• Proceedings of the Safety Management and Science Conference
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• 2002.11a
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• pp.279-284
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• 2002

All-vanadium redox flow battery(VRFB) has been studied actively as one of the most promising electrochemical energy storage systems for a wide range of applications such as electric vehicles, photovoltaic arrays, and excess power generated by electric power plants at night time. CPCS has been shown to have the characteristics as an excellent current collector for VRFB and electrochemical properties of specific resistivity 0.31 $\Omega$cm, which were composed of G-1028 80 wt%, PVC 10 wt%, DBP 5 wt% and FS 5 wt%. Energy efficiencies of VRFB with the CPCE and the existing electrode assembly were 84.14 % and 77.24 % respectively, in charge/discharge experiments at constant current of 200 mA, and the CPCE was confirmed to be suitable as the electrode of VRFB.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.408-412
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• 2019

In this study, nitrogen doped carbon felt was prepared by pyrolysis of urea at high temperature and applied as an electrode for vanadium redox flow cell. Urea is easier to handle than ammonia and forms $NH_2$ radicals at higher temperatures, creating a nitrogen functional group on the carbon surface and acting as an active site in the vanadium redox reaction. Therefore, the discharge capacity of activated carbon felt electrodes using urea was 14.9 Ah/L at a current density of $150mA/cm^2$, which is 23% and 187% higher than OGF and GF, respectively. These results show the possibility that activated carbon felt electrode using urea can be used as electrode material for redox flow battery.

• 한국전기화학회:학술대회논문집
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• 2002.10a
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• pp.56-56
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• 2002

• 한국전기화학회:학술대회논문집
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• 2000.10a
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• pp.34-34
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• 2000

• Composites Research
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• v.37 no.3
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• pp.190-196
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• 2024

The bipolar plate is a crucial element of the vanadium redox flow battery (VRFB) as it serves as both the electrical conduit and the structural support for the cell within the VRFB stack. Although, the graphite material is primarily used for the bipolar plate due to its excellent electrical conductivity, a significant limitation of performance of the VRFB is present due to high interfacial contact resistance (ICR) arises between the electrode and bipolar plate in the cell stack. This study aims to develop an integrated electrode-bipolar plate assembly that will address the limitations of the ICR. The integrated assembly was constructed using a single carbon felt with thermoplastic and thermoset polymers utilizing hot press method. Experimental results verify that the bipolar plate assembly exhibits reduced area specific resistance (ASR) due to the continuous electrical path. Additionally, from the charge/discharge cell test results, the integrated assembly shows improved cell performance. Therefore, the developed integrated electrode-bipolar plate assembly can serve as a substitute for the conventional bipolar plate and electrode assembly.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.12
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• pp.74-83
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• 2014

This paper proposes a study on the configuration of balancing of plant(BOP) and implementation of battery management system(BMS) functions for vanadium redox flow battery(VRFB) and propose a method consists of sensor and required design specifications BOP system configuration. And it proposes an method of the functions implementation and control algorithm of the BMS for flow battery. Functions of BMS include temperature control, the charge and discharge control, flow control, level control, state of charge(SOC) estimation and a battery protection through the sensor signal of BOP. Functions of BMS is implemented by the sensor signal, so it is recognized as a very important factor measurement accuracy of the data. Therefore, measuring a mechanical signal(flow rate, temperature, level) through the BOP test model, and the measuring an electrical signal(cell voltage, stack voltage and stack current) through the VRFB charge-discharge system and analyzes the precision of data in this paper. Also it shows a good charge-discharge test results by the SOC estimation algorithm of VRFB. Proposed BOP configuration and BMS functions implementation can be used as a reference indicator for VRFB system design.

• Journal of Electrochemical Science and Technology
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• v.14 no.2
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• pp.131-138
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• 2023

The carbon felt is usually hired as electrodes for vanadium redox flow battery (VRFB). In the study, surface modification of carbon felt under CO₂ atmosphere with variables of operating various temperature ranges between 700℃ and 900℃. The qualitative and quantitative analysis were carried out such as scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) to observe degree of surface modification. Result of XPS analysis confirmed increase of carbon and oxidation functional group on the surface with increase of temperature. SEM image was discovered similar phenomena. Electrochemical characteristics such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) revealed the improved electrode performance with increase of temperature. However, the electrochemical performance under treatments temperature of 900℃ was less than that of under treatment temperature of 850℃ due to weight loss at the treatment temperature of 900℃. From the CV and EIS results, the best electrochemical characteristics was at the temperature of 850℃. That of at the temperature of 900℃ was decreased due to weight loss. The energy efficiencies (EE) obtained from full cell test were 69.37, 80.76, 82.45, and 75.47%, at the temperature of 700, 800, 850, and 900℃, respectively.

• Journal of Electrochemical Science and Technology
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• v.12 no.3
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• pp.330-338
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• 2021

An integral electrode-bipolar plate assembly, which is composed of electrode, conductive adhesive film (CAF) and bipolar plate, has been developed and evaluated for application with a vanadium redox flow battery (VRB) to decrease contact resistance between electrode and bipolar plate. The CAF, made of EVA (ethylene-vinyl-acetate) material with carbon black or CNT (Carbon Nano Tube), is applied between the electrode and the bipolar plate to enable an integral assembly by adhesion. In order to evaluate the integral assembly of VRB by adhesive film, the resistivity of integral assembly and the performance of single cell were investigated. Thus, it was verified that the integral assembly is applicable to redox flow battery. Through resistance and contact resistance of bare EVA and CAF films on bipolar plate were changed. Among the adhesive films, CAF film coated with carbon black showed the lowest value in through resistance, and CAF film coated with CNT showed the lowest value in contact resistance, respectively. The efficiency of VRB single cell was improved by applying CAF films coated with carbon black and CNT, resulting in the reduced overvoltage in charging process. Therefore, the energy efficiency of both CAF films, about 84%, were improved than that of blank cell, about 79.5 % under current density at 40 mA cm^-2. The energy efficiency of the two cells were similar, but carbon black coated CAF improved the coulomb efficiency and CNT coated CAF improved the voltage efficiency, respectively.

• Analytical Science and Technology
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• v.28 no.5
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• pp.341-346
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• 2015

In order to understand the counter anionic effects in a non-aqueous vanadium redox flow battery (VRFB), we synthesized four types of electrolyte salts (1-ethyltriethamine tertafluoroborate, [E-TEDA]⁺[BF₄]⁻, 1-ethyltriethamine hexafluorophosphate, [E-TEDA]⁺[PF₆]⁻, 1-butyltriethylamine tertafluoroborate, [B-TEDA]⁺[BF₄]⁻, and 1-buthyltriethamine hexafluorophosphate [B-TEDA]⁺[PF₆]⁻) by counter anion exchange reaction after the SN₂ reaction. We confirmed the successful synthesis of the electrolyte salts [E-TEDA]⁺[Br]⁻ and [B-TEDA]⁺[Br]⁻ via ¹H-NMR spectroscopy and GC-mass analysis before the counter anion exchange reaction. The electric potential of the vanadium acetylacetonate, V(acac)₃, as an energy storage chemical was shown to be 2.2 V in the acetonitrile solvent with each of the [E-TEDA]⁺[BF₄]⁻, [E-TEDA]⁺[PF₆]⁻, [B-TEDA]⁺[BF₄]⁻, and [B-TEDA]⁺[PF₆]⁻ electrolyte salts. In a non-aqueous VRFB with a commercial Neosepta AFN membrane, the maximum voltages reached 1.0 V and 1.5 V under a fixed current value of 0.1 mA in acetonitrile with the [E-TEDA]⁺[BF₄]⁻ and [E-TEDA]⁺[PF₆]⁻ electrolyte salts, respectively. The maximum voltage was 0.8 V and 1.1 V under a fixed current value of 0.1 mA in acetonitrile with the [B-TEDA]⁺[BF₄]⁻ and [B-TEDA]⁺[PF₆]⁻ electrolyte salts, respectively. From these results, we concluded that in the non-aqueous VRFB more of the [PF₆]⁻ counter anion than the [BF₄]⁻ counter anion was transported onto the commercial Neosepta AFN anion exchange membrane.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1267-1269
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• 2010

The pure crystalline $Li_{1.1}V_{0.9}O_2$ powder has been prepared by a simple solid state reaction of $Li_2CO_3$ and $V_2O_3$ precursors under nitrogen gas containing 10 mol % hydrogen gas flow. The structure of $Li_{1.1}V_{0.9}O_2$ powder was analyzed using Xray diffraction (XRD) and scanning electron microscope (SEM). The stoichiometric $Li_{1.1}V_{0.9}O_2$ powder was used as anode active material for lithium secondary batteries. Its electrochemical properties were investigated by cyclic voltammetry and constant current methods using lithium foil electrode. The observed specific discharge capacity and charge capacity were 360 mAh/g and 260 mAh/g during the first cycle, respectively. In addition, the cyclic efficiency of this cell was 72.2% in the first cycle. The specific capacity of $Li_{1.1}V_{0.9}O_2$ anode rapidly declines as the current rate increases and retains only 30 % of the capacity of 0.1C rate at 1C rate. The crystallinity of the $Li_{1.1}V_{0.9}O_2$ anode decrease as discharge reaction proceeds. However, the relative intensity of main peaks was almost recovered when the cell was charged up to 1.5 V.