Highly Hydroxylated Graphite Felts Used as Electrodes for a Vanadium Redox Flow Battery

The highly hydroxylated graphite felts (GFs) were obtained by treating in mixed acids (V(HNO3)/V(H3PO4)=3:1) for different time at 80°C, and used as the electrodes for all vanadium redox flow battery (VRB). The physical, chemical and electrochemical characteristics of these GFs are characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, cyclic voltametry, electrochemical impedance spectroscopy and charge/discharge test. The excellent electrochemical properties of the treated GFs to VRB electrode reactions can be ascribed to the enhancement of the interaction between vanadium ions with –OH groups introduced by acid treatment. Using GFs treated in the mixed acids for 8 h as electrodes, the VRB exhibits excellent performance under a current density of 20 mA/cm2. The average current efficiency, voltage efficiency and energy efficiency are about 97%, 83.3% and 78%, respectively.

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Electroless chemical aging of carbon felt electrodes for the all-vanadium redox flow battery (VRFB) investigated by Electrochemical Impedance and X-ray Photoelectron Spectroscopy

Electrochimica Acta ◽

10.1016/j.electacta.2017.06.050 ◽

2017 ◽

Vol 246 ◽

pp. 783-793 ◽

Cited By ~ 25

Author(s):

Igor Derr ◽

Daniel Przyrembel ◽

Jakob Schweer ◽

Abdulmonem Fetyan ◽

Joachim Langner ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Electrochemical Impedance ◽

Vanadium Redox Flow Battery ◽

Redox Flow Battery ◽

Carbon Felt ◽

Flow Battery ◽

Chemical Aging ◽

X Ray ◽

Vanadium Redox ◽

Felt Electrodes

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Thiourea-Grafted Graphite Felts as Positive Electrode for Vanadium Redox Flow Battery

Frontiers in Chemistry ◽

10.3389/fchem.2020.626490 ◽

2021 ◽

Vol 8 ◽

Author(s):

Shangzhuo Wu ◽

Xin Lv ◽

Zhijun Ge ◽

Ling Wang ◽

Lei Dai ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Positive Electrode ◽

Vanadium Redox Flow Battery ◽

Redox Flow Battery ◽

Peak Potential ◽

Flow Battery ◽

X Ray ◽

Vanadium Redox ◽

Acid Esterification ◽

Electro Catalytic Activity

In this paper, thiourea was successfully grafted onto the surface of acid preprocessed graphite felts [sulfuric acid-treated graphite felt (SA-GFs)] by thiol-carboxylic acid esterification. The thiourea-grafted graphite felts (TG-GFs) were investigated as the positive electrode for vanadium redox flow battery (VRFB). X-ray photoelectron spectroscopy results suggested that thiourea was grafted into the surface of graphite felts. The cyclic voltammetry showed that the peak potential separation decreased by 0.2 V, and peak currents were greatly enhanced on TG-GF electrode compared with SA-GF electrode, implying improved electro-catalytic activity and reversibility of TG-GF electrode toward VO2+/VO2+ redox reaction. The initial capacity of TG-GF-based cell reached 55.6 mA h at 100 mA cm−2, 22.6 mA h larger than that of SA-GF-based cell. The voltage and energy efficiency for TG-GF-based cell increased by 4.9% and 4.4% compared with those of SA-GF-based cell at 100 mA cm−2, respectively.

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Optimal Sizing of Vanadium Redox Flow Battery Systems for Residential Applications Based on Battery Electrochemical Characteristics

Energies ◽

10.3390/en9100857 ◽

2016 ◽

Vol 9 (10) ◽

pp. 857 ◽

Cited By ~ 9

Author(s):

Xinan Zhang ◽

Yifeng Li ◽

Maria Skyllas-Kazacos ◽

Jie Bao

Keyword(s):

Vanadium Redox Flow Battery ◽

Electrochemical Characteristics ◽

Redox Flow Battery ◽

Flow Battery ◽

Optimal Sizing ◽

Battery Systems ◽

Vanadium Redox

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Amphoteric Ion Exchange Membranes Prepared by Preirradiation-Induced Emulsion Graft Copolymerization for Vanadium Redox Flow Battery

Polymers ◽

10.3390/polym11091482 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1482 ◽

Cited By ~ 5

Author(s):

Yu Cui ◽

Xibang Chen ◽

Yicheng Wang ◽

Jing Peng ◽

Long Zhao ◽

...

Keyword(s):

Ion Exchange ◽

Photoelectron Spectroscopy ◽

Graft Copolymerization ◽

Open Circuit ◽

Vanadium Redox Flow Battery ◽

Ion Exchange Membranes ◽

Redox Flow Battery ◽

Flow Battery ◽

Aqueous Emulsion ◽

Vanadium Redox

A series of poly(vinylidene difluoride)-based amphoteric ion exchange membranes (AIEMs) were prepared by preirradiation-induced graft copolymerization of styrene and dimethylaminoethyl methacrylate in an aqueous emulsion media followed by solution casting, sulfonation, and protonation. The effects of absorbed dose and comonomer concentration on grafting yield (GY) were investigated. The highest GY of 44.5% at a low comonomer concentration of 0.9 M could be achieved. FTIR, TGA, and X-ray photoelectron spectroscopy (XPS) confirmed the successful grafting and sulfonation of the as-prepared AIEMs. Properties of the AIEMs such as water uptake, ion exchange capacity (IEC), ionic conductivity, and crossover behavior of VO2+ ions prepared by this novel technique were systematically investigated and compared with those of the commercial Nafion 115 membrane. It was found that at a GY of 28.4%, the AIEMs showed higher IEC and conductivity, lower permeability of VO2+ ions, and a longer time to maintain open circuit voltage than Nafion 115, which was attributed to their high GY and elaborate amphoteric structure. Consequently, this work has paved the way for the development of green and low-cost AIEMs with good performance for vanadium redox flow battery applications.

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On the resistances of a slurry electrode vanadium redox flow battery

10.31224/osf.io/pa98t ◽

2020 ◽

Author(s):

Matthias Wessling

Keyword(s):

Electrochemical Impedance ◽

Graphite Powder ◽

Electrode System ◽

Vanadium Redox Flow Battery ◽

Redox Flow Battery ◽

Flow Battery ◽

Half Cell ◽

Static Mixers ◽

System P ◽

Vanadium Redox

We studied the half cell performance of a slurry-based vanadium redox flow battery via the polarization and electrochemical impedance spectroscopymethods. First, the conductive static mixers are examined and lower ohmicand diffusion resistances are shown. Further analyses of the slurry electrodes for the catholyte (VO2+- VO2+) and anolyte (V3+- V2+) are presented for the graphite powder slurry containing up to 15.0 wt.% particle content. Overall, the anolyte persists as the more resistive half cell, while ohmic and diffusionrelated limitations are the dominating resistances for both electrolytes. The battery is further improved by the addition of Ketjen black nanoparticles, which results in lower cell resistances. The best results are achieved when 0.5 wt.% Ketjen black nanoparticles are dispersed with graphite powder since the addition of nanoparticles reduces ohmic, charge transfer and mass diffusion resistances by improving particle-particle dynamics. The results prove the importance of understanding resistances in a slurry electrode system.

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