Academic literature on the topic 'Vanadium Bromide Redox Flow Cell'
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Journal articles on the topic "Vanadium Bromide Redox Flow Cell"
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Vafiadis, Helen, and Maria Skyllas-Kazacos. "Evaluation of membranes for the novel vanadium bromine redox flow cell." Journal of Membrane Science 279, no. 1-2 (August 1, 2006): 394–402. http://dx.doi.org/10.1016/j.memsci.2005.12.028.
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Skyllas‐Kazacos, M., and F. Grossmith. "Efficient Vanadium Redox Flow Cell." Journal of The Electrochemical Society 134, no. 12 (December 1, 1987): 2950–53. http://dx.doi.org/10.1149/1.2100321.
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Skyllas‐Kazacos, M., M. Rychcik, R. G. Robins, A. G. Fane, and M. A. Green. "New All‐Vanadium Redox Flow Cell." Journal of The Electrochemical Society 133, no. 5 (May 1, 1986): 1057–58. http://dx.doi.org/10.1149/1.2108706.
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Ferrigno, Rosaria, Abraham D. Stroock, Thomas D. Clark, Michael Mayer, and George M. Whitesides. "Membraneless Vanadium Redox Fuel Cell Using Laminar Flow." Journal of the American Chemical Society 124, no. 44 (November 2002): 12930–31. http://dx.doi.org/10.1021/ja020812q.
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Piwek, Justyna, C. R. Dennison, Elzbieta Frackowiak, Hubert Girault, and Alberto Battistel. "Vanadium-oxygen cell for positive electrolyte discharge in dual-circuit vanadium redox flow battery." Journal of Power Sources 439 (November 2019): 227075. http://dx.doi.org/10.1016/j.jpowsour.2019.227075.
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Rui, Xianhong, Moe Ohnmar Oo, Dao Hao Sim, Subash chandrabose Raghu, Qingyu Yan, Tuti Mariana Lim, and Maria Skyllas-Kazacos. "Graphene oxide nanosheets/polymer binders as superior electrocatalytic materials for vanadium bromide redox flow batteries." Electrochimica Acta 85 (December 2012): 175–81. http://dx.doi.org/10.1016/j.electacta.2012.08.119.
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Li, Yifeng, Maria Skyllas-Kazacos, and Jie Bao. "A dynamic plug flow reactor model for a vanadium redox flow battery cell." Journal of Power Sources 311 (April 2016): 57–67. http://dx.doi.org/10.1016/j.jpowsour.2016.02.018.
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Di Blasi, A., O. Di Blasi, N. Briguglio, A. S. Aricò, D. Sebastián, M. J. Lázaro, G. Monforte, and V. Antonucci. "Investigation of several graphite-based electrodes for vanadium redox flow cell." Journal of Power Sources 227 (April 2013): 15–23. http://dx.doi.org/10.1016/j.jpowsour.2012.10.098.
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Ressel, Simon, Armin Laube, Simon Fischer, Antonio Chica, Thomas Flower, and Thorsten Struckmann. "Performance of a vanadium redox flow battery with tubular cell design." Journal of Power Sources 355 (July 2017): 199–205. http://dx.doi.org/10.1016/j.jpowsour.2017.04.066.
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Rui, Xianhong, Aishwarya Parasuraman, Weiling Liu, Dao Hao Sim, Huey Hoon Hng, Qingyu Yan, Tuti Mariana Lim, and Maria Skyllas-Kazacos. "Functionalized single-walled carbon nanotubes with enhanced electrocatalytic activity for Br-/Br3- redox reactions in vanadium bromide redox flow batteries." Carbon 64 (November 2013): 464–71. http://dx.doi.org/10.1016/j.carbon.2013.07.099.
Full textDissertations / Theses on the topic "Vanadium Bromide Redox Flow Cell"
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Poon, Grace Chemical Sciences & Engineering Faculty of Engineering UNSW. "Bromine complexing agents for use in vanadium bromide (V/Br) redox flow cell." Publisher:University of New South Wales. Chemical Sciences & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41210.
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The Vanadium bromide (V/Br) flow cell employs the Br3-/Br- couple in the positive and the V(II)/V(III) couple in the negative half cell. One major issue of this flow cell is bromine gas formation in the positive half cell during charging which results from the low solubility of bromine in aqueous solutions. Bromine complexing agents previously used in the zinc-bromine fuel cell were evaluated for their applicability in V/Br flow cell electrolytes. Three quaternary ammonium bromides: N-ethyl-N-methyl-morpholinium bromide (MEM), N-ethyl-N-methyl-pyrrolidinium bromide (MEP) and Tetra-butyl ammonium bromide (TBA) were studied. It is known that aqueous bromine reacts with quaternary ammonium bromides to form an immiscible organic phase. Depending on the number of quaternary ammonium bromides used and the environmental temperature, the second phase formed will either be solid or liquid. As any solid formation would interrupt the flow cell operation, potential formation of such kind has to be eliminated. Stability tests of simulated V/Br electrolyte with added quaternary ammonium bromides were carried out at 11, 25 and 40 oC. In the absence of bromine, the addition of MEM, MEP and TBA were found to be stable in V/Br electrolytes. However, in the presence of bromine, solid formation was observed in the bromine rich organic phase when the V/Br electrolyte contained a single quaternary ammonium bromide (QBr) compound. For V/Br electrolytes with binary or ternary QBr mixtures containing TBA, the presence of bromine caused a viscous polybromide phase to form at room temperature and the release of bromine gas at higher temperature. Only a binary mixture of MEM and MEP formed a stable liquid organic phase between 11 ?? 40 oC. In this study it was found that V/Br electrolytes containing a binary QBr mixture (0.75M) of MEM and MEP gave the best combination that formed an orange oily layer in the presence of bromine without solidification between 11 ?? 40oC. Furthermore, it was found that samples of V/Br electrolytes containing a ternary QBr mixture, are less effective in bromine capturing if the total QBr concentration was less than 1 M at 40oC, where bromine gas evolution was observed. From electrochemical studies of V3+/V2+, it was found that the addition of MEM and MEP had a minimal effect on the formal potential of the V3+/V2+ couple, the V2+/V3+ transfer coefficient and the diffusion coefficient of V3+. Therefore, MEM and MEP can be added to the negative half-cell of a V/Br flow cell without major interference From linear sweep voltammetry, the kinetics of the Br-/Br3- redox couple was found to be mass transfer controlled. After the addition of MEM and MEP mixture, the exchange current density was found to decrease from 0.013 Acm-2 to 0.01 Acm-2. On the other hand the transfer coefficient before and after MEM and MEP addition was found to be 0.5 and 0.44 respectively. Since the kinetic parameters were not significantly affected by the addition of MEM and MEP mixture, they can be added to the positive half-cell of the V/Br flow cell as bromine complexing agents. The electrochemical studies of both V3+/V2+ and Br-/Br3- showed the addition of MEM and MEP has minimal interference with the redox reactions of the vanadium bromide flow cell. This thesis also investigated the effect of MEM and MEP addition on the cell performance of a lab scale V/Br flow cell using two different membranes (ChiNaf and VF11). Flow cell performance for 2 M V3.7+ + 0.19 M MEM + 0.56 M MEP electrolytes utilising ChiNaf membrane at 10 mAcm-2 produced an energy efficiency of 59%, and this decreased to 43% after 15 cycles. For the static cell utilising VF11 membrane, the addition of MEM and MEP reduced the energy efficiency from 59.7% to 43.4%. It is believed that this is caused by the mass transfer controlled Br-/Br3- couple in the complexed positive half-cell solution. Therefore, uniformity between the organic and aqueous phase is important for flow cells utilising electrolytes with MEM and MEP. Finally, the polarization resistance of a lab scale V/Br flow cell utilising ChiNaf membrane and 2 M V3.7+ electrolytes was found to be slightly higher during cell charging (3.9 cm2) than during the discharge process (3.6 cm2), which is opposed to that in the all-vanadium redox cell.
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Prifti, Helen Chemical Sciences & Engineering Faculty of Engineering UNSW. "Electrolyte and membrane studies of the novel vanadium bromide redox flow cell." Awarded by:University of New South Wales. Chemical Sciences & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41478.
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The novel Vanadium Bromide (V/Br) redox flow cell employs a V (III)/V (II) couple in the negative half-cell and a Br/Br2 couple in the positive half-cell, with hydrobromic acid and hydrochloric acid as the supporting electrolyte. This study evaluated the chemical and electrochemical properties of the electrolytes and assessed experimental and commercial membranes for use in the V/Br flow cell. A number of techniques were employed to characterise the composition of the V/Br flow cell electrolytes. During charge, the conductivity of the positive half-cell electrolyte increased, whilst the density and viscosity increased. The reverse was observed for the negative half-cell. The UV-visible spectra of the electrolytes showed characteristic peak wavelengths of the vanadium oxidation states and provided and insight into the halogenated species forming during the operation of the V/Br flow cell. The electrochemical properties of the electrolytes were also examined using cyclic voltammetry. NMR studies examined the relationships between the 35CI and 79Br nuclei in the presence of halide and paramagnetic vanadium ions. It was established that the SOC and performance of the V/Br flow cell can be measured by changes in slllectral chemical shifts and line widths. Small-scale cycling experiments were conducted to evaluate the performance of ion exchange membranes in the V/Br redox flow cell. Of the membranes evaluated, a number were not suitable for use due to high membrane resistances or low chemical stability. The perfluorinated Nafion?? and Gore Select?? ion exchange membranes proved to be the most chemically inert and showed low resistances. The Gore Select?? membranes did however exhibit blistering during extended cycling. The chemical stability and cycling performance of the HiporeTM microporous separator showed promise for future studies to optimise the selectivity and ion exchange capacity of the membrane. Tests of membrane ion exchange capacity, diffusivity and conductivity mirrored the properties displayed in the cell cycling experiments. Results suggested that the structural characteristics of the membrane (including functionality and crosslinking) greatly influenced membrane properties and performance. Tests of long term stability showed a negative change in membrane properties. These changes did not however reflect measured changes during cell cycling experiments.
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Sapouna, Ioanna. "Development of cellulose-based membranes for Vanadium Redox Flow Cell Battery applications." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-235217.
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In this study, the development of a cellulose-based membrane for use in Vanadium Redox Flow Cell Batteries (VRFBs) was investigated. Cellulose is the most abundant biopolymer on earth and due to its versatility it finds multiple applications. However, cellulose and its derivatives can be easily hydrolyzed in the amorphous regions, under acidic conditions. In order to bypass this problem and use this tough material in the highly acidic and oxidative environment of a VRFB, two approaches were utilized. First, cellulose nanocrystals (CNCs) were employed, which basically lack amorphous regions, to minimize the effect of hydrolysis. An additional advantage is that CNCs can create films with specific stereochemistry, as they pack closely, in helical structures. Second, the surface of the CNCs was modified with the use of trichloro(1H,1H,2H,2H- perfluorooctyl)silane (TCPOS). This molecule has a long fluorocarbon chain, which acts protectively towards hydrolysis of the CNCs. The choice of silane was made in order to produce a material that can resemble Nafion, the most popular copolymer used in VRFBs. Nafion has a fluorocarbon, Teflon-like, backbone and a hydrophilic side chain that consists of a sulfonic acid groups. The first step was to make a material that is stable under the VRFB conditions. The membranes were characterized with AFM imaging, FTIR spectroscopy, contact angle measurements, and tensile testing. With the use of the product of alkoxylation of TCPOS (TMPOS), hydrophobic membranes were produced that exhibit contact angle with water larger than that of Nafion. Young’s modulus of the membranes with TMPOS was larger compared to the one of CNC membranes without TMPOS. To determine stability against acidic conditions, Dynamic Light Scattering (DLS) was used. Additionally, stability of the membranes after acid and Vanadium solution treatment was performed with gravimetric measurements. From the results, 67% of the samples tested remained intact under high ionic strength and acidic conditions. In addition, the effect of the amount of silane on the membranes was evaluated. The results of this study are promising and encourages further research on this direction.I denna studie undersöktes utvecklingen av ett cellulosabaserat membran för användning i Vanadin redoxflödesbatterier (VRFB, en.). Cellulosa är den mest förekommande biopolymeren på jorden och med dess mångsidighet finns många tillämpningar. Cellulosa, och dess derivat, kan dessvärre enkelt hydrolyseras i amorfa regioner under sura förhållanden. För att kringgå detta problem och för att kunna använda materialet i den sura och oxidativa miljö som förekommer i ett VRFB, användes två tillvägagångssätt. Först användes cellulosananokristaller (CNC, en.) för att minimera effekten av hydrolys, då de huvudsakligen saknar amorfa regioner. Ytterligare en fördel är att man med CNC kan skapa filmer med specifik stereokemi, då de packas tätt i spiralformade strukturer. Det andra tillvägagångssättet var att modifiera CNC-ytan med hjälp av trikloro(1H,1H,2H,2H-perfluoroktyl)silan (TCPOS, en.). Denna molekyl har en lång fluorvätekedja, som skyddar mot hydrolys av CNC. Silan valdes för att skapa ett material som liknar Nafion, som är den vanligaste co-polymeren i VRFB. Nafion har en huvudkedja av fluorväte, liknande Teflon, och en hydrofil sidokedja bestående av sulfonsyragrupper. Det första steget var att göra ett material som är stabilt under de förhållanden som råder i ett VRFB. Membranen karaktäriserades med hjälp av AFM, FTIR-spektroskopi, kontaktvinkelmätningar och dragprov. Alkoxyleringsprodukten som erhölls ifrån TCPOS- behandlingen användes för att tillverka hydrofoba membran med en kontaktvinkel mot vatten som är större än för Nafion. Youngs modul för membran med TMPOS var större än för CNC- membran utan TMPOS. För att klarlägga stabiliteten under sura förhållanden ändvändes DLS. Dessutom testades membranens stabilitet efter syra- och vanadinlösningsbehandling genom olika gravimetriska mätningar. Resultaten visade att 67 % av de testade proverna förblev intakta under förhållanden med hög jonstyrka och surhet. Effekten av mängden använt silan i membranen utvärderades också. Resultaten från denna studie är lovande och uppmuntrar till vidare forskning i denna riktning.
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Hassan, Ali. "Traitement thermochimique et caractérisation spectro-électrochimique des électrodes en feutre de carbone, utilisées dans des cellules pilote d'une batterie à circulation tout vanadium." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30144.
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La demande croissante d'énergie au niveau mondial fait que les énergies obtenues de ressources renouvelables connaissent un essor important, notamment dans la production globale d'électricité propre (ne générant pas des gaz à effet de serre, tels les combustibles fossiles enrichis en carbone). La nature 'intermittente' de ces ressources renouvelables d'énergie implique l'utilisation des dispositifs de stockage de grande échelle, efficaces et économiquement compétitifs. Les batteries à circulation, tout vanadium (VRFB) sont des dispositifs de stockage prometteurs pour les applications stationnaires. En effet, l'absence de contamination irréversible de l'électrolyte est l'avantage principal de cette batterie dont le nombre de cycles 'charge-décharge' est théoriquement illimité. Le graphite et le feutre de graphite sont des matériaux d'électrodes à faible coût utilisés par les VRFB ; cependant le système V(V)/V(IV) (électrode positive) est cinétiquement lent sur ce matériau et introduit une surtension diminuant la tension délivrée par la batterie. Différentes méthodes (chimiques, thermiques, électrochimiques,...) ont été conçues lors de cette thèse pour activer la surface du graphite commercial, càd. améliorer son activité électrocatalytique vis-à-vis de la réaction (VO2 + ⇌VO2+) ayant lieu à l'électrode positive. Cette amélioration a été caractérisée par voltammétrie linéaire (état quasi-stationnaire) et cyclique (état transitoire). En outre, la morphologie de l'électrode et son état de surface ont été analysés par infrarouge à transformée de Fourier (FTIR) et par microscopie électronique à balayage (SEM). De plus, l'interaction électrode-électrolyte a été quantifiée par des mesures d'angle de contact qui ont permis de déterminer l'énergie libre de surface. L'activation de l'électrode a généré différents groupes oxygénés (C-OH, C = O, COOH) sur sa surface, laquelle a par ailleurs augmenté du fait d'une certaine érosion et donc la création d'une rugosité ; ceci s'est traduit par : i) l'augmentation de 35% de l'amplitude du courant du pic obtenu par voltamétrie cyclique (pour le système VO2+/VO2+) et ii) le rapprochement des pics anodique et cathodique (ΔEpics= 300 mV). Les calculs de la théorie fonctionnelle de la densité (DFT) ont été effectués pour évaluer le rôle de ces groupes oxygénés sur la réactivité du système redox VO2+/VO2+(à l'électrode positive). DFT montre que ces groupes d'oxygéne augmente l'hybridation sp3 dans la structure du graphite, ce qui facilite les réactions redox. La constante de transfert électronique hétérogène intrinsèque (k °) de ce même système redox a augmentée de 2,6 et 6,1 fois pour l'oxydation (V(IV)→V(V)) et la réduction (V(V)→V(IV)), respectivement. Par ailleurs l'augmentation constatée de l'énergie libre de surface du feutre de graphite (de 13,9 mN / m à 53,29 mN / m) traduit l'amélioration, par le traitement, des interactions électrode-électrolyte. La performance de l'électrode a été évaluée dans une demi-cellule classique par des cycles de charge/décharge et les résultats ont montré que la tension aux bornes durant la charge diminue (de 1,18 V à 1,04 V) alors que celle obtenue en décharge augmente (de 0,42 V à 0,75 V), après l'activation de GF. Des cycles charge/décharge ont également été réalisés avec un réacteur électrochimique filtre presse (pile et électrolyseur pour VRFB), ayant une surface géométrique de 100 cm2 de GF dans chaque compartiment électrolytique. Grace au traitement effectué, le rendement énergétique et la tension aux bornes se sont améliorés de 20% et 13% respectivement, dans le cas d'une électrolyse en mode galvanostatique (50 A.m2), ce qui montre que les méthodes d'activation proposées sont efficaces et en outre faciles à mettre en œuvreIncrease of the share of renewable energy in the overall power production can ensure the future energy demand and help to cope with the environmental challenges inherent to the carbon enrich fossil fuels. Due to intermittent nature of these renewable resources, cost competitive and efficient energy storage devices are required. Vanadium redox flow batteries (VRFBs) are promising storage devices for the stationary applications due to its easy scalability, long charge-discharge cycles. The graphite and the graphite felt are low cost electrodes materials used by VRFBs which exhibits low kinetic reversibility of the redox reaction involving the system V(V)/V(IV) in the positive half-cell; this fact is responsible of significant kinetics overpotential decreasing the delivered voltage from the battery. In this work, different methods (chemical, thermal, electrochemical,) were tried to activate the surface of commercial graphite, expecting to enhance its electro-kinetics activity, specifically for the positive half-cell reaction (VO2+⇌VO2+). The enhancement of the electro kinetic activity of the electrode surface was characterized by the cyclic and linear sweep voltammetries. Besides the surface chemistry and morphology were analysed by the Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). In another study, the electrode-electrolyte interaction was quantified by contact angle measurements allowing access to the surface free energy determination. The activation method enables to create different oxygenal groups (C-OH, C=O -COOH) on the graphite surface and to increase the surface area. Both effects lead to i) the increase by 35 % of the current magnitude of the peak obtained by cyclic voltammetry (for the system VO2+/VO2+) and ii) the decrease of the ΔEpeaks of the same system by 300 mV. The density functional theory calculations (DFT) were performed to evaluate the individual catalytic role of the these oxygenal groups against the redox couple VO2+/VO2+(in the positive electrode). DFT shows that these oxygenal groups increase sp3 hybridization in the structure of the felt, that are facilitating the redox reactions. The intrinsic heterogeneous electronic transfer constant (k°) of V(V)/V(IV) system is enhanced by 2.6 and 6.1 times for the oxidation (V(IV)→V(V)) and reduction (V(V)→V(IV)) reactions, respectively. The electrode-electrolyte interaction improves because of the increment of the surface free energy of GF from 13.9 mN/m to 53.29 mN/m. The electrode performance was evaluated in the classical half-cell by charge discharge cycles. The charging voltage decrease from 1.18V to 1.04V and the discharge voltage increase from 0.42V to 0.75V, after the activation of GF. Proposed activation methods are novel, easy and effective. The charge discharge cycles of VRFB were performed at stack level, into the electrochemical plug flow reactor, by using 100 cm2 GF in each electrolytic section. At a current density of 50 A.m-2, there is an improvement of 20 % and 13 % in energy and voltage efficiency (VE) of stack respectively, due to treated electrode
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Ressel, Simon Philipp. "Tubular All Vanadium and Vanadium/Air Redox Flow Cells." Doctoral thesis, 2019. http://hdl.handle.net/10251/131203.
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[ES] Un aumento de la generación de energía a partir de fuentes renovables (solar, eólica)
requiere una alta flexibilidad de las redes eléctricas. En este sentido, las baterías de
flujo redox de vanadio (BFRV) han demostrado una excelente capacidad para proporcionar
dicha flexibilidad, mediante el almacenamiento eficiente de energía eléctrica
en el rango de los kWh a los MWh. Sin embargo, sus elevados costes son en la actualidad
unos de los mayores inconvenientes que dificultan una amplia penetración
en el mercado.
En la presente Tesis Doctoral se presenta el desarrollo y evaluación de una celda
tubular especialmente diseñada con una membrana de 5.0mm. Las células tubulares
así diseñadas deberían alcanzar una mayor densidad de potencia (kWm^(-3)). Del
mismo modo, la sustitución de uno de los electrodos por un electrodo bifuncional de
aire debería de incrementar la energía específica de dicha celda (Whkg^(-1)) y reducir,
por tanto, los costes energéticos asociados (€/kWh).
El diseño de la celda desarrollado en la presente Tesis Doctoral facilita la fabricación
de los colectores y membranas actuales con el empleo de procesos de extrusión y
marca un paso importante hacia la fabricación rentable de semiceldas y celdas completas
en el futuro.
Para evaluar el comportamiento de la nueva celda diseñada se han llevado a cabo
estudios de polarización, de espectroscopia de impedancia, y medidas de ciclos de
carga/descarga. Las celdas desarrolladas presentan una corriente de descarga máxima
de 89.7mAcm^(-2) y una densidad de potencia de 179.2kW/m^3. Además, los bajos
sobrepotenciales residuales obtenidos en los electrodos de la celda resultan prometedores.
No obstante, la resistencia del área específica de celda de 3.2 ohm*cm² impone
limitaciones significativas en la densidad de corriente.
Eficiencias Coulomb del 95 % han sido obtenidas, comparables a los valores alcanzados
en celdas planas de referencia. Sin embargo, las pérdidas óhmicas resultan
elevadas, reduciendo la eficiencia energética del sistema al 56 %.
Las celdas tubulares fabricadas con un electrodo de difusión de gas de una sola capa
con Pt/IrO2 como catalizador permiten alcanzar densidades de corriente máximas
de 32mAcm^(-2) (Ecell =2.1 V/0.56V Ch/Dch). Los elevados sobrepotenciales de activación
y el reducido voltaje en circuito abierto (debido a potenciales mixtos) conducen
a una densidad de potencia comparativamente baja de 15.4mW/ cm². El paso de
iones de vanadio a través de la membrana se considera uno de los grandes inconvenientes
en este tipo de celdas tubulares, lo que lleva a que la densidad de energía
real de 23.2Wh l^(-1) caiga por debajo del valor nominal de 63.9Wh l^(-1).[CAT] Un augment de la generació d'energia a partir de fonts renovables (solar, eòlica) requereix una alta flexibilitat de les xarxes elèctriques. En aquest sentit, les bateries de flux redox de vanadi (VRFB) han demostrat una excel·lent capacitat per a proporcionar aquesta flexibilitat, mitjançant l'emmagatzematge eficient d'energia elèctrica en el rang dels kWh als MWh. En la present Tesi Doctoral es presenta el desenvolupament i avaluació d'una cel·la tubular especialment dissenyada amb una membrana de 5.0mm. Les cèl·lules tubulars així dissenyades haurien assolir una major densitat de potència (kWm^(-3)). De la mateixa manera, la substitució d'un dels elèctrodes per un elèctrode bifuncional d'aire hauria d'incrementar l'energia específica d'aquesta cel·la (Whkg^(-1)) i reduir, per tant, els costos energètics associats (€/kWh). El disseny de la cel·la desenvolupat en la present tesi doctoral facilita la fabricació dels col·lectors i membranes actuals amb l'ocupació de processos d'extrusió i marca un pas important cap a la fabricació rendible de semiceldas i cel·les completes en el futur. Per avaluar el comportament de la nova cel·la dissenyada s'han dut a terme estudis de polarització, d'espectroscòpia d'impedància, i mesures de cicles de càrrega/ descàrrega. Les cel·les desenvolupades presenten un corrent de descàrrega màxima de 89.7mAcm^(-2) i una densitat de potència de 179.2kW/m^3. A més, els baixos sobrepotencials residuals obtinguts en els elèctrodes de la cel·la resulten prometedors. No obstant això, la resistència de l'àrea específica de cel·la de 3.2 ohm*cm² imposa limitacions significatives en la densitat de corrent. Eficiències Coulomb del 95 % han estat obtingudes, comparables als valors assolits en cel·les planes de referència. No obstant això, les pèrdues òhmiques resulten elevades, reduint l'eficiència energètica del sistema al 56 %. Les cel·les tubulars fabricades amb un elèctrode de difusió de gas d'una sola capa amb Pt/IrO2 com a catalitzador permeten assolir densitats de corrent màximes de 32mAcm^(-2) (Ecell =2.1 V/0.56V Ch/Dch). Els elevats sobrepotencials d'activació i el reduït voltatge en circuit obert (a causa de potencials mixtes) condueixen a una densitat de potència comparativament baixa de 15.4mW/ cm². El pas de ions de vanadi a través de la membrana es considera un dels grans inconvenients en aquest tipus de cel·les tubulars, el que porta al fet que la densitat d'energia real de23.2Wh l^(-1) caigui per sota del valor nominal de 63.9Wh l^(-1).
[EN] An increase of the power generation from volatile renewable sources (solar, wind) requires a high flexibility in power grids. All Vanadium Redox Flow Batteries (VRFBs) have demonstrated their ability to provide flexibility by storing electrical energy on a kWh to MWh scale. High power and energy specific costs do, however prevent a wide market penetration. In this dissertation a tubular cell design with a membrane diameter of 5.0mm is developed and evaluated. Tubular VRFB cells shall lead to an enhanced power den- sity (kWm^(-3)). Replacement of an electrode with a bifunctional air electrode (Vanadium/ Air Redox Flow Battery) shall allow to increase the specific energy (Whkg^(-1)) and reduce energy specific costs (€/kWh). The developed design facilitates a fabrication of the current collectors and membrane by an extrusion process and marks an important step towards the cost-efficient ex- trusion of entire half cells and cells in the future. To evaluate the cell performance and investigate loss mechanisms, polarization curve, electrochemical impedance spectroscopy and charge/discharge cycling measurements are conducted. Tubular VRFB cells with flow-by electrodes reveal a maximum dis- charge current and power density of 89.7mAcm^(-2) and 179.2kW/m^3, respectively. Low residual overpotentials at the cell's electrodes are encouraging, but the area spe- cific cell resistance of 3.2 ohm*cm² imposes limitations on the current density. Coulomb efficiencies of 95% are comparable to values of planar reference cells, but high ohmic losses reduce the system energy efficiency to 56 %. Tubular VARFB cells with a mono-layered gas diffusion electrode and a Pt/IrO2 catalyst allow for a maximum current density of 32mAcm^(-2) (Ecell =2.1 V/0.56V Ch/Dch). High activation overpotentials and a reduced open-circuit voltage (due to mixed potentials) lead to a comparably low power density of 15.4mW/ cm². Cross- over of vanadium ions through the membrane are considered as a major drawback for tubular VARFB cells and the actual energy density of 23.2Wh l^(-1) falls below the nominal value of Wh l^(-1).
Financial support of my research activities was provided by the BMBF through the common research project tubulAir±.
Ressel, SP. (2019). Tubular All Vanadium and Vanadium/Air Redox Flow Cells [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/131203
TESIS
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Lee, Chia-Hao, and 李佳豪. "Electrochemical study of the Graphite/Glassy Carbon composite electrodes in all-vanadium redox flow cell." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/20607348515327716914.
Full textAbstract:
碩士輔仁大學
化學系
96
Vanadium redox flow cell is very powerful in large-scale energy storage, because it presents high capacity, excellent cycle life, fast response, and large open circuit voltage, etc. Although the overall cell performance depends on several factors, the fundamental knowledge of negative and positive electrode reactions are still importance to be optimized the electrolytes. In this study, we use graphite/glassy carbon as composite electrode of vanadium redox flow cell, and vanadium ion solution were prepared in 1.0M~4.0M H2SO4 as electrolyte. We determined the potential windows of graphite and glassy carbon electrode from voltammograms and Tafel plots. The V(IV)/V(V) and V(II)/V(III) redox reactions in various concentration of sulfuric acid solution had been investigated by cyclic voltammetry and A.C. impedance to study the kinetics between vanadium ion and electrode. Otherwise, we also used spectroelectrochemical method (In-situ UV-Vis. and Ex-situ Raman) to discuss the mechanism of V(IV)/V(V) and V(II)/V(III) redox reactions. The mechanisms were indicated that performances of positive and negative electrodes are corresponded to the concentration of proton, so that we can prepare the concentration of sulfuric acid and vanadium both in 2.0M as the electrolyte of test cell. Three types graphite/glassy carbon composite electrodes were used to test by single cell. And the results indicate that graphite/glassy carbon composite electrodes can promote the efficiency of test cell and total efficiency is from 30%~40% up to 50%~60%.
Book chapters on the topic "Vanadium Bromide Redox Flow Cell"
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"Physical Properties of Negative Half-Cell Electrolytes in the Vanadium Redox Flow Battery." In Electrochemically Enabled Sustainability, 408–41. CRC Press, 2014. http://dx.doi.org/10.1201/b17062-14.
Full textConference papers on the topic "Vanadium Bromide Redox Flow Cell"
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Islam, Rabiul, Benjamin Eckerson, Cameron Nolen, Kwangkook Jeong, and Roy McCann. "Experimental Study on Test-Bed Vanadium Redox Flow Battery." In ASME 2015 9th International Conference on Energy Sustainability collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/es2015-49493.
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An experimental study has been conducted to develop a test-bed for advanced vanadium redox flow battery (VRFB) for renewable energy applications. Lab scale experimental setup has been designed based on enhanced geometry of mechanical components and reduced power consumption in terms of fluid mechanics and thermodynamics. Two tests have been conducted with variations of flowrate, concentration of electrolytes and electrical input power. The VRFB project has been collaborated between Arkansas State University Jonesboro (ASUJ) and University of Arkansas Fayetteville (UAF) to integrate VRFB with micro-grid at UAF. To obtain comparable experimental data, a test bed made of two half cells was constructed and joined together by a permeable membrane designed to facilitate ion transfer between two separate vanadium electrolytes. This research aims to better understand and demonstrate the transient characteristics of VRFB in order to refine the system in hopes of improving efficiency. This paper will focus on the steps taken to experimentally validate preliminary performance of the VRFB test bed. An analytical model has been performed to validate design and test of VRFB. Future work will be addressed to develop a pilot-scale multiple cell stacks with enhanced efficiency and temperature limits.
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Nizam, N. M., M. H. Zulkhifli, A. C. Khor, M. R. Mohamed, and M. H. Sulaiman. "Design and Development of Vanadium Redox Flow Battery (V-RFB) Cell Stack." In 4th IET Clean Energy and Technology Conference (CEAT 2016). Institution of Engineering and Technology, 2016. http://dx.doi.org/10.1049/cp.2016.1286.
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Khabbazi, Ali Ebrahimi, and Mina Hoorfar. "Modeling of Microfluidic Fuel Cells With Flow-Through Porous Electrodes." In ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33220.
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This paper presents a modeling of a microfluidic fuel cell with flow-through porous electrodes using vanadium redox couples as the fuel and oxidant. There are advantages associated with the use of vanadium redox species in microfluidic fuel cell: 1) vanadium redox couples have the possibility of producing high open-circuit potential (up to 1.7 V at uniform PH [1]); 2) they have high solubility (up to 5.4 M) which causes more species available to the electrodes; 3) they do not require metal catalyst for electrochemical reactions so the reactions take place on the bare carbon electrodes. This characteristic of the vanadium redox couple make them a great candidate as reactants as they do not need expensive catalyst coatings on the electrodes. The fuel and the oxidant can be brought into contact with the electrode in two different ways: flowing over the electrodes or flowing through the electrodes. In the presented fuel cell design, the vanadium redox species are forced to flow through the porous electrodes. They finally come to meet each other in the middle microchannel and establish a side-by-side co-laminar flow traveling down the channel. In this paper, the effect of the inlet velocity and electrode porosity has been investigated. As it is expected, the higher velocity results in the higher power densities. For the porosity, however, there is an optimum value. In essence, there is a trade-off between the available electrode surface area and electric conductivity of the solid phase (i.e., the porous carbon electrode). The modeling shows that a porous electrode with a 67% porosity results in the highest power output.
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Wang, Yun, and Sung Chan Cho. "Advanced Modeling of the Dynamics of Vanadium Redox Flow Batteries." In ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2015 Power Conference, the ASME 2015 9th International Conference on Energy Sustainability, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/fuelcell2015-49408.
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In this paper, a multi-dimensional dynamic model of vanadium Redox Flow Batteries (RFB) is employed to predict battery performance and internal operating condition during charge and discharge. The model consists of a set of partial differential equations of mass, momentum, species, charges, and energy conservation, in conjunction with the electrode’s electrochemical reaction kinetics. After validated against experimental data for a vanadium RFB, flow field, temperature distribution, and reactant evolution are presented. The developed numerical tool is extremely useful in optimizing RFB design and control.
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Sujali, S., M. R. Mohamed, S. A. Mad Don, and N. Yusoff. "Method approaches to prevent leakage cell stack of vanadium redox flow battery (VRFB)." In 4th IET Clean Energy and Technology Conference (CEAT 2016). Institution of Engineering and Technology, 2016. http://dx.doi.org/10.1049/cp.2016.1289.
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Sathisha, H. M., and Amaresh Dalal. "Simplified Mathematical Model to Evaluate the Performance of the All-Vanadium Redox Flow Battery." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17366.
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All-vanadium redox flow battery is one of the promising rechargeable battery since it is able to withstand average loads, high energy efficiency and high power output. The battery exhibits the excellent transient behaviour and sustains sudden voltage drop. The dynamics of the battery is governed by the conservation equations of mass and charge. The simplified mathematical model includes major resistances, electrochemical reactions and recirculation of electrolyte through reservoirs. The mathematical model is able to predict the performance of the battery. The cell performance can be increased by increasing the concentration of the vanadium ions, the flow rate and the temperature inside the cell. The model results are validated with the available experimental result which shows better agreement.
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Islam, Rabiul, and Kwangkook Jeong. "Experimental Study on Effects of Operational Parameters on a Single-Cell Test-Bed Vanadium Redox Flow Battery." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10998.
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Abstract This paper describes the experimental characterization of a laboratory scale single-cell vanadium redox flow battery (VRFB) with variations of operational parameters. The single cell was experimentally investigated with respect to energy storage capacity, charge-discharge time, voltage, coulombic and energy efficiencies under various operating parameters such as current densities, electrolyte flow rates, and the ratio of electrolyte volume in electrolyte storage tank and cell. It was found that the voltage efficiency was increased by 11% entailing energy efficiency improvement from 60 to 66% as the electrolyte flowrate was increased from 40 to 220 ml/min. The highest columbic efficiency was achieved at 96% for the current density of 40 mA/cm2 which was 14% higher than that of the current density of 15 mA/cm2. Energy storage capacity was linearly increased with higher ratio of tank to cell volume due to the larger number of vanadium ions present. The improvement in energy storage capacities was observed to be 60, and 41% as the ratio was raised by 67, and 40%, respectively.
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Islam, Rabiul, Cameron Nolen, and Kwangkook Jeong. "Effects of Sulfuric Acid Concentration on Volume Transfer Across Ion-Exchange Membrane in a Single-Cell Vanadium Redox Flow Battery." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72359.
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The vanadium redox flow battery (VRFB) is one of the technologies to be used for storing large-scale renewable energy. The objective of this research is to electrochemically synthesize the V(III) electrolytes with combinations of 2 M VOSO4 and 2–6 M H2SO4, and to investigate the effects of concentration of H2SO4 on vanadium and water transfer across membrane. Transfer of water and vanadium across the membrane was reduced from 19.6 to 6.2 % as the concentration of H2SO4 in the electrolyte increased from 2 to 6 M. Change in volume transferred across the membrane decreased with each successive charge and discharge cycle, and resulted in a reduction in volume transfer from 16.7 % after the first cycle to 2.9 % after the fourth cycle. Energy storage capacity was increased by 50 % by changing the H2SO4 concentration from 2 to 6 M.
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Listenbee, Ryan, Kwangkook Jeong, and Roy McCann. "Integrated Computational and Experimental Framework on Advanced Flow Battery for Renewable Power Plant Applications." In ASME 2014 8th International Conference on Energy Sustainability collocated with the ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/es2014-6501.
Full textAbstract:
A study has been conducted to develop advanced vanadium redox flow battery (VRFB) for renewable energy storage applications using integrated computational and experimental framework. Analytical modeling has been performed to predict electrical outputs based on combined approach including fluid mechanics, electrochemistry, and electric circuit. A lab-scale experimental setup has been designed and built to validate the modeling results. The VRFB project has been collaborated between Arkansas State University Jonesboro and University of Arkansas Fayetteville to focus on pin pointing the transient characteristics of the vanadium redox flow battery in terms of chemical reaction, fluid flow, and electric circuit by obtaining exact solutions from the associated governing differential equations using a numerical approach. To obtain comparable experimental data, a test bed made of two half cells is constructed and joined together by a permeable membrane designed to facilitate ion transfer between two separate vanadium electrolytes, and then the system will be scaled up to multiple cell stacks. This research aims to better understand the transient characteristics of the VRFB in order to refine the system in hopes of improving efficiency. In turn alternative energy such as multi megawatt wind and solar farms should gain more support as the ability to store energy becomes more reliable and economically feasible. This paper will focus on the steps taken to validate the supporting mathematical models, and the preliminary results of the tests conducted using the VRFB test bed. Future work will be addressed to develop a pilot-scale VRFB with enhanced efficiency and temperature limits.
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Siddiquee, Abu Nayem Md Asraf, and Kwangkook Jeong. "Conjugated Dynamic Modeling on Vanadium Redox Flow Battery With Non-Constant Variance for Renewable Power Plant Applications." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67462.
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A parametric modeling study has been carried out to investigate the effect of change in operating conditions on VRFB performance. The objective of this research is to develop a computer program to predict the dynamic behavior of single cell VRFB combining fluid mechanics, reaction kinetics, and electric circuit. This paper deals with the exact solutions obtained by solving the governing differential equations of VRFB by using Maple 2015. Calculations were made under electrolyte concentrations of 1M–3M of V2+, charging-discharging current of 1.85A–3.85A, and tank to cell ratio of 5:1 to 10:1. Results show that the discharging time increases from 2.2 hours to 6.7 hours when the value of electrolytes concentration of V2+ increases from 1M to 3M. However, the charging time decreases from 6.9 hours to 3.3 hours with the increment of applied current from 1.85A to 3.85A. Additionally, when the tank to cell ratio is increased from 5:1 to 10:1, the charging-discharging time increased from 4.5 hours to 8.2 hours. Ampere-hour capacity of the cell was found to increase when molar concentration of vanadium and, tank to cell ratio were increased.