• Title/Summary/Keyword: Vanadium electrolyte

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The Electrolyte Flow Rate Effect on the Performance of a Vanadium Redox Flow Battery (VRFB) (바나듐레독스흐름전지의 전해질의 유량 변화에 따른 성능 영향성)

  • YECHAN PARK;SUNHOE KIM
    • Transactions of the Korean hydrogen and new energy society
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    • v.33 no.6
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    • pp.803-807
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    • 2022
  • In this study, the battery performance change according to the change of electrolyte flow rate. With increase of electrolyte flow rate the energy efficiency showed tendency of decrease. The electrochemical impedance spectroscopy results showed the increased resistance.

Effect of Electrolyte Flow Rates on the Performance of Vanadium Redox Flow Battery (바나듐레독스흐름전지 전해질 유량에 따른 성능변화)

  • LEE, KEON JOO;KIM, SUNHOE
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.4
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    • pp.324-330
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    • 2015
  • The electrolyte flow rates of vanadium redox flow battery play very important role in terms of ion transfer to electrolyte, kinetics and pump efficiency in system. In this paper a vanadium redox flow battery single cell was tested to suggest the optimization criteria of electrolyte flow rates on the efficiencies. The compared electrolyte circulation flow rates in this experimental work were 15, 30 and 45 mL/min. The charge/discharge characteristics of the flow rate of 30 mL/min was the best out of all flow rates in terms of charging and discharging time. The current efficiencies, voltage efficiencies and energy efficiencies at the flow rate of 30 mL/min were the best. The IR losses obtained at thd current density of $40mA/cm^2$, at the flow rates of 15, 30 and 45 mL/min were 0.085 V, 0.042 V and 0.115 V, respectively. The charge efficiencies at the current density of $40mA/cm^2$ were 96.42%, 96.45% and 96.29% for the electrolyte flow rates of 15, 30 and 45 mL/min, respectively. The voltge efficiencies at the current density of $40mA/cm^2$ were 77.34%, 80.62% and 76.10% for the electrolyte flow rates of 15, 30 and 45 mL/min, respectively. Finally, the energy efficiencies at the current density of $40mA/cm^2$ were 74.57%, 77.76% and 73.27% for the electrolyte flow rates of 15, 30 and 45 mL/min, respectively. The optimum flow rates of electrolytes were 20 mL/min in most of operating variables of vanadium redox flow battery.

Study on the Electrolyte Added Chlorosulfuric Acid for All-vanadium Redox Flow Battery (바나듐 레독스 흐름 전지용 전해액으로 클로로황산 첨가에 관한 연구)

  • OH, YONG-HWAN;LEE, GEON-WOO;RYU, CHEOL-HWI;HWANG, GAB-JIN
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.2
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    • pp.169-175
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    • 2016
  • The electrolyte added the chlorosulfuric acid ($HSO_3Cl$) as an additive was tested for the electrolyte in all-vanadium redox flow battery (VRFB) to increase the thermal stability of electrolyte. The electrolyte property was measured by the CV (cyclic voltammetry) method. The maximum value of a voltage and current density in the electrolyte added $HSO_3Cl$ was higher than that in the electrolyte non-added $HSO_3Cl$. The thermal stability of the pentavalent vanadium ion solution, which was tested at $40^{\circ}C$, increased by adding $HSO_3Cl$. The performances of VRFB using the electrolyte added and non-added $HSO_3Cl$ were measured during 30 cycles of charge-discharge at the current density of $60mA/cm^2$. An average energy efficiency of the VRFB was 72.5%, 82.4%, and 81.6% for the electrolyte non-added $HSO_3Cl$, added 0.5 mol of $HSO_3Cl$, and added 1.0 mol of $HSO_3Cl$, respectively. VRFB using the electrolyte added $HSO_3Cl$ was showed the higher performance than that using the electrolyte non-added $HSO_3Cl$.

Anodic Growth of Vanadium Oxide Nanostructures (Vanadium Oxide 나노구조 형성)

  • Lee, Hyeon-Gwon;Lee, Gi-Yeong
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.68-68
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    • 2018
  • Nanoporous or nanotubular metal oxide can be fabricated by anodization of metal substrate in fluoride contained electrolytes. The approach allows various transition metals such as Zr, Hf, Nb, Ta to form highly ordered oxide nanostructures. These oxide nanostructures have various advantages such as high surface area, fast electron transport rate and slow recombination in semiconductive materials. Recently, vanadium oxide nanostructures have been drawn attentions due to their superior electronic, catalytic and ion insertion properties. However, anodization of vanadium metal to form oxide layers is relatively difficult due to ease formation of highly soluble complex in water contained electrolyte during anodization. Yang et al. reported $[TiF_6]^{2-}$ or $[BF_4]^-$ in electrolyte helps to formation of stable oxide layer [1, 2]. However, the reported approaches are very sensitive in other parameters. In this presentation, we deal with the other important key parameters to form ordered anodic vanadium oxide such as pH, temperatures and applied potential.

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Preparation of V3.5+ Electrolyte for Vanadium Redox Flow Batteries using Carbon Supported Pt Dendrites Catalyst (카본 담지 백금 덴드라이트 촉매를 이용한 바나듐 레독스 흐름전지용 3.5가 바나듐 전해질의 제조)

  • Lee, Hojin;Kim, Hansung
    • Journal of the Korean Electrochemical Society
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    • v.24 no.4
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    • pp.113-119
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    • 2021
  • In this study, impurity free V3.5+ electrolytes were prepared using formic acid as a reducing agent and PtD/C as a catalyst and it was applied to VRFB. The well-oriented 3D dendrite structure of the PtD/C catalyst showed high catalytic activity in formic acid oxidation reaction and vanadium reduction reaction. As a result, the conversion ratio of electrolyte using the PtD/C was 2.73 mol g-1 h-1, which was higher than that of 1.67 mol g-1 h-1 of Pt/C prepared by the polyol method. In addition, in the VRFB charging and discharging experiment, the V3.5+ electrolyte produced by the catalytic reaction showed the same performance as the standard V3.5+ electrolyte prepared by the electrolytic method, thus proving that it can be used as an electrolyte for VRFB.

Characterization of Electric Double-Layer Capacitor with 0.75M NaI and 0.5 M VOSO4 Electrolyte

  • Chun, Sang-Eun;Yoo, Seung Joon;Boettcher, Shannon W.
    • Journal of Electrochemical Science and Technology
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    • v.9 no.1
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    • pp.20-27
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    • 2018
  • We describe a redox-enhanced electric double-layer capacitor (EDLC) that turns the electrolyte in a conventional EDLC into an integral, active component for charge storage-charge is stored both through faradaic reactions with soluble redox-active molecules in the electrolyte, and through the double-layer capacitance in a porous carbon electrode. The mixed-redox electrolyte, composed of vanadium and iodides, was employed to achieve high power density. The electrochemical reaction in a supercapacitor with vanadium and iodide was studied to estimate the charge capacity and energy density of the redox supercapacitor. A redox supercapacitor with a mixed electrolyte composed of 0.75 M NaI and 0.5 M $VOSO_4$ was fabricated and studied. When charged to a potential of 1 V, faradaic charging processes were observed, in addition to the capacitive processes that increased the energy storage capabilities of the supercapacitor. The redox supercapacitor achieved a specific capacity of 13.44 mAh/g and an energy density of 3.81 Wh/kg in a simple Swagelok cell. A control EDLC with 1 M $H_2SO_4$ yielded 7.43 mAh/g and 2.85 Wh/kg. However, the relatively fast self-discharge in the redox-EDLC may be due to the shuttling of the redox couple between the polarized carbon electrodes.

Fabrication and Electrochemical Characterization of All Solid State Thin Film Micro-Battery by in-situ sputtering (In-situ 스퍼터링을 이용한 마이크로 박막 전지의 제작 및 전지 특성 평가)

  • 전은정;신영화;남상철;조원일;손봉희;윤영수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.159-162
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    • 1999
  • All solid state thin film micro-batteries consisting of lithium metal anode, an amorphous LiPON electrolyte and cathode of vanadium oxide have been fabricated and characterized, which were fabricated with cell structure of Li/LiPON/V$_2$O$\sub$5/Pt. The vanadium oxide thin films were formed by d.c. reactive sputtering on Pt current collector. After deposition of vanadium oxide films, in-situ growths of lithium phosphorus oxynitride film were conducted by r.f. sputtering of Li$_3$PO$_4$ target in mixture gas of N$_2$ and O$_2$. The pure metal lithium film was deposited by thermal evaporation on thin film LiPON electrolyte. The cell capacity was about 45${\mu}$Ah/$\textrm{cm}^2$ $\mu\textrm{m}$ after 200 cycle. No appreciable degradation of the cell capacity could be observed after 50 cycles .

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Catalytic effects of heteroatom-rich carbon-based freestanding paper with high active-surface area for vanadium redox flow batteries

  • Lee, Min Eui;Kwak, Hyo Won;Jin, Hyoung-Joon
    • Carbon letters
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    • v.28
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    • pp.105-110
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    • 2018
  • Owing to their scalability, flexible operation, and long cycle life, vanadium redox flow batteries (VRFBs) have gained immense attention over the past few years. However, the VRFBs suffer from significant polarization, which decreases their cell efficiency. The activation polarization occurring during vanadium redox reactions greatly affects the overall performance of VRFBs. Therefore, it is imperative to develop electrodes with numerous catalytic sites and a long cycle life. In this study, we synthesized heteroatom-rich carbon-based freestanding papers (H-CFPs) by a facile dispersion and filtration process. The H-CFPs exhibited high specific surface area (${\sim}820m^2g^{-1}$) along with a number of redox-active heteroatoms (such as oxygen and nitrogen) and showed high catalytic activity for vanadium redox reactions. The H-CFP electrodes showed excellent electrochemical performance. They showed low anodic and cathodic peak potential separation (${\Delta}E_p$) values of ~120 mV (positive electrolyte) and ~124 mV (negative electrolyte) in cyclic voltammetry conducted at a scan rate of $5mV\;s^{-1}$. Hence, the H-CFP-based VRFBs showed significantly reduced polarization.

Effect of Electrolyte Additive on the Electrochemical Characteristics of Lithium Vanadium Oxide Anode (전해질 첨가제가 리튬 바나듐 옥사이드 전극의 성능에 미치는 영향)

  • Lee, Je-Nam
    • Journal of the Korean Electrochemical Society
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    • v.21 no.3
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    • pp.55-60
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    • 2018
  • The demand for LIBs with higher energy densities has increased continuously because the emergence of wider and more challenging applications including HEV and EV has became imperative. However, in the case of anode material, graphite is insufficient to meet this need. To meet such demand, several type of negative electrode materials like silicon, tin, SiO, and transition metal oxide have been investigated for the advanced lithium secondary batteries. Recently, lithium vanadium oxide, which has a layered structure, is assumed as one of the promising anode material as alternative of graphite. This material shows a high volumetric capacity, which is 1.5 times higher than that of graphite. However, relative low electrical conductivity and particle fracture, which results in the electrolyte decomposition and loss of electric contact between electrode, induce rapid capacity decay. In this report, we investigated the effect of electrolyte additive on the electrochemical characteristics of lithium vanadium oxide.

Study on the Vanadium Redox Flow Battery using Cation Exchange Membrane and Ammonium Metavanadate (메타바나듐산암모늄과 양이온교환막을 활용한 바나듐 레독스 흐름전지에 관한 연구)

  • Jung, Bo-Young;Ryu, Cheol-Hwi;Hwang, Gab-Jin
    • Membrane Journal
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    • v.31 no.4
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    • pp.262-267
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    • 2021
  • The electrochemical performance of all vanadium redox flow battery (VRFB) using an electrolyte prepared from ammonium metavanadate and a cation exchange membrane (Nafion117) was evaluated. The electrochemical performance of VRFB was measured at a current density of 60 mA/cm2. The average current efficiency of VRFB using the electrolyte prepared from ammonium metavanadate was 94.9%, the average voltage efficiency was 82.2%, and the average energy efficiency was 78.0%. In addition, it was confirmed that the efficiencies of VRFB using the electrolyte prepared from ammonium metavanadate had almost the same value as the efficiencies of VRFB using the electrolyte prepared with vanadyl sulfate (VOSO4).