Special Issue "Vanadium Redox Flow Battery and Its Applications"

A special issue of Batteries (ISSN 2313-0105).

Deadline for manuscript submissions: 31 December 2018

Special Issue Editor

Guest Editor
Prof. Dr. Maria Skyllas-Kazacos

School of Chemical Engineering, University of New South Wales (UNSW Sydney) NSW, Australia, 2052
Website | E-Mail
Interests: vanadium redox flow battery; flow batteries; electrode materials; membranes; cell design; sensors; control; modelling; simulation

Special Issue Information

Dear Colleagues,

It has now been more than 30 years since the first patent on the Vanadium Redox Flow Battery (VFB) was granted to our group at University of New South Wales (UNSW Sydney) and we are thrilled to see the increasing interest that has led to the extensive research, development, field trials and now commercial production of the VFB around the world. VFB can now be regarded as a mature energy storage technology, but, as with all mature technologies, ongoing research is helping to improve performance and reduce cost for broader implementation in a range of energy storage applications. In this first Special Issue dedicated to the Vanadium Redox Flow Battery, we hope to collect contributions from all the research groups and companies currently engaged in VFB research, development and manufacture in order to describe the current state-of-the-art across the full range of flow battery topics to serve as an important reference to the energy storage industry and to flow battery researchers engaged in this rapidly growing field.

Prof. Dr. Maria Skyllas-Kazacos
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Batteries is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) is waived for well-prepared manuscripts submitted to this issue. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • vanadium electrolytes
  • electrolyte production methods
  • electrode materials
  • membranes
  • sensors
  • stack design and modelling
  • cell materials
  • simulation
  • advanced control
  • cost analysis
  • manufacturing
  • quality control
  • field studies
  • system design
  • performance evaluation

Published Papers (8 papers)

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Research

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Open AccessArticle Verification of Redox Flow Batteries’ Functionality by Electrochemical Impedance Spectroscopy Tests
Received: 28 September 2018 / Revised: 24 October 2018 / Accepted: 30 October 2018 / Published: 6 November 2018
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Abstract
The state-of-the-art functionality test of classic redox-flow-stacks measures the current–voltage characteristic with the technical electrolyte. This research paper aims to simplify the validation of redox flow batteries’ functionality by conducting electrochemical impedance spectroscopy (EIS) on redox flow stacks. Since the electrolyte used in
[...] Read more.
The state-of-the-art functionality test of classic redox-flow-stacks measures the current–voltage characteristic with the technical electrolyte. This research paper aims to simplify the validation of redox flow batteries’ functionality by conducting electrochemical impedance spectroscopy (EIS) on redox flow stacks. Since the electrolyte used in the batteries is usually toxic and aggressive, it would be a significant simplification to verify the functionality with an alternative, non-toxic fluid. EIS measurements on batteries with larger sized electrodes, multiple cells, and different fluids were performed. It was demonstrated that all impedances are repeatable, thereby validating this procedure as a qualification method for full-size and complex batteries with an alternative fluid. EIS measurements were able to detect deliberately manipulated cells. This research uses three different analysis methods for the acquired data to identify errors. The respective approaches are, firstly, (1) a comparison of the Nyquist plots; secondly, (2) a comparison of the Bode plots; and thirdly, (3) a comparison of the calculated characteristic values of the equivalent circuits. The analysis found that all methods are suitable to detect errors in the batteries. Nevertheless, the bode-plot comparison method proves to be especially advantageous, because it enables a quantitative statement. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Open AccessArticle Conversion of Spent Coffee Beans to Electrode Material for Vanadium Redox Flow Batteries
Received: 6 September 2018 / Revised: 12 October 2018 / Accepted: 22 October 2018 / Published: 1 November 2018
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Abstract
This study presents the application of pyrolyzed spent coffee beans as a potential electrode material to replace commercial bipolar graphite plate in vanadium redox flow batteries (VRB). The results indicate that the biochar obtained from spent coffee beans shows relatively good electrochemical charge
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This study presents the application of pyrolyzed spent coffee beans as a potential electrode material to replace commercial bipolar graphite plate in vanadium redox flow batteries (VRB). The results indicate that the biochar obtained from spent coffee beans shows relatively good electrochemical charge transfer kinetics of vanadium redox reactions as well as generates higher energy and voltage efficiency in a static cell test when compared to TF6 bipolar graphite plate. Additionally, the biochar was activated via steam at various activation times to increase its surface area, and their effect on the kinetics of the electrochemical reactions was investigated. The activated carbon did not exhibit any improvement neither in electron transfer kinetics nor in the battery efficiency, despite their increased surface area. The performed studies demonstrate that the biochar obtained from spent coffee beans can be a low-cost electrode material for VRB with improved performance characteristics. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Open AccessCommunication Effect of Operating Temperature on Individual Half-Cell Reactions in All-Vanadium Redox Flow Batteries
Received: 26 September 2018 / Revised: 29 October 2018 / Accepted: 30 October 2018 / Published: 1 November 2018
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Abstract
Systematic steady-state measurements were performed in order to investigate the effect of operating temperature on the individual half-cell reactions in all vanadium redox flow cells. Results confirm that the kinetic losses are dominated by the negative half-cell reaction. Steady-state polarization and AC impedance
[...] Read more.
Systematic steady-state measurements were performed in order to investigate the effect of operating temperature on the individual half-cell reactions in all vanadium redox flow cells. Results confirm that the kinetic losses are dominated by the negative half-cell reaction. Steady-state polarization and AC impedance measurements allowed for extraction of kinetic parameters (exchange current densities, activation energy) of the corresponding half-cell reaction. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Open AccessArticle Characterisation of a 200 kW/400 kWh Vanadium Redox Flow Battery
Received: 30 September 2018 / Revised: 20 October 2018 / Accepted: 22 October 2018 / Published: 1 November 2018
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Abstract
The incessant growth in energy demand has resulted in the deployment of renewable energy generators to reduce the impact of fossil fuel dependence. However, these generators often suffer from intermittency and require energy storage when there is over-generation and the subsequent release of
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The incessant growth in energy demand has resulted in the deployment of renewable energy generators to reduce the impact of fossil fuel dependence. However, these generators often suffer from intermittency and require energy storage when there is over-generation and the subsequent release of this stored energy at high demand. One such energy storage technology that could provide a solution to improving energy management, as well as offering spinning reserve and grid stability, is the redox flow battery (RFB). One such system is the 200 kW/400 kWh vanadium RFB installed in the energy station at Martigny, Switzerland. This RFB utilises the excess energy from renewable generation to support the energy security of the local community, charge electric vehicle batteries, or to provide the power required to an alkaline electrolyser to produce hydrogen as a fuel for use in fuel cell vehicles. In this article, this vanadium RFB is fully characterised in terms of the system and electrochemical energy efficiency, with the focus being placed on areas of internal energy consumption from the regulatory systems and energy losses from self-discharge/side reactions. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Open AccessArticle Variable Porous Electrode Compression for Redox Flow Battery Systems
Received: 28 September 2018 / Revised: 16 October 2018 / Accepted: 19 October 2018 / Published: 22 October 2018
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Abstract
Vanadium redox flow batteries (VRFBs) offer great promise as a safe, cost effective means of storing electrical energy on a large scale and will certainly have a part to play in the global transition to renewable energy. To unlock the full potential of
[...] Read more.
Vanadium redox flow batteries (VRFBs) offer great promise as a safe, cost effective means of storing electrical energy on a large scale and will certainly have a part to play in the global transition to renewable energy. To unlock the full potential of VRFB systems, however, it is necessary to improve their power density. Unconventional stack design shows encouraging possibilities as a means to that end. Presented here is the novel concept of variable porous electrode compression, which simulations have shown to deliver a one third increase in minimum limiting current density together with a lower pressure drop when compared to standard uniform compression cell designs. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Open AccessCommunication Novel Approaches for Solving the Capacity Fade Problem during Operation of a Vanadium Redox Flow Battery
Received: 10 August 2018 / Revised: 11 September 2018 / Accepted: 12 September 2018 / Published: 1 October 2018
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Abstract
The vanadium redox flow battery (VRFB) is one of the most mature and commercially available electrochemical technologies for large-scale energy storage applications. The VRFB has unique advantages, such as separation of power and energy capacity, long lifetime (>20 years), stable performance under deep
[...] Read more.
The vanadium redox flow battery (VRFB) is one of the most mature and commercially available electrochemical technologies for large-scale energy storage applications. The VRFB has unique advantages, such as separation of power and energy capacity, long lifetime (>20 years), stable performance under deep discharge cycling, few safety issues and easy recyclability. Despite these benefits, practical VRFB operation suffers from electrolyte imbalance, which is primarily due to the transfer of water and vanadium ions through the ion-exchange membranes. This can cause a cumulative capacity loss if the electrolytes are not rebalanced. In commercial systems, periodic complete or partial remixing of electrolyte is performed using a by-pass line. However, frequent mixing impacts the usable energy and requires extra hardware. To address this problem, research has focused on developing new membranes with higher selectivity and minimal crossover. In contrast, this study presents two alternative concepts to minimize capacity fade that would be of great practical benefit and are easy to implement: (1) introducing a hydraulic shunt between the electrolyte tanks and (2) having stacks containing both anion and cation exchange membranes. It will be shown that the hydraulic shunt is effective in passively resolving the continuous capacity loss without detrimentally influencing the energy efficiency. Similarly, the combination of anion and cation exchange membranes reduced the net electrolyte flux, reducing capacity loss. Both approaches work efficiently and passively to reduce capacity fade during operation of a flow battery system. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Open AccessArticle The Effect of Sulfuric Acid Concentration on the Physical and Electrochemical Properties of Vanadyl Solutions
Received: 30 May 2018 / Revised: 19 July 2018 / Accepted: 23 July 2018 / Published: 1 September 2018
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Abstract
The effects of sulfuric acid concentration in VO2+ solutions were investigated via electrochemical methods and electron paramagnetic resonance. The viscosity of solutions containing 0.01 M VOSO4 in 0.1–7.0 M H2SO4 was measured. Diffusion coefficients were independently measured via
[...] Read more.
The effects of sulfuric acid concentration in VO2+ solutions were investigated via electrochemical methods and electron paramagnetic resonance. The viscosity of solutions containing 0.01 M VOSO4 in 0.1–7.0 M H2SO4 was measured. Diffusion coefficients were independently measured via electrochemical methods and electron paramagnetic resonance (EPR), with excellent agreement between the techniques employed and literature values. Analysis of cyclic voltammograms suggest the oxidation of VO2+ to VO2+ is quasi-reversible at high H2SO4 concentrations (>5 mol/L), and approaching irreversible at lower H2SO4 concentrations. Further analysis reveals a likely electrochemical/chemical (EC) mechanism where the H2SO4 facilitates the electrochemical step but hinders the chemical step. Fundamental insights of VO2+/H2SO4 solutions can lead to a more comprehensive understanding of the concentration effects in electrolyte solutions. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Review

Jump to: Research

Open AccessReview Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries
Received: 30 July 2018 / Revised: 20 August 2018 / Accepted: 23 August 2018 / Published: 13 September 2018
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Abstract
Flow batteries (also: redox batteries or redox flow batteries RFB) are briefly introduced as systems for conversion and storage of electrical energy into chemical energy and back. Their place in the wide range of systems and processes for energy conversion and storage is
[...] Read more.
Flow batteries (also: redox batteries or redox flow batteries RFB) are briefly introduced as systems for conversion and storage of electrical energy into chemical energy and back. Their place in the wide range of systems and processes for energy conversion and storage is outlined. Acceleration of electrochemical charge transfer for vanadium-based redox systems desired for improved performance efficiency of these systems is reviewed in detail; relevant data pertaining to other redox systems are added when possibly meriting attention. An attempt is made to separate effects simply caused by enlarged electrochemically active surface area and true (specific) electrocatalytic activity. Because this requires proper definition of the experimental setup and careful examination of experimental results, electrochemical methods employed in the reviewed studies are described first. Full article
(This article belongs to the Special Issue Vanadium Redox Flow Battery and Its Applications)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Degradation phenomena of bismuth-modified felt electrodes in VRFB studied by EIS and XPS

Authors: Jonathan Schneider, Eduard Bulczak, Igor Derr, Konstantin Schutjajew, Abdulmonem Fetyan, Christina Roth
Affiliations: Institute for Chemistry and Biochemistry, FU Berlin, Takustr. 3, D-14195 Berlin
Abstract: The performance of all-V redox flow batteries (VRFB) will decrease when they are exposed to dynamic electrochemical cycling, but also when they are in prolonged contact with the acidic electrolyte. These phenomena are especially severe at the negative side, where the parasitic hydrogen evolution reaction (HER) will be increasingly favored over the reduction of V(III) with ongoing degradation of the carbon felt electrode. Bismuth, either added to the electrolyte or deposited onto the felt, has been reported to suppress the HER and therefore to enhance the kinetics of the V(II)/V(III) redox reaction. This study is the first to investigate degradation effects on bismuth-modified electrodes in the negative half-cell of a VRFB. By means of a simple impregnation method, a commercially available carbon felt was decorated with Bi2O3, which is supposedly present as Bi(0) under the working conditions at the negative side. Modified and unmodified felts were electrochemically characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a three-electrode setup. This was done before and after the electrodes were subjected to electrochemical cycling for more than two weeks in a battery test bench. The fiber composition of the felt electrodes close to the surface was probed using X-ray photoelectron spectroscopy (XPS) and correlated with the electrochemical results. Based on these findings, the effect of bismuth on the degradation of carbon felt electrodes in the negative half cell of VRFB is discussed.
Keywords: Vanadium, redox flow battery, degradation, bismuth, electrochemical impedance spectroscopy

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