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In an effort to reduce global emissions by electrifying vehicles and machines with internal combustion engines has led to the development of batteries that are more powerful and efficient than the common lead acid battery.  One of the most popular batteries being used for such an installation is lithium ion, but due to its short effective usable lifetime, charging time, and costs has driven researcher to other technologies to replace it.  Vanadium redox flow batteries have come into the spotlight recently as a means of replacing rechargeable batteries in electric vehicles and has previously be used mainly to store energy for load leveling.  It possesses many qualities that would be beneficial to electrify vehicles.  The battery has the ability for power and energy to be sized independently which is not dissimilar to internal combustion vehicles.  It also has the potential for a tolerance to low discharges, fast response time, and can quickly be refueled by replacing the electrolyte; just like is done when a car refuels at the gas station.  The purpose of the study is to determine the possibility of using vanadium redox flow batteries to power heavy construction equipment, a wheel loader, with a finite amount of space available for implementation.  A model has been designed in MATLAB to determine how long the battery could last under typically applications for the wheel loader which needs a peak power of 200 kW.  From the volume available it has been determined that the battery can be installed with an energy capacity of 148 kWh.  The results of the model show that vanadium redox flow batteries can be used to power a wheel loader but due to the limiting energy density and cell components it remains to be impractical.

As society strives to transition for sustainable energy generation is it a major challenge to optimize and develop the renewable energy generation that currently exists, both in terms of individual components and their interactions in the entire energy system. The generation from renewable sources is often irregular and not always when the demand arises. By being able to store the excess energy generated and then deliver it when the demand occur results in a more sustainable energy system. Flow batteries are a possible technology for energy storage. An important component of flow batteries are vanadium and to find methods for extracting vanadium in an economical way is an important step in the development of this technology. The idea behind the thesis was therefore to investigate different extraction methods for vanadium where the most promising methods, from an economic and energy perspective, are examined in more detail. The vanadium should then be used to electrolyte in flow batteries. It has also been examined how the cost is affected by moving a planned facility for extraction from the ashes to a developing country with lower personnel costs. In the thesis was also included to explore similar projects on a larger scale conducted in Sweden, how the view of vanadium is from an EU perspective and how flow batteries can be a part of an energy system. The methods considered most promising is extraction from mineral mining and extraction from ashes. A planned production plant has been dimensioned for both processes of production and energy demand is calculated. The study showed that both processes are expected to produce vanadium below current purchase price, which would then contribute to a cheaper production cost of flow batteries. It turned out that the production of vanadium from ash extraction would be significantly reduced by moving the business to a developing country. The operation stage in the mining operation which accounts for the highest energy demand is the size reduction of the ore. In the extraction process of vanadium from ash, it is primarily the fusion furnace and the fly ash filter required which has the highest energy demand. The similar extraction projects investigated was, from ashes, the so-called SOTEX process in Stenungsund and the mineral mining process had the Ranstad project as reference. The EU approach to vanadium is currently that the metal is not classified as a critical raw material but if economic instability would occur in any of the major manufacturing countries it would be considered as a more critical raw material. Flow batteries functioning as energy storage in a PV hybrid system was investigated and it was concluded that flow batteries are technically well suited for energy storage in this type of system. / Då samhället strävar efter att övergå till en hållbar energiproduktion är det en stor utmaning att effektivisera och utveckla den förnyelsebara energiproduktion som idag finns, både när det gäller enskilda komponenter och deras samspel i hela energisystem. Produktion från förnyelsebara energikällor sker ofta ojämnt och inte alltid när behovet uppstår. Genom att kunna lagra den överskottsenergi som produceras och sedan leverera den då behovet uppstår medför det till ett mer hållbart energisystem. Flödesbatterier är en möjlig teknik för lagring av energi. En viktig komponent i flödesbatterierna är vanadin och att hitta metoder för att utvinna vanadin på ett ekonomiskt sätt är ett viktigt steg i utvecklingen av denna teknik. Idén bakom examensarbetet var därför att kartlägga olika utvinningsmetoder för vanadin där de mest lovande metoderna, från ett ekonomiskt och energi perspektiv, undersöks mer utförligt. Vanadinet i sin tur ska sedan användas till elektrolyt i flödesbatterier. Det har även undersökts hur kostnaden påverkas av att flytta en tänkt anläggning för utvinning ur aska till ett utvecklingsland med lägre personalkostnader. I examensarbetet ingick även att undersöka liknande projekt i större skala som bedrivits i Sverige, hur synen på vanadin är ur ett EU perspektiv samt hur flödesbatterier kan vara en del av ett energisystem. De metoder som ansetts mest lovande är utvinning från mineralbrytning samt utvinning ur aska. En tänkt produktionsanläggning har dimensionerats för båda processer där produktionskostnad och energiförbrukning beräknats. Studien visade att båda processerna förväntas kunna producera vanadin under dagens inköpspris vilket då skulle bidra till en billigare produktionskostnad för flödesbatterier. Det visade sig att produktionen av vanadin ur askutvinning skulle minskas avsevärt genom att flytta verksamheten till ett utvecklingsland. Det moment i gruvdriften som står för största energiförbrukningen är storleksreduceringen av den malm som bryts. Vid processen för utvinning av vanadin ur aska är det främst den smältningsugn samt det filter för flygaska som krävs. De liknande projekt som verkat inom utvinning ur aska var den s.k. SOTEX processen i Stenungsund och för mineralbrytning har Ranstad projektet undersökts. EU:s syn på vanadin är i nuläget att metallen inte klassas som en kritisk råvara men om ekonomisk instabilitet skulle uppstå i något av de större tillverkande länderna skulle råvaran klassas som mer kritisk. Flödesbatteri fungerande som energilagring i ett förnyelsebart energisystem undersöktes där slutsatsen var att flödesbatterier tekniskt sett är mycket väl lämpade som energilagring i denna typ av system.

No description available.

The domestic sector will play an important role in the decarbonisation and decentralisation of the energy sector in the future. Installation numbers of building-integrated small-scale energy systems such as photovoltaics (PV), wind turbines and micro-combined heat and power (CHP) have significantly increased. However, the power output of PV and wind turbines is inherently linked to weather conditions; thus, the injected power into the public grid can be highly intermittent. With the increasing share of renewable energy at all voltage levels challenges arise in terms of power stability and quality. To overcome the volatility of such energy sources, storage technologies can be applied to temporarily decouple power generation from power consumption. Two emerging storage technologies which can be applied at residential level are hydrogen systems and vanadium-redox-flow-batteries (VRFB). In addition, the building-integrated energy sources and storage system can be combined to form a hybrid renewable energy system (HRES) to manage the energy flow more efficiently. The main focus of this thesis is to investigate the dynamic performance of two emerging energy storage technologies, a hydrogen loop composed of alkaline electrolyser, gas storage and proton exchange membrane (PEM) fuel cell, and a VRFB. In addition, the application of building-integrated HRES at customer level to increase the self-consumption of the onsite generated electricity and to lower the grid interaction of the building has been analysed. The first part deals with the development of a research test-bed known as the Hybrid Renewable Energy Park (HREP). The HREP is a residential-scale distributed energy system that comprises photovoltaic, wind turbine, CHP, lead acid batteries, PEM fuel cell, alkaline electrolyser and VRFB. In addition, it is equipped with programmable electronic loads to emulate different energy consumption patterns and a charging point for electric vehicles. Because of its modular structure different combinations of energy systems can be investigated and it can be easily extended. A unified communication channel based on the local operating network (LON) has been established to coordinate and control the HREP. Information from the energy systems is gathered with a temporal resolution of one second. Integration issues encountered during the integration process have been addressed. The second part presents an experimental methodology to assess the steady state and dynamic performance of the electrolyser, the fuel cell and the VRFB. Operational constrains such as minimum input/output power or start-up times were extracted from the experiments. The response of the energy systems to single and multiple dynamic events was analysed, too. The results show that there are temporal limits for each energy system, which affect its response to a sudden load change or the ability to follow a load profile. Obstacles arise in terms of temporal delays mainly caused by the distributed communication system and should be considered when operating or simulating a HRES at system level. The third part shows how improved system models of each component can be developed using the findings from the experiments. System models presented in the literature have the shortcoming that operational aspects are not adequately addressed. For example, it is commonly assumed that energy systems at system level can respond to load variations almost instantaneously. Thus, component models were developed in an integrated manner to combine theoretical and operational aspects. A generic model layout was defined containing several subsystems, which enables an easy implementation into an overall simulation model in MATLAB®/Simulink®. Experimental methods were explained to extract the new parameters of the semi-empirical models and discrete operational aspects were modelled using Stateflow®, a graphical tool to formulate statechart diagrams. All system models were validated using measured data from the experimental analysis. The results show a low mean-absolute-percentage-error (<3%). Furthermore, an advanced energy management strategy has been developed to coordinate and to control the energy systems by combining three mechanisms; statechart diagrams, double exponential smoothing and frequency decoupling. The last part deals with the evaluation, operation and control of HRES in the light of the improved system models and the energy management strategy. Various simulated case studies were defined to assess a building-integrated HRES on an annual basis. Results show that the overall performance of the hydrogen loop can be improved by limiting the operational window and by reducing the dynamic operation. The capability to capture the waste heat from the electrolyser to supply hot water to the residence as a means of increasing the overall system efficiency was also determined. Finally, the energy management strategy was demonstrated by real-time experiments with the HREP and the dynamic performance of the combined operation has been evaluated. The presented results of the detailed experimental study to characterise the hydrogen loop and the VRFB as well as the developed system models revealed valuable information about their dynamic operation at system level. These findings have relevance to the future application and for simulation studies of building-integrated HRES. There are still integration aspects which need to be addressed in the future to overcome the proprietary problem of the control systems. The innovations in the HREP provide an advanced platform for future investigations such as electric-vehicles as decentralised mobile storage and the development of more advanced control approaches.

Carbon nanotubes (CNTs) have been assessed for their use in electrochemical energy storage applications, namely Hydrogen Storage and Vanadium Redox Flow Batteries. Furthermore;fundamental electrochemical studies have been conducted on aligned arrays of carbon nanotubes, and for the first time electrochemistry on pure, defect free, single layer graphene is reported. CNTs have been assessed for their potential as an electrochemical hydrogen storage material,finding a maximum recorded capacity for a single walled nanotube sample (SWNT) that was comparable to literature gas phase adsorption values. In-situ Raman spectroelectrochemistry was used to probe structural changes of the SWNTs with applied potential: no chemical functionalisation of the tubes or intercalation of protons was observed. It was concluded, therefore, that CNTs present no unique electrochemical hydrogen storage ability, other than their role as an adsorbent for gaseous hydrogen, which was evolved electrochemically. CNTs were also assessed as a possible electrode material for the VO(2+)/VO2(+) reaction, used in the positive half cell of commercial vanadium redox flow batteries and widely reported to exhibit quasi-reversible kinetics on carbon electrodes. Initial investigations revealed apparently reversible kinetics using a SWNT, the first time such a response has been observed on Carbon, and in contradiction to published work using CNTs for this application. Analysis via a range of electrochemical techniques highlighted the difficulty in using cyclic voltammetry to assess reversibility, particularly for CNT modified electrodes. The system was subsequently found to be quasi-reversible, with the deceptively small peak separation inferred to arise from the pores of the CNT electrode, therefore thin layer cell behaviour was observed. The porous contribution was confirmed using an electrode exhibiting poor kinetics (very small, indistinct Faradaic peaks), increasing the electrode porosity (using an aligned array of CNT) had a remarkable effect, with large Faradaic peaks (low separation ˜ 0.02-0.04 V) observed for a sample that was chemically identical. This work highlights the fundamental error in a portion of CNT literature, where kinetic enhancement is quantified by voltammetric peak separation, which can be erroneous unless the inherent porosity of the electrodes is considered. In contrast to the complexity of CNTs, graphene represents an ideal electrode material, allowing for direct determination of the electrochemical response of the graphene basal plane, eliminating the contribution of edge sites. An initial investigation towards this goal is presented.

With its long cycle life and scalable design, the vanadium redox flow battery (VRB) is a promising technology for grid energy storage. However, high materials costs have impeded its commercialization. An essential but costly component of the VRB is the ion-exchange membrane. The ideal VRB membrane provides a highly conductive path for protons, prevents crossover of reactive species, and is tolerant of the acidic and oxidizing chemical environment of the cell. In order to study membrane performance and optimize cell design, mathematical models of the separator membrane have been developed. Where previous VRB membrane models considered minimal details of membrane transport, generally focusing on conductivity or self-discharge at zero current, the model presented here considers coupled interactions between each of the major species by way of rigorous material balances and concentrated solution theory. The model describes uptake and transport of sulfuric acid, water, and vanadium ions in Nafion membranes, focusing on operation at high current density. Governing equations for membrane transport are solved in finite difference form using the Newton-Raphson method. Model capabilities were explored, leading to predictions of Ohmic losses, vanadium crossover, and electro-osmotic drag. Experimental methods were presented for validating the model and for further improving estimates of uptake parameters and transport coefficients. / text

A comparison between a traditional fixed high voltage direct current energy transmission system and a mobile transmission system utilizing vanadium redox flow batteries has been conducted in this degree work.  The purpose of this comparison was to evaluate if a mobile energy transmission system could be competitive in terms of energy efficiency and cost-effectiveness for use in offshore wind power applications. A literary study was made to fully grasp the various technologies and to create empirical ground of which cost estimation methods and energy calculations could be derived. A specific scenario was designed to compare the two transmission systems with the same conditions. To perform the comparison, a model was designed and simulated in MATLAB. The results from the model showed that the flow battery system fell behind in energy efficiency with a total energy loss of 33.3 % compared to the 11.7 % of the traditional system, future efficiency estimations landed it at a more competitive 17.5 %. The techno-economic results proved that a mobile flow battery system would be up to nine times more expensive in comparison to a traditional transmission system, with the best-case scenario resulting in it being roughly two times more expensive. The main cause of this was found out to be the expensive energy subsystem, specifically the electrolyte, used in the flow battery system. Several environmental risks arise when using a flow battery system with this electrolyte as well which could harm marine life severely. In conclusion; with further development and cost reductions, a case could be made for the advantages of a truly mobile energy transmission system. Specifically, in terms of the pure flexibility and mobility of the system, allowing it to circumvent certain complications. The mobility of the system gives the possibility of selling energy where the spot prices are at their highest, providing a higher revenue potential compared to a traditional fixed system. As for now though, it is simply too expensive to be a viable solution.

Continued emission of green house gases has energized research activity worldwide to develop efficient ways to harness renewal energy. The availability of large scale energy storage technologies is essential to make renewal energy a reliable source of energy. Redox flow batteries show potential in this direction. These batteries typically need expensive membranes which need replacement be-cause of fouling. The recently proposed soluble lead redox flow battery (SLRFB), in which lead ions deposit on electrodes in charge cycle and dissolve back in discharge cycle, can potentially cut down the cost of energy storage by eliminating membrane. A number of challenges need to be overcome though. Low cycleability, residue formation, and low efficiencies are foremost among these, all of which require an understanding of the underlying mechanisms. A model of laminar flow-through SLRFB is first developed to understand buildup of residue on electrodes with continued cycling. The model accounts for spatially and temporally growing concentration boundary layers on electrodes in a self consistent manner by permitting local deposition/dissolution rates to be controlled by local ion transport and reaction conditions. The model suggests controlling role for charge transfer reaction on electrodes (anode in particular) and movement of ions in the bulk and concentration boundary layers. The non-uniform current density on electrodes emerges as key to formation of bare patches, steep decrease in voltage marking the end of discharge cycle, and residue buildup with continuing cycles. The model captures the experimental observations very well, and points to improved operational efficiency and decreased residue build up with cylindrical electrodes and alternating flow direction of recirculation. The underlying mechanism for more than an order of magnitude increase in cycle life of a beaker cell battery with increase in stirrer speed is unraveled next. Our experiments show that charging with and without stirring occurs identically, which brings up the hitherto unknown but quite strong role of natural convection in SLRFB. The role of stirring is determined to be dislodgement/disintegration of residue building up on electrodes. The depletion of active material from electrolyte due to residue formation is offset by “internal regeneration mechanism”, unraveled in the present work. When the rate of residue formation, rate of dislodging/disintegration from electrode, and rate of regeneration of active material in bulk of the electrolyte becomes equal, perpetual operation of SLRFB is expected. The identification of strong role of free convection in battery is put to use to demonstrate a battery that requires stirring/mixing only intermittently, during open circuit stages between charge and discharge cycles when no current is drawn. Inspired by our experimental finding that the measured currents for apparently diffusion limited situations (no external flow) are far larger than the maxi-mum possible theoretical value, the earlier model is modified to account for natural convection driven by concentration gradient of lead ions in electrolyte. The model reveals the presence of strong natural convection in battery. The induced flow in the vicinity of the electrodes enhances mass transport rates substantially, to the extent that even in the absence of external flow, normal charge/discharge of battery is predicted. The model predicted electrochemical characteristics are verified quantitatively through voltage-time measurements. The formation of flow circulation loops driven by electrode processes is validated qualitatively through PIV measurements. Natural convection is predicted to play a significant role in the presence of external flow as well. The hitherto unexplained finding in the literature on insensitivity of charge-discharge characteristics to electrolyte flow rate is captured by the model when mixed mode of convection is invoked. Flow reversal and wavy flow are predicted when natural convection and forced convection act in opposite directions in the battery. The effect of the presence of non-conducting material (PbO on anode) on the performance of SLRFB is studied using a simplified approach in the model. The study reveals the presence of charge coup de fouet phenomenon in charge cycle. The phenomenon as well as the predicted effect of depth of discharge on the magnitude of charge coup de fouet are confirmed experimentally.

[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