Performance enhancement of vanadium redox flow battery by optimized electrode compression and operational conditions

J, Charvát; Mazúr, Petr; Dundálek, Jan; Pocedič, Jaromír; Vrána, Jiří; Mrlík, Jindřich; Košek, Juraj; Dinter, Saskia

doi:10.1016/j.est.2020.101468

Cited by 32 publications

(22 citation statements)

References 29 publications

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“…It is worth to note that the initial R CT is significantly higher when compared to our std. vanadium RFB full-cell where we have observed R CT of 0.1 Ohm cm 2 with the same electrodes and comparable concentration of active compound (1.6 mol dm −3 of vanadium ion for 1 e – process) [ 22 ]. This is slightly surprising as according to the literature AQDS is supposed to exhibit much faster electron transfer kinetics when compared to both VRFB reactions [ 5 ].…”

Section: Resultsmentioning

confidence: 99%

“…vanadium RFB full-cell where we have observed RCT of 0.1 Ohm cm 2 with the same electrodes and comparable concentration of active compound (1.6 mol dm −3 of vanadium ion for 1 eprocess). [22] This is slightly surprising as according to the literature AQDS is supposed to exhibit much faster electron transfer kinetics when compared to both VRFB reactions. [5] The higher activation polarization of AQDS-based DHC can be related to the mutual interactions of AQDS molecules in concentrated solution (initially concentration of 0.86 mol dm −3 ).…”

Section: Dhc Parameters Evolutionmentioning

confidence: 95%

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Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Mazúr

Mrlík

et al. 2021

Molecules

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Despite intense research in the field of aqueous organic redox flow batteries, low molecular stability of electroactive compounds limits further commercialization. Additionally, currently used methods typically cannot differentiate between individual capacity fade mechanisms, such as degradation of electroactive compound and its cross-over through the membrane. We present a more complex method for in situ evaluation of (electro)chemical stability of electrolytes using a flow electrolyser and a double half-cell including permeation measurements of electrolyte cross-over through a membrane by a UV–VIS spectrometer. The method is employed to study (electro)chemical stability of acidic negolyte based on an anthraquinone sulfonation mixture containing mainly 2,6- and 2,7-anthraquinone disulfonic acid isomers, which can be directly used as an RFB negolyte. The effect of electrolyte state of charge (SoC), current load and operating temperature on electrolyte stability is tested. The results show enhanced capacity decay for fully charged electrolyte (0.9 and 2.45% per day at 20 °C and 40 °C, respectively) while very good stability is observed at 50% SoC and lower, even at 40 °C and under current load (0.02% per day). HPLC analysis conformed deep degradation of AQ derivatives connected with the loss of aromaticity. The developed method can be adopted for stability evaluation of electrolytes of various organic and inorganic RFB chemistries.

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Section: Resultsmentioning

confidence: 99%

Section: Dhc Parameters Evolutionmentioning

confidence: 95%

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Mazúr

Mrlík

et al. 2021

Molecules

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“…The requirement for extremely high ionic conductivities in a technical flow battery can be highlighted in a comparison with a conventional lithium ion battery (LIB). In a flow battery, the electrolytes are flown through the porous electrodes with a thickness of some mm [48]. In some special flow field designs, the gap can be reduced to close to 1 mm or even below, but nevertheless, a certain gap is required to maintain the flow.…”

Section: Ionic Conductivitymentioning

confidence: 99%

Family Tree for Aqueous Organic Redox Couples for Redox Flow Battery Electrolytes: A Conceptual Review

2022

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Redox flow batteries (RFBs) are an increasingly attractive option for renewable energy storage, thus providing flexibility for the supply of electrical energy. In recent years, research in this type of battery storage has been shifted from metal-ion based electrolytes to soluble organic redox-active compounds. Aqueous-based organic electrolytes are considered as more promising electrolytes to achieve “green”, safe, and low-cost energy storage. Many organic compounds and their derivatives have recently been intensively examined for application to redox flow batteries. This work presents an up-to-date overview of the redox organic compound groups tested for application in aqueous RFB. In the initial part, the most relevant requirements for technical electrolytes are described and discussed. The importance of supporting electrolytes selection, the limits for the aqueous system, and potential synthetic strategies for redox molecules are highlighted. The different organic redox couples described in the literature are grouped in a “family tree” for organic redox couples. This article is designed to be an introduction to the field of organic redox flow batteries and aims to provide an overview of current achievements as well as helping synthetic chemists to understand the basic concepts of the technical requirements for next-generation energy storage materials.

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“…While, fitting parameters I Loss , U 0 , and R i always have fixed values during one step s (Figure 6, orange colored loop), C Stor is varied in a defined ranges listed in Table 6. The variable stepsize defines the amount of values in vector C Stor (k) and is used to calculate the stepvalue in accordance with Equation (6). As discussed above, the state parameters are assessed with different values before the optimization function is applied to the VRFB model.…”

Section: Boundary Conditions Of Optimization Process and State Variable Definitionmentioning

confidence: 99%

“…During the last decade, vanadium redox flow batteries (VRFB), developed and patented in 1980s by M. Skyllar-Kazacos et al [2], have drawn attention especially for large storage applications. Since then, many research groups have been focused on improving VRFB materials [3][4][5][6][7][8], control algorithms [9][10][11][12][13][14][15] and on techno-economic analysis [16][17][18][19]. Compared to other electrochemical EES, VRFB show technical and ecological benefits.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Input Parameter Variation on the Accuracy of a Vanadium Redox Flow Battery Simulation Model

et al. 2021

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Accurately predicting battery behavior, while using low input data, is highly desirable in embedded simulation architectures like grid or integrated energy system analysis. Currently, the available vanadium redox flow battery (VRFB) models achieve highly accurate predictions of electrochemical behavior or control algorithms, while the optimization of the required input data scope is neglected. In this study, a parametrization tool for a DC grey box simulation model is developed using measurements with a 10 kW/100 kWh VRFB. An objective function is applied to optimize the required input data scope while analyzing simulation accuracy. The model is based on a differential-algebraic system, and an optimization process allows model parameter estimation and verification while reducing the input data scope. Current losses, theoretical storage capacity, open circuit voltage, and ohmic cell resistance are used as fitting parameters. Internal electrochemical phenomena are represented by a self-discharge current while material related losses are represented by a changing ohmic resistance. Upon reducing input data the deviation between the model and measurements shows an insignificant increase of 2% even for a 60% input data reduction. The developed grey box model is easily adaptable to other VRFB and is highly integrable into an existing energy architecture.

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Performance enhancement of vanadium redox flow battery by optimized electrode compression and operational conditions

Cited by 32 publications

References 29 publications

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Family Tree for Aqueous Organic Redox Couples for Redox Flow Battery Electrolytes: A Conceptual Review

The Effect of Input Parameter Variation on the Accuracy of a Vanadium Redox Flow Battery Simulation Model

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