprehensive overview of the progress made in cathode material selection for methanol fuel cells over the past decade. The development of different classes of cathode materials and cathode support is extensively discussed with particular emphasis on structure and electrochemical properties and performance. Also presented are research challenges and opportunities in developing new cathode materials and future trends. Finally, this review paper provides valuable insights into advancements in cathode material selection for methanol fuel cells, sheds light on hybrid composites support materials, and paves the way for further innovation in the pursuit of efficient and commercially viable methanol fuel cell technologies.
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Rajpurohit, Praveen, et Manaswini Behera. « Light-assisted microbial electrochemical technologies for bioelectricity generation and product recovery ». Dans Resource Recovery from Industrial Wastewater through Microbial Electrochemical Technologies, 61–80. IWA Publishing, 2024. http://dx.doi.org/10.2166/9781789063813_0061.
Texte intégralRésumé :
With the increase in demand for the improvement of microbial electrochemical technologies (METs) for bioelectricity generation and product recovery, light-assisted METs have developed as an option. The use of light helps in the electrohydrogenesis process at the cathode. Various variants of light-assisted METs employ photosynthetic bacteria/algae, anode and photocathode assembly, and so on. Microbial fuel cells (MFCs) using photosynthetic bacteria, bioelectrodes, and hybrids of photoelectrocatalytic cells (PECs) and MFCs show superior performance compared to individual MFCs. The dye-sensitized solar cell coupling of MFCs helps enhance electrohydrogenesis and H2 production. This book chapter deals with all types of light-assisted METs. The effect of the configuration, electrode material, electrolyte, and physical and chemical factors on the performance of light-assisted METs is discussed. The miniaturizing and stacking of reactors in solar-assisted METs is a current approach showing superior performance. The value-added products formed at the cathodic compartment, carbon-based or H2 gas, are discussed and reported literature compared with the enhanced recovery of existing METs.
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M. Orona-Hinojos, Jesus. « Innovative Double Cathode Configuration for Hybrid ECM + EDM Blue Arc Drilling ». Dans Drilling Technology. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97547.
Texte intégralRésumé :
Electrical discharge machining is a machining method generally used for machining hard metals, those that would be high cost or have poor performance to machine with other techniques using, e.g., lathes, drills, or conventional machining. Therefore, also known as thermal processes like EDM, Plasma or Laser cutting can be used in drilling operations with poor metallurgical quality on cutting edge and will be necessary complement with other processes such as electrochemical machining (ECM). Both ECM and EDM processes use electrical current under direct-current (DC) voltage to electrically power the material removal rate (MRR) from the workpiece. However in ECM, an electrically conductive liquid or electrolyte is circulated between the electrode(s) and the workpiece for permitting electrochemical dissolution of the workpiece material. While the EDM process, a nonconductive liquid or dielectric is circulated between the cathode and workpiece to permit electrical discharges in the gap there between for removing the workpiece material. Both are principle too different, EC using an electrical conductive and ED using a dielectric medium. But exist a way that can to do a combination of Pulsed EC + ED Simultaneous and allowing the coexist both process, in a semidielectric medium, where both condition exist in the same time, therefore in this hybrid is possible create a tooling device dual cathode for drilling process with promissory advantages fast hole for this innovative hybrid ECDM Simultaneous, this hybrid it’s knew as blue arc drilling technology.
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Arif, Khizra, Abdul Shakoor, Muhammad Awais, Marvi Dashi, Behram Khan Ajat Khel, Bentham Science Publisher Sami Ur Rehman, Khansa Masood, Farah Hussain, Waheed Alam et Muhammad Atif. « Graphene-based Materials for Electrochemical Energy Storage Devices-EESDs ; Opportunities and Future Perspective ». Dans The 2-Dimensional World of Graphene, 160–76. BENTHAM SCIENCE PUBLISHERS, 2024. http://dx.doi.org/10.2174/9789815238938124010011.
Texte intégralRésumé :
The material's exciting properties, which have substantially expanded the field of study, include its enormous surface area, outstanding electrical conductivity, extreme thinness, amazing electron kinesis, and cutting-edge mechanical control. These topographies are largely active for various energy-storage devices (EESDs) such as supercapacitors, hybrid cathode and anode materials, lithium-sulfur batteries, lithiumion batteries, lithium-oxygen batteries, and sodium-ion batteries. The scalability, stability, and uniformity of nanomaterials made of carbon are essential for the development of graphene-based energy storage devices.
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Litovko, Iryna, Alexey Goncharov, Andrew Dobrovolskyi et Iryna Naiko. « The Emerging Field Trends Erosion-Free Electric Hall Thrusters Systems ». Dans Plasma Science and Technology [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99096.
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The Hall-type accelerator with closed Hall current and open (that is unbounded by metal or dielectric) walls was proposed and considered both theoretically and experimentally. The novelty of this accelerator is the use of a virtual parallel surface of the anode and the cathode due to the principle of equipotentialization of magnetic field lines, which allows to avoid sputtering of the cathode surface and preserve the dynamics of accelerated ions. The formation of the actual traction beam should be due to the acceleration of ions with the accumulated positive bulk charge. A two-dimensional hybrid model in cylindrical coordinates is created in the framework of which the possibility of creation a positive space charge at the system axes is shown. It is shown that the ions flow from the hump of electrical potential can lead to the creation of a powerful ion flow, which moves along the symmetry axis in both sides from the center.
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Mohammadi, Arash. « Hybrid nanomaterials of hollow carbon spheres as cathode materials ». Dans Nanostructured Lithium-ion Battery Materials, 87–109. Elsevier, 2025. http://dx.doi.org/10.1016/b978-0-443-13338-1.00024-1.
Texte intégralActes de conférences sur le sujet "Hybrid cathodes"
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Major, K., G. Brisard et J. Veilleux. « Lithium Iron Phosphate Coatings Deposited by Means of Inductively-Coupled Thermal Plasma ». Dans ITSC2015, sous la direction de A. Agarwal, G. Bolelli, A. Concustell, Y. C. Lau, A. McDonald, F. L. Toma, E. Turunen et C. A. Widener. ASM International, 2015. http://dx.doi.org/10.31399/asm.cp.itsc2015p0566.
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Abstract Lithium-ion batteries have high energy efficiency and good cycling life and are considered as one of the best energy storage device for hybrid and/or electrical vehicle. Still, several problems must be solved prior to a broad adoption by the automotive industry: energy density, safety and costs. To enhance both energy density and safety, the current study aims at depositing binder-free cathode materials using inductively-coupled thermal plasma. In a first step, lithium iron phosphate LiFePO4 powders are synthesized in an inductively-coupled thermal plasma reactor and dispersed in a conventional polyvinylidene fluoride (PVDF) binder. Then, binder-free LiFePO4 coatings are directly deposited onto nickel current collectors by solution precursor plasma spraying (SPPS). These plasma-derived cathodes (with and without PVDF binder) are assembled in button cells and tested. Under optimized plasma conditions, cyclic voltammetry shows that the electrochemical reversibility of plasma-derived cathodes is improved over that of conventional sol-gel derived LiFePO4 cathodes. Further results related to the substitution of iron with manganese in the SPPS precursors (LiMPO4, where M = Fe or Mn) are discussed.
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Tucker, David, Larry Lawson, Thomas P. Smith et Comas Haynes. « Evaluation of Cathodic Air Flow Transients in a Hybrid System Using Hardware Simulation ». Dans ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97107.
Texte intégralRésumé :
Effective control of cathode airflow in a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system is critical to thermal management of a fuel cell stack. Hybrid fuel cell turbine designs often incorporate the use of a valved hot air bypass in parallel with the cathode flow to divert a portion of the compressor effluent around the fuel cell system. The primary objective of this valve in the early development of hybrid power systems was to facilitate system startup. From a system controls perspective, the hot air bypass offers the means to balance and manipulate the level of airflow supplied to the fuel cell stack at a minimal efficiency penalty. Manipulation of this valve has a significant impact on stack performance and reliability, as well as cathodic exhaust airflow conditions. Since the turbine is directly coupled to the fuel cell subsystem through the cathode airflow, non-linear effects are propagated through the system components in response to any hot air bypass valve change. The effect of cathode flow transients on hybrid system performance has been evaluated though the manipulation of a hot air bypass valve on a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). A brief overview of this experimental facility is provided and has been described in more detail previously. Open loop experiments were conducted using the facility, where a perturbation was made to the hot air bypass flow and turbine speed was allowed to change in response. The impact of the transients to both fuel cell and turbine performance are discussed.
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Avdeev, Ilya V., et Mehdi Gilaki. « Explicit Dynamic Simulation of Impact in Cylindrical Lithium-Ion Batteries ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88165.
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High-voltage lithium-ion batteries are increasingly used in electric and hybrid-electric vehicles. Due to a risk of being in an accident, these energy storage systems should be analyzed thoroughly so that the risk of failure or serious damage during accidents is minimized. In this research a three-dimensional finite element simulation of a cylindrical battery cell is performed to study the behavior of the cell under various loading conditions. Li-Ion batteries consist of very thin layers of anodes, cathodes and separators that are packed into a cylindrical-spiral shape. This non-homogeneity nature of the battery cells makes the finite element explicit model very complicated. In this study, a homogenized 3-D model of the cell has been developed that is more suitable for explicit high-strain-rate transient analyses. Another model using layered solid or thick shell elements was generated. For the latter, partially two-phased homogenized material properties were used. Three different configurations are considered to analyze the battery packs: an indentation test with a rigid tube, longitudinal crushing between rigid plates, and transverse crushing. Results from these numerical simulations were consistent for models with thick shell elements and homogenized models.
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Lambruschini, Fabio, Mario L. Ferrari, Alberto Traverso et Luca Larosa. « Emergency Shutdown Management in Fuel Cell Gas Turbine Hybrid Systems ». Dans ASME Turbo Expo 2014 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25432.
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A real-time dynamic model representing the pressurized fuel cell gas turbine hybrid system emulator test rig at Thermochemical Power Group (TPG) laboratories of the University of Genoa has been developed to study the fuel cell behavior during different critical operative situations like, for example, load changes (ramp and step), start-up and shut-down and, moreover, to implement an emergency shutdown strategy in order to avoid any damage to the fuel cell and to the whole system: focus has been on cathode/anode differential pressure, which model was validated against experimental data. The real emulator plant (located in Savona University campus) is composed of a 100 kW recuperated micro gas turbine, a modular cathodic vessel (4 modules of 0.8 m3 each) located between recuperator outlet and combustor inlet, and an anodic circuit (1 module of 0.8m3) based on the coupling of a single stage ejector with an anodic vessel. Different simulation tests were carried out to assess the behavior of cathode-anode pressure difference, identifying the best control strategies to minimize the pressure stress on fuel cell stack.
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Hao, Xia, Shenghao Wang, Takeaki Sakurai et Katsuhiro Akimoto. « The effect of cathode buffer in small molecule organic solar cells ». Dans 2nd Asia-Pacific Hybrid and Organic Photovoltaics. Valencia : Fundació Scito, 2017. http://dx.doi.org/10.29363/nanoge.ap-hopv.2018.047.
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Opitz, Andreas, Dominique Lungwitz, Raphael Schlesinger, Sujitkumar Bontapalle, Susy Varughese, Keli Fabiana Seidel, Thomas Krüger, Jan Behrends, Seth R. Marder et Norbert Koch. « Polyethylenimine cathode interlayer : influence of solvent on functionality and single-step formation from polymer blend solution ». Dans Organic, Hybrid, and Perovskite Photovoltaics XXII, sous la direction de Zakya H. Kafafi, Paul A. Lane, Gang Li, Ana Flávia Nogueira et Ellen Moons. SPIE, 2021. http://dx.doi.org/10.1117/12.2593881.
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Banta, Larry E., Bernardo Restrepo, Alex J. Tsai et David Tucker. « Cathode Temperature Management During Hybrid System Startup ». Dans ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33121.
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Management of air flow through the cathode of a hybrid Solid Oxide Fuel Cell/Gas Turbine generation system is of critical importance for the survival of the fragile fuel cell. The cell must be protected from excessive thermal gradients within each cell/stack and from pressure differences between the anode and cathode. While significant modeling of hybrid system performance has been done for the steady state case, only modest attention has been given to startup and shutdown of a hybrid system. Various researchers have performed modeling studies on SOFC during startup, and have concluded that thermal ramp-up times can require anywhere from less than one hour to more than four hours to avoid thermal shock and potential destruction of the fuel cells. For hybrid systems employing single spool turbine/compressor systems, gradual ramping will be difficult because the rotating components must be brought up to full operating speed quickly to avoid stalling the compressor. This paper proposes a strategy for accommodation of the conflicting startup constraints using both experimental data from the NETL HyPer system and simulation approaches.
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Booth, Ronald E., Yuan Xiong, Yuxuan Liu, Yong Zhu, Harald W. Ade et Brendan T. O'Connor. « ITO-free fully solution-processed flexible semi-transparent organic photovoltaics utilizing metal nanowire for anode and cathode ». Dans Organic, Hybrid, and Perovskite Photovoltaics XXI, sous la direction de Kwanghee Lee, Zakya H. Kafafi, Paul A. Lane, Harald W. Ade et Yueh-Lin (Lynn) Loo. SPIE, 2020. http://dx.doi.org/10.1117/12.2570470.
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Chen, Jinwei, Kuanying Gao, Maozong Liang et Huisheng Zhang. « Performance Evaluation of a SOFC-GT Hybrid System With Ejectors for the Anode and Cathode Recirculations ». Dans ASME Turbo Expo 2017 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63745.
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The recirculation of the anode and cathode exhaust has huge benefits on the fuel cell system, for instance, keeping proper operating conditions of the reformer and preheating the inlet air which reduces the recuperator size. Furthermore, the ejectors used for the fuel cell recirculation are more reliable and low-cost in maintenance than high temperature blowers. In this paper, an anode and cathode recirculation scheme, both equipped with ejectors, was designed in a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) hybrid system. Additionally, a blower was added between the compressor and the heat exchanger to overcome the significant pressure loss caused by the cathode ejector. This configuration separates the compressor from the fuel cell and turbine components, introducing more flexibility in system modification. The investigations were conducted to analyze the performance of the hybrid system with anode and cathode ejectors in this paper. Firstly, the ejector model was established based on the energy, mass and momentum balance equations. Furthermore, it was validated that the ejector model was consistent with the reference data. Secondly, the stand-alone performance of the anode and cathode ejectors was analyzed. The geometry parameters of the ejectors were determined based on the design conditions. Then the off-design performance was analyzed based on the designed ejectors geometry. The results show that the performance of the ejectors is greatly influenced by the inlet conditions of the primary and secondary fluid mass flow rate. Finally, the anode and cathode ejectors were integrated into the SOFC-GT hybrid system. Meanwhile, the off-design and dynamic behaviors of the whole SOFC-GT hybrid system with anode and cathode ejectors for recirculation loops were analyzed. In the end, the results show that the designed ejectors can effectively satisfy the demands of the SOFC-GT system with anode and cathode recirculation loops. And the safety range of relative fuel flow rate is from 0.42 to 1.22 when the rotator speed is constant.
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VanOsdol, John G., Randall Gemmen et Edward Parsons. « Using Staged Compression to Increase the System Efficiency of a Coal Based Gas Turbine Fuel Cell Hybrid Power Generation System With Carbon Capture ». Dans ASME 2008 Power Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/power2008-60111.
Texte intégralRésumé :
This paper examines two coal-based hybrid configurations that employ separated anode and cathode streams for the capture and compression of CO2. One system uses a single compressor to compress and partially preheat the cathode air flow. The second system replaces the single compressor with a two stage compression process with an intercooler to extract heat between the stages, and to reduce the work that is required to compress the air flow in the cathode stream. Calculations are presented for both systems with and without heat recuperation. For the single compressor system with heat recuperation the hybrid system assumes the form of a recuperated Brayton cycle; when the recuperator is not present the hybrid system assumes the form of a standard Brayton cycle. The calculation results show that an increase of 2.2% in system efficiency was obtained by staging the compression for these cycles.
Rapports d'organisations sur le sujet "Hybrid cathodes"
1
Lawson et Thompson. L52100 Hot-Spot Protection for Impressed Current Systems. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), septembre 2003. http://dx.doi.org/10.55274/r0010153.
Texte intégralRésumé :
As pipeline coating and associated cathodic protection (CP) systems age, areas along the pipeline inevitably develop that fall below a prescribed CP criterion. In efforts to meet an adequate CP criterion, engineers often resort to supplementing their existing CP system with magnesium anodes at these "low" potential areas resulting in a "hybrid" cathodic protection system consisting of an impressed current CP system (ICCP) supplemented with magnesium (Mg) anodes. This often achieves the desired result i.e. the potential measured over the pipe becomes more negative. However, there remain several unanswered questions concerning the real benefits to the polarization level of the pipe and the overall effect on the impressed current cathodic protection system. The primary objective of this PRCI project was to develop a better understanding of the relationship between ICCP systems and Mg anodes installed as hot-spot protection. This understanding will assist CP engineers in the design and operation of effective, economic CP systems.