Vanadium (V) reduction reaction on modified glassy carbon electrodes – Role of oxygen functionalities and microstructure

Taylor, Susan M.; Pătru, Alexandra; Streich, Daniel; Kazzi, Mario El; Fabbri, Emiliana; Schmidt, Thomas J.

doi:10.1016/j.carbon.2016.08.044

Cited by 38 publications

(33 citation statements)

References 35 publications

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“…A model involving electron transfer through a layer of adsorbed vanadium accounting for this observation has been proposed. The effect of various mechanical as well as chemical surface treatment methods on the electroreduction of V(V) ions has been examined [207]. No correlation between oxygen content and catalytic activity was found.…”

Section: Catalysis Catalysts and Electrode Materialsmentioning

confidence: 99%

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

Holze

2018

Batteries

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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.

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Section: Catalysis Catalysts and Electrode Materialsmentioning

confidence: 99%

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

Holze

2018

Batteries

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“…As this is the case in all-vanadium RFBs, 15 considerable effort has been focused on modifying commercially available materials to increase active surface area, hydrophilicity, and/or catalytically-active surface functional groups. Indeed, a range of techniques including thermal activation, [16][17][18][19][20] acidic or basic treatment, [21][22][23] plasma activation, 24 and deposition of nanoparticles [25][26][27] have been successfully applied to carbon papers and felts, resulting in marked improvements in RFB performance due to reductions in charge transfer overpotential. While valid, these approaches are typically empirical, often relying on qualitative comparison of full cell polarization curves with pristine and modified materials, which belies the complex coupling of transport and reaction kinetics within the electrode that ultimately defines performance limits.…”

mentioning

confidence: 99%

Exploring the Role of Electrode Microstructure on the Performance of Non-Aqueous Redox Flow Batteries

Forner‐Cuenca

Penn

Oliveira

et al. 2019

J. Electrochem. Soc.

135

259

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Redox flow batteries are an emerging technology for long-duration grid energy storage, but further cost reductions are needed to accelerate adoption. Improving electrode performance within the electrochemical stack offers a pathway to reduced system cost through decreased resistance and increased power density. To date, most research efforts have focused on modifying the surface chemistry of carbon electrodes to enhance reaction kinetics, electrochemically active surface area, and wettability. Less attention has been given to electrode microstructure, which has a significant impact on reactant distribution and pressure drop within the flow cell.Here, drawing from commonly used carbon-based diffusion media (paper, felt, cloth), we systematically investigate the influence of electrode microstructure on electrochemical performance. We employ a range of techniques to characterize the microstructure, pressure drop, and electrochemically active surface area in combination with in-operando diagnostics performed in a single electrolyte flow cell using a kinetically facile redox couple dissolved in a non-aqueous electrolyte. Of the materials tested, the cloth electrode shows the best performance; the highest current density at a set overpotential accompanied by the lowest hydraulic resistance. We hypothesize that the bimodal pore size distribution and periodic, well-defined microstructure of the cloth are key to lowering mass transport resistance.

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“…However, surface modification leading to increased roughness and number of defects appeared to play a positive role for this reaction. 21 Many recent studies focusing on both vanadium redox reactions involved in the VRB have shown that the overpotential associated with the negative half-cell dominates the voltage losses of the VRB and limits performance. …”

mentioning

confidence: 99%

Performance of Different Carbon Electrode Materials: Insights into Stability and Degradation under Real Vanadium Redox Flow Battery Operating Conditions

Nibel

Taylor

Pătru

et al. 2017

J. Electrochem. Soc.

Self Cite

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This work focuses on the performance and stability of selected commercial carbon electrode materials before and after heat-treatment in an operating all-vanadium redox flow battery (VRB). Heat treatment results in improved cell performance for all tested materials, with SGL 39 AA carbon papers and SIGRACELL GFD4.6 EA carbon felt showing the best performance. Further investigation of these two materials by in situ reference electrode measurements reveal improvements after heat-treatment that originate mainly from the negative electrode or V 2+ /V 3+ side of the cell. Upon extended cycling, carbon felt is found to be stable. Carbon papers however, show significant performance losses originating from the negative electrode side. The potential limit during charging and the exposure to very negative potentials appears to be a critical issue at the negative electrode in the VRB. Analysis of both materials after cycling by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy reveal significant differences in their surface chemistry, structure and morphology. These differences give valuable insights into the behavior and degradation of different carbon materials used in VRBs. Redox flow batteries (RFBs) are a promising technology for efficient energy storage and grid stabilization.1,2 The all-vanadium redox flow battery (VRB), which uses vanadium ions in different oxidation states at the positive and negative electrodes, is the most advanced RFB to date.3 The electrodes are a crucial component of the VRB, as they provide the surface on which the respective electrochemical reactions occur. Thus, catalytic activity, wettability and mass transport properties of the electrodes strongly affect VRB performance. Ideal electrodes for the VRB should provide both: long term durability and stable catalytic activity. Various materials have been considered as electrodes for the use in VRBs including non-carbon based dimensionally stable anode electrodes and carbon based electrodes such as carbon felt, carbon paper, carbon nanotubes, carbon nanofibers or graphene oxides. 4 To enhance electrochemical activity and wettability of carbon based materials in VRBs, different surface modification methods have been used. Carbon electrodes have been coated with metals such as iridium, 5 doped with nitrogen 6 or decorated with nanomaterials such as graphene-nanowalls 7 or graphite carbon nanotubes. Most of these surface treatment approaches introduce functional groups, commonly oxygen onto the carbon electrode surface. This leads to increased wettability and redox activity, which is generally attributed to the increased concentration of surface-active oxygen functional groups.11 Among the various surface modifications, heattreatment is still regarded as the most common and facile approach to incorporate oxygen groups onto the surface of carbon materials. 4 In an effort to better understand the role of oxygen functional groups on electrode performance, Fink et al. studied pristine and heat-treated Rayon (a regene...

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Vanadium (V) reduction reaction on modified glassy carbon electrodes – Role of oxygen functionalities and microstructure

Cited by 38 publications

References 35 publications

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

Exploring the Role of Electrode Microstructure on the Performance of Non-Aqueous Redox Flow Batteries

Performance of Different Carbon Electrode Materials: Insights into Stability and Degradation under Real Vanadium Redox Flow Battery Operating Conditions

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