• Title, Summary, Keyword: Electrolyte Additive

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The Effect of Additives on the Performance of Aqueous Organic Redox Flow Battery Using Quinoxaline and Ferrocyanide Redox Couple (수계 유기 레독스 흐름 전지 성능에서의 첨가제 효과)

  • Chu, Cheonho;Lee, Wonmi;Kwon, Yongchai
    • Korean Chemical Engineering Research
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    • v.57 no.6
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    • pp.847-852
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    • 2019
  • In this study, the effect of additives on the performance of aqueous organic redox flow battery (AORFB) using quinoxaline and ferrocyanide as active materials in alkaline supporting electrolyte is investigated. Quinoxaline shows the lowest redox potential (-0.97 V) in KOH supporting electrolyte, while when quinoxaline and ferrocyanide are used as the target active materials, the cell voltage of this redox combination is 1.3 V. When the single cell tests of AORFBs using 0.1 M active materials in 1 M KCl supporting electrolyte and Nafion 117 membrane are implemented, it does not work properly because of the side reaction of quinoxaline. To reduce or prevent the side reaction of quinoxaline, the two types of additives are considered. They are the potassium sulfate as electrophile additive and potassium iodide as nucleophilie additive. Of them, when the single cell tests of AORFBs using potassium iodide as additive dissolved in quinoxaline solution are performed, the capacity loss rate is reduced to $0.21Ah{\cdot}L^{-1}per\;cycle$ and it is better than that of the single cell test of AORFB operated without additive ($0.29Ah{\cdot}L^{-1}per\;cycle$).

Electrodeposition of Cobalt Nanowires

  • Ahn, Sungbok;Hong, Kimin
    • Bulletin of the Korean Chemical Society
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    • v.34 no.3
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    • pp.927-930
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    • 2013
  • We developed an electroplating process of cobalt nanowires of which line-widths were between 70 and 200 nm. The plating electrolyte was made of $CoSO_4$ and an organic additive, dimethyldithiocarbamic acid ester sodium salt (DAESA). DAESA in plating electrolytes had an accelerating effect and reduced the surface roughness of plated cobalt thin films. We obtained void-free cobalt nanowires when the plating current density was 6.25 mA/$cm^2$ and DAESA concentration was 1 mL/L.

Cross-linkable Polymer Matrix for Enhanced Thermal Stability of Succinonitrile-based Polymer Electrolyte in Lithium Rechargeable Batteries

  • Ryou, Myung-Hyun;Lee, Dong-Jin;Lee, Je-Nam;Lee, Hong-Kyeong;Seo, Myung-Won;Lee, Hye-Won;Shin, Weon-Ho;Lee, Yong-Min;Choi, Jang-Wook;Park, Jung-Ki
    • Journal of Electrochemical Science and Technology
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    • v.2 no.4
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    • pp.198-203
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    • 2011
  • A polymer electrolyte was prepared by using polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) or poly(ethylene glycol) dimethacrylate (PEGDMA) as polymer matrices, succinonitrile as an additive, and lithium perchlorate as a lithium salt. Compared to the polymer electrolyte employing PVdF-HFP, the PEGDMA-based polymer electrolyte exhibits substantially superior thermal stability when exposed to high temperatures. Nonetheless, the ionic conductivity of the PEGDMA-based polymer electrolyte was preserved in a wide temperature range between $-20^{\circ}C$ and $80^{\circ}C$.

Effect of KOH Electrolyte and H2O2 Depolarizer on the Power Characteristics of Al/Air Fuel Cells (Al/Air 연료전지의 출력특성에 미치는 KOH 전해질과 H2O2 감극제의 영향)

  • Kim, Yong-Hyuk
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.4
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    • pp.303-307
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    • 2015
  • The effects of additive such as $H_2O_2$ in KOH electrolyte solution for the Aluminum/Air fuel cell were investigated with regard to electric power characteristics. The power generated by a Al/Air fuel cell was controlled by the KOH electrolyte solution and $H_2O_2$ depolarizer. Higher cell power was achieved when higher KOH electrolyte concentration and higher $H_2O_2$ depolarizer amount. The maximum power was increased by the increase amount $H_2O_2$ depolarizer, it was found that $H_2O_2$ depolarizer inhibits the generation of hydrogen and the polarization effect was reduced as a result. Internal resistance analysis was employed to elucidate the maximum power variation. Higher internal resistance created internal potential differences that drive current dissipating energy. In order to improve the output characteristics of the Al/Air fuel cell, it is thought to be desirable to increase the KOH electrolyte concentration and increase the $H_2O_2$ addition amounts.

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 $HSO_3Cl$.

High Temperature Stable Eletrolyte for Dye Solar Cell (염료태양전지용 고온안정성 전해질)

  • Han, Chi-Hwan;Lee, Hak-Soo
    • 한국태양에너지학회:학술대회논문집
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    • pp.220-224
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    • 2009
  • The effect of addition of single and binary additives on the performance of dye-sensitized $TiO_2$ solar cells based on 1,2-dimethyl-3-propylimidazolium iodide (DMPII) in ethylene carbonate (EC) and gamma-butyrolactone (GBL) has been evaluated at different cell temperatures in the $30-120^{\circ}C$ range. The electrolyte containing a single additive, 2-(dimethylamino)-pyridine (DMAP) showed best performance, which showed further enhancement for an electrolyte containing binary additives, DMAP and 5-chloro-1-ethyl-2-methylimidazole (CEMI) in equal molar ratio. The performance of the dye sensitized solar cell (DSC) based on electrolyte containing binary additives were found to be better than an acetonitrile based electrolyte. The dependence of different photovoltaic parameters (Voc, Jsc, ff, n) of the DSC upon temperature has been studied over the $30-120^{\circ}C$ range and only a small decrease in conversion efficiency has been observed. Thus the electrolyte containing binary additives (DMAP, CEMI) in EC/GBL solvent and show better performance in the investigated temperature range ($30-120^{\circ}C$).

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Enhancement of surface stability of lithium manganese oxide spinel by silyl-group functionalized fluoride-responsive ionic liquid additives

  • Seo, Hyoree;Na, Subin;Lee, Boeun;Yim, Taeeun;Oh, Si Hyoung
    • Journal of Industrial and Engineering Chemistry
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    • v.64
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    • pp.311-317
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    • 2018
  • Spinel-structured lithium manganese oxides are considered as promising cathode material, however, their widespread commercial application remains hampered by their poor surface instability. To overcome these problems, we designed and synthesized task-specific ionic liquid additives that can effectively scavenge trace amounts of fluoride in the cell. Addition of ionic liquid additives in the electrolyte significantly improves cycling retention. $^1H-$ and $^{19}F-nuclear$ magnetic resonance spectroscopy measurements and inductively coupled plasma mass spectrometry elemental analysis collaboratively provides clear evidence that the ionic liquid additives selectively suppress parasitic reactions of the electrolyte with the surface of lithium manganese oxides cathode.

The Micro Coil Production through Research on the Additive Conditions of Electrochemical Metal 3D Printer (전기화학적 금속 3D 프린터의 적층 조건 연구를 통한 마이크로 코일 제작)

  • Kim, Young-Kuk;Kang, Donghwa;Kim, Sung-Bin;Yoo, Bongyoung
    • Journal of the Korean institute of surface engineering
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    • v.53 no.4
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    • pp.138-143
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    • 2020
  • In this study, we produced a coil of micro-pattern that can be used for electromagnetic wave absorber, heating material, wireless charging, sensor, antenna, etc. by using electrochemical additive manufacturing method. Currently, it contains research contents for manufacturing a micro pattern coil having practicality through control of process control variables such as applied voltage, distance between electrode, and nozzle injection. Circulation of the electrolyte through the nozzle injection control can significantly contribute to improving the surface characteristics of the coil because of minimizing voltage fluctuations that may occur during the additive manufacturing process. In addition, by applying the pulse method in the application of voltage, the lamination characteristics of the plated body were improved, which showed that the formation of a fine line width plays an important role in the production of a micro pattern coil. By applying the pulse signal to the voltage application, the additive manufacturing characteristics of the produced product were improved, and it was shown that the formation of a fine line width plays an important role in the production of a micro pattern coil.

Characterization of SEI layer for Surface Modified Cathode of Lithium Secondary Battery Depending on Electrolyte Additives (전해질 첨가제에 따른 graphite 음극의 SEI분석 및 전기 화학적 특성 고찰)

  • Lee, Sung Jin;Cha, Eun Hee;Lim, Soo A
    • Journal of the Korean Electrochemical Society
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    • v.19 no.3
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    • pp.69-79
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    • 2016
  • Lithium ion battery with high energy density is expanding its application area to electric automobile and electricity storage field beyond existing portable electric devices. Such expansion of an application field is demanding higher characteristic and stable long life characteristic of an anode material, the natural graphite that became commercialized in lithium ion battery. This thesis produced cathode by using natural graphite anode material, analyzed creation of the cathode SEI film created due to initial reaction by using electrolyte additives, VC (vinylene carbonate), VEC (vinyl ethylene carbonate), and FEC (fluoroethylene carbonate), and considered correlation with the accompanying electrochemical transformation. This study compared and analyzed the SEI film variation of natural graphite cathode according to the electrolyte additive with SEI that is formed at the time of initial filling and cathode of $60^{\circ}C$ life characteristic. At the time of initial filling, the profile showed changes due to the SEI formation, and SEI was formed in No-Additive in approximately 0.9 V through EVS, but for VC, VEC, and FEC, the formation reaction was created above 1 V. In $60^{\circ}C$ lifespan characteristic evaluation, the initial efficiency was highest in No-Additive and showed high contents percentage, but when cycle was progressed, the capacity maintenance rate decreased more than VC and FEC as the capacity and efficiency at the time of filling decreased, and VEC showed lowest performance in efficiency and capacity maintenance rate. Changes of SEI could not be verified through SEM, but it was identified that as the cycle of SEI ingredients was progressed through FT-IR, ingredients of Alkyl carbonate ($RCO_2Li$) affiliation of the $2850-2900cm^{-1}$ was maintained more solidly and the resistance increased as cycle was progressed through EIS, and specially, it was identified that the resistance due to No-Additive and SEI of VEC became very significant. Continuous loss of additives was verified through GC-MS, and the loss of additives from partial decomposition and remodeling of SEI formed the non-uniform surface of SEI and is judged to be the increase of resistance.