• Title/Summary/Keyword: Electrolyte

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Performance of a Ceramic Fiber Reinforced Polymer Membrane as Electrolyte in Direct Methanol Fuel Cell

  • Nair, Balagopal N.;Yoshikawa, Daishi;Taguchi, Hisatomi
    • Membrane Journal
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    • v.14 no.1
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    • pp.53-56
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    • 2004
  • Direct Methanol Fuel Cell (DMFC) is considered as a candidate technology for applications in stationary, transportation as well as electronic power generation purposes. To develop a high performance direct methanol fuel cell(DMFC), a competent electrolyte membrane is needed. The electrolyte membrane should be durable and methanol crossover must be low. One of the approaches to increase the stability of generally used polymer electrolyte membranes such as Nafion against swelling or thermal degradation is to bond it with an inorganic material physically or chemically. In Noritake Company, we have developed a novel method of reinforcing the polymer electrolyte matrix with inorganic fibers. Methanol crossover values measured were significantly lower than the original polymer electrolyte membranes. These fiber reinforced electrolyte membranes (FREM) were used for DMFC study and stable power output values as high 160 mW/$\textrm{cm}^2$ were measured. The details of the characteristics of the membranes as well as I-V data of fuel cell stacks are detailed in the paper.

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 $HSO_3Cl$.

Analysis of Cell Performance with Varied Electrolyte Species and Amounts in a Molten Carbonate Fuel Cell

  • Lee, Ki-Jeong;Kim, Yu-Jeong;Koomson, Samuel;Lee, Choong-Gon
    • Journal of Electrochemical Science and Technology
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    • v.9 no.2
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    • pp.141-148
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    • 2018
  • This study evaluated the performance characteristics of varied electrolyte species and amounts in a molten carbonate fuel cell (MCFC). Coin-type MCFCs were used at the condition of $650^{\circ}C$ and 1 atm. In order to measure the effects of varied electrolyte species and amounts, electrolytes of $(Li+K)_2CO_3$ and $(Li+Na)_2CO_3$ were selected and the amounts of 1.5 g, 2.0 g, 3.0 g, and 4.0 g were used. Insignificant performance differences were observed in the cell using different electrolytes, but the cell performance was sensitive to the amount of the electrolyte used. The pore-filling ratio (PFR), a ratio of pore filling in the components by the liquid carbonate electrolytes, was used to determine the optimum performance range. Consequently, 77% PFR demonstrated the optimum performance for both electrolytes. Thus, the MCFC had a permissible but narrow optimum performance range. The remaining amounts of electrolyte in the cells were determined using the weight reduction ratio (WRR) method after several hours of cell operation. The WRR used the relationship between the initial loaded amount of electrolyte and weight reduction of components in 10 wt% acetic acid. The relationships were linear and identical between the two electrolyte species.

Electrochemical properties of metal salts polymer electrolyte for DSSC (금속염을 이용한 염료감응 태양전지의 고체전해질의 전기화학적 특성)

  • Zhao, Xing Guan;Jin, En Mei;Gu, Hal-Bon
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.55.1-55.1
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    • 2011
  • Dye-sensitized solar cell(DSSC) have been considered one of the promising alternatives to conventional solar cells, because of their low cost, easy fabrication and relatively high energy conversion efficiency. However, although the cell offers reasonable efficiency at least 11%, the use of a liquid electrolyte placed technological challenges for achieving the desired durability and operational stability of the cell. In order to prevent or reduce electrolyte leakage considerable efforts have been made, such as p-type semiconductor or organic hole-transport material that better mechanical properties and simple fabrication processes. In this work, we synthesized solid-state electrolyte containing LiI and KI metal salt with starting materials of poly ethylene oxide to substitute liquid electrolyte enhance the ionic conductivity and solar conversion efficiency. Li+ leads to faster diffusion and higher efficiency and K+ leading to higher ionic conductivity. The efficiency of poly ethylene oxide/LiI system electrolyte is 1.47% and poly ethylene oxide/potassium electrolyte is 1.21%. An efficiency of 3.24% is achieved using solid-state electrolyte containing LiI and KI concentrations. The increased solar conversion efficiency is attributed to decreased crystallinity in the polymer that leads to enhanced charge transfer.

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High Temperature Supercapacitor with Free Standing Quasi-solid Composite Electrolytes (독립형 반고체 복합 전해질을 적용한 고온 수퍼커패시터)

  • Kim, Dong Won;Jung, Hyunyoung
    • Korean Journal of Materials Research
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    • v.29 no.2
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    • pp.121-128
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    • 2019
  • Supercapacitors are attracting much attention in sensor, military and space applications due to their excellent thermal stability and non-explosion. The ionic liquid is more thermally stable than other electrolytes and can be used as a high temperature electrolyte, but it is not easy to realize a high temperature energy device because the separator shrinks at high temperature. Here, we report a study on electrochemical supercapacitors using a composite electrolyte film that does not require a separator. The composite electrolyte is composed of thermoplastic polyurethane, ionic liquid and fumed silica nanoparticles, and it acts as a separator as well as an electrolyte. The silica nanoparticles at the optimum mass concentration of 4wt% increase the ionic conductivity of the composite electrolyte and shows a low interfacial resistance. The 5 wt% polyurethane in the composite electrolyte exhibits excellent electrochemical properties. At $175^{\circ}C$, the capacitance of the supercapacitor using our free standing composite electrolyte is 220 F/g, which is 25 times higher than that at room temperature. This study has many potential applications in the electrolyte of next generation energy storage devices.

Triphenyl phosphate as an Efficient Electrolyte Additive for Ni-rich NCM Cathode Materials

  • Jung, Kwangeun;Oh, Si Hyoung;Yim, Taeeun
    • Journal of Electrochemical Science and Technology
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    • v.12 no.1
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    • pp.67-73
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    • 2021
  • Nickel-rich lithium nickel-cobalt-manganese oxides (NCM) are viewed as promising cathode materials for lithium-ion batteries (LIBs); however, their poor cycling performance at high temperature is a critical hurdle preventing expansion of their applications. We propose the use of a functional electrolyte additive, triphenyl phosphate (TPPa), which can form an effective cathode-electrolyte interphase (CEI) layer on the surface of Ni-rich NCM cathode material by electrochemical reactions. Linear sweep voltammetry confirms that the TPPa additive is electrochemically oxidized at around 4.83 V (vs. Li/Li+) and it participates in the formation of a CEI layer on the surface of NCM811 cathode material. During high temperature cycling, TPPa greatly improves the cycling performance of NCM811 cathode material, as a cell cycled with TPPa-containing electrolyte exhibits a retention (133.7 mA h g-1) of 63.5%, while a cell cycled with standard electrolyte shows poor cycling retention (51.3%, 108.3 mA h g-1). Further systematic analyses on recovered NCM811 cathodes demonstrate the effectiveness of the TPPa-based CEI layer in the cell, as electrolyte decomposition is suppressed in the cell cycled with TPPa-containing electrolyte. This confirms that TPPa is effective at increasing the surface stability of NCM811 cathode material because the TPPa-initiated POx-based CEI layer prevents electrolyte decomposition in the cell even at high temperatures.

EFFECTS OF LYSINE LEVEL AND NA+K-CI RATIO ON LUSINE-ARGININE ANTAGONISM, BLOOD pH, BLOOD ACID-BASE PARAMETERS AND GROWTH PERFORMANCE IN BROILER CHICKS

  • Kim, H.W.;Han, I.K.;Choi, Y.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.2 no.1
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    • pp.7-16
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    • 1989
  • To determine the effect of sodium plus potassium to chloride ratio and lysine level on blood pH, blood acid-base parameters, lysine-arginine antagonism and growth performance, four hundred and thirty two chicks of 3 days age were used in a completely randomized $3{\times}3$ factorial experiment. Variables contained three levels of lysine (0.8, 1.2 and 1.6%) and dietary electrolyte (100, 200 and 300 mEq/kg). Birds fed 200 mEq/kg and electrolyte had the best growth rate and feed efficiency, followed by those fed 300 mEq/kg and 100 mEq/kg electrolyte. It is proposed that high levels of dietary electrolyte may improve the growth of chicks fed diets containing excess lysine by increasing lysine catabolism. High or low levels of lysine and dietary electrolyte resulted in higher mortality than those of optimum level (1.2%) of lysine and 200 mEq/kg of electrolyte balance. When the electrolyte level was increased, the pH, $pCO_2$, base excess, $HCO_3{^-}$ and total $CO_2$ of blood plasma were increased. The utilization of nutrients was changed when the electrolyte and lysine were manipulated. Plasma chloride tended to be greater in chicks receiving high chloride diet and was the highest in chicks fed the high lysine diet. Plasma sodium and potassium were unaffected by dietary lysine. Diet containing high lysine decreased the level of arginine and excess dietary electrolyte increased arginine level in plasma. It may be concluded that cation supplementation tended to alleviate the lysine-arginine antagonism but chloride exacerbated. Tibia bone length and ash contents were significantly affected by electrolyte balance and lysine level.

Electrochemical Properties of Cathode according to the Type of Sulfide Electrolyte and the Application of Surface Coating

  • Yoon, Da Hye;Park, Yong Joon
    • Journal of Electrochemical Science and Technology
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    • v.12 no.1
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    • pp.126-136
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    • 2021
  • The electrochemical performance of all-solid-state cells (ASSCs) based on sulfide electrolytes is critically affected by the undesirable interfacial reactions between oxide cathodes and sulfide electrolytes because of the high reactivity of sulfide electrolytes. Based on the concept that the interfacial reactions are highly dependent on the type of sulfide electrolyte, the electrochemical properties of the ASSCs prepared using three types of sulfide electrolytes were observed and compared. The Li2MoO4-LiI coating layer was also introduced to suppress the interfacial reactions. The cells using argyrodite electrolyte exhibited a higher capacity and Coulombic efficiency than the cells using 75Li2S-22P2S5-3Li2SO4 and Li7P3S11 electrolytes, indicating that the argyrodite electrolyte is less reactive with cathodes than other electrolytes. Moreover, the introduction of Li2MoO4-LiI coating on the cathode surface significantly enhanced the electrochemical performance of ASSCs because of the protection of coating layer. Pulverization of argyrodite electrolyte is also effective in increasing the capacity of cells because the smaller size of electrolyte particles improved the contact stability between the cathode and the sulfide electrolyte. The cyclic performance of cells was also enhanced by pulverized electrolyte, which is also associated with improved contact stability at the cathode/electrolyte. These results show that the introduction of Li2MoO4-LiI coating and the use of pulverized sulfide electrolyte can exhibit a synergic effect of suppressed interfacial reaction by the coating layer and improved contact stability owing to the small particle size of electrolyte.

Characteristics of electrodeposited bismuth telluride thin films with different crystal growth by adjusting electrolyte temperature and concentration

  • Yamaguchi, Masaki;Yamamuro, Hiroki;Takashiri, Masayuki
    • Current Applied Physics
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    • v.18 no.12
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    • pp.1513-1522
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    • 2018
  • Bismuth telluride ($Bi_2Te_3$) thin films were prepared with various electrolyte temperatures ($10^{\circ}C-70^{\circ}C$) and concentrations [$Bi(NO_3)_3$ and $TeO_2:1.25-5.0mM$] in this study. The surface morphologies differed significantly between the experiments in which these two electrodeposition conditions were separately adjusted even though the applied current density was in the same range in both cases. At higher electrolyte temperatures, a dendrite crystal structure appeared on the film surface. However, the surface morphology did not change significantly as the electrolyte concentration increased. The dendrite crystal structure formation in the former case may have been caused by the diffusion lengths of the ions increasing with increasing electrolyte temperature. In such a state, the reactive points primarily occur at the tops of spiked areas, leading to dendrite crystal structure formation. In addition, the in-plane thermoelectric properties of $Bi_2Te_3$ thin films were measured at approximately 300 K. The power factor decreased drastically as the electrolyte temperature increased because of the decrease in electrical conductivity due to the dendrite crystal structure. However, the power factor did not strongly depend on the electrolyte concentration. The highest power factor [$1.08{\mu}W/(cm{\cdot}K^2$)] was obtained at 3.75 mM. Therefore, to produce electrodeposited $Bi_2Te_3$ films with improved thermoelectric performances and relatively high deposition rates, the electrolyte temperature should be relatively low ($30^{\circ}C$) and the electrolyte concentration should be set at 3.75 mM.

Effects of Electrolyte Concentration on Electrochemical Properties of an Iron Hexacyanoferrate Active Material (헥사시아노 철산철 활물질의 전기화학적 특성에 미치는 전해질 농도의 영향)

  • Yang, Eun-Ji;Lee, Sangyup;Nogales, Paul Maldonado;Jeong, Soon-Ki
    • Journal of Convergence for Information Technology
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    • v.11 no.2
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    • pp.117-123
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    • 2021
  • The effects of electrolyte concentration on the electrochemical properties of Fe4[Fe(CN6)]3(FeHCF) as a novel active material for the electrode of aqueous zinc-ion batteries was investigated. The electrochemical reactions and structural stability of the FeHCF electrode were significantly affected by the electrolyte concentration. In the electrolyte solutions of 1.0-7.0 mol dm-3, the charge-discharge capacities increased with increasing electrolyte concentration, however gradually decreased as the cycle progressed. On the other hand, in the 9.0 mol dm-3 electrolyte solution, the initial capacity was relatively small, however showed good cyclability. Additionally, the FeHCF electrode after five cycles in the former electrolyte solutions, had a change in crystal structure, whereas there was no change in the latter electrolyte solution. This suggests that the performance of the FeHCF electrode is greatly influenced by the hydration structure of zinc ions present in electrolyte solutions.