• Title/Summary/Keyword: LI4

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The correlation of the eletrochemical properties for $Li[Li_yMn_{2-y}]O_4$ cathode materials ($Li[Li_yMn_{2-y}]O_4$ 정극 활물질에 대한 전기화학적 특성의 상호관계)

  • Jeong, In-Seong;Kim, Min-Sung;Gu, Hal-Bon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.269-272
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    • 2000
  • Spinel $LiMn_2O_4$ samples are prepared by heating a $LiOH{\cdot}H_2O/MnO_2$ mixture in air at $800^{\circ}C$ for 36h, and their structure and electrochemical performance are studied by using X-ray diffraction, Cyclic Voltammetry, AC Impedance, and Charge-discharge measurements. It was found that the electrochemical properties of the $LiMn_2O_4$ samples are very sensitive to substituted volume of lithium. Initial impedances of all cathode was similar. Initial resistance was $60{\sim}70{\Omega}$. Reaction peak of Cyclic voltammetry was weak by increase of substituted volume of lithium. $Li[Li_{0.08}Mn_{1.92}]O_4$ and $Li[Li_{0.1}Mn_{1.9}]O_4$ cathode materials showed the charge and discharge capacity of about 125mAh/g at first cycle, and about 95mAh/g after 70th cycle. It showed excellent property in sample revealed good structure and other electrochemical property.

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Li+ and Li+I-Li+ ions Solvated by 1,4-dioxane: An ion Mobility Spectrometry-Mass Spectrometry Study

  • Choi, Yunseop;Ji, Inyong;Seo, Jongcheol
    • Mass Spectrometry Letters
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    • v.12 no.4
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    • pp.152-158
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    • 2021
  • Electrospray ionization (ESI) and ion mobility spectrometry-mass spectrometry (IMS-MS) were employed to investigate the solvated structures of ionic species in the lithium iodide electrolyte solution in the gas phase. The Li+I-Li+ triple ion and single standalone Li+ ions solvated by 1,4-dioxane were successfully generated and observed by ESI-MS under the influence of dioxane vapor at the inlet region. Under the present experimental condition, (1,4-dioxane)m·Li+ complex ions (m = 1, 2, and 3) and a (1,4-dioxane)·Li+I-Li+ complex ion were observed, which were further examined by IMS to investigate their structures. The presence of multiple structural isomers was confirmed, which accounts for the endothermic conformational transition of 1,4-dioxane from a chair to a boat to achieve bidentate O-donor binding to Li+ and Li+I-Li+. Further structural details critical for the ion-solvent interactions were also examined and discussed with the help of density functional theory calculations.

Electrical Characteristics of Li(Mn$_{1-}$$\delta$Nb$\delta$)$_2$O$_4$ Cathode Materials for Li-Ion Secondary Batteries (리튬 이온 이차전지 Cathode용 Li(Mn$_{1-}$$\delta$Nb$\delta$)$_2$O$_4$의 전기적 특성)

  • 오용주;유광수
    • Journal of the Korean Ceramic Society
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    • v.35 no.9
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    • pp.995-1001
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    • 1998
  • As a basic study for cathode materials of {{{{ { {LiMn }_{2 }O }_{4 } }}-based lithium-ion secondary batteries Li({{{{ { { { {Mn }_{1-$\delta$ }Nb }_{$\delta$} )}_{2 }O }_{4 } }} ($\delta$=0.05, 0.1, 0.2) materials which Nb is substituted for Mn were synthesized by the solid state reaction at 80$0^{\circ}C$ and 110$0^{\circ}C$ respectively. The second phase {{{{ { LiNbO}_{3 } }} appeared above $\delta$=0.1 As the result of im-pedance analysis as the amount of substituted Nb increased the resistivity of grain boundary increased greatly. Compared to undoped-{{{{ { {LiMn }_{2 }O }_{4 } }} the electrical conductivity of Li({{{{ { { { {Mn }_{1-$\delta$ }Nb }_{$\delta$} )}_{2 }O }_{4 } }} decreased slightly but is charging capacity and potential plateau increased.

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Conductivity properties of ion conducting polymer electrolyte based on poly(ethylene oxide) (이온전도성 poly(ethylene oxide)고분자전해질의 전도특성)

  • 김종욱;문성인;진봉수;구할본;윤문수
    • Electrical & Electronic Materials
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    • v.8 no.4
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    • pp.487-494
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    • 1995
  • The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. We investigated the effects of lithium salts, plasticizer addition, temperature dependence of conductivity and electrochemical stability window of polyethylene oxide(PEO) electrolytes. PEO electrolyte completed with LiCIO$\_$4/ shows the better conductivity than the others. PEO-LiCIO$\_$4/ electrolyte, when EO/Li$\^$+/ ratio is 8, showed adequate conductivity around room temperature. By adding propylene carbonate and ethylene carbonate to PEO-LiCIO$\_$4/ electrolyte, its conductivity was higher than that of PEO-LiCIO$\_$4/ without those. Also PEO$\_$8/LiCIO$\_$4/ electrolyte remains stable up to 4.5V vs. Li/Li.

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Charge/discharge Properties of $LiMn_2O_4$ Composite Cathode for All-solid state Rechargeable Batteris (리튬 고체전지용 $LiMn_2O_4$ Composite Cathode의 충방전 특성)

  • Kim, Jong-Uk;Park, Gye-Choon;Gu, Hal-Bon
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1511-1513
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    • 1998
  • The purpose of this study is to research and develop PEO/PVDF electrolytes and $LiMn_2O_4$ composite cathode for all-solid state lithium rechargeable battery. We investigated AC impedance response and charge/discharge cycling of $LiMn_2O_4$/SPE/Li cells. The cell resistance was decreased so much initial charge process from 0% SOC to 100% SOC. The radius of semicircle of $LiMn_2O_4$/SPE/Li cell was so much from initial state to 20th cycling. The discharge capacity of the $LiMn_2O_4$ composite cathode was 144mAh/g based on $LiMn_2O_4$.

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Electrochemical Properties of Spinel $LiMn_2O_4$Synthesized at Various Sintering Condition (열처리 조건에 따른 스피넬 $LiMn_2O_4$의 전기 화학적 특성)

  • 한태희;박종광;한병성
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.12 no.1
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    • pp.50-55
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    • 1999
  • We have investigated the $LiMn_2O_4$system as an cathode material for lithium rechargeable batteries. $LiMn_2O_4$spinel oxides have been synthesized by a solid state methode. We varied sintering time at a fixed sintering temperature of 75$0^{\circ}C$. In order to investigate the electrochemical properties of prepared $LiMn_2O_4$we assembled three-electrode cells using the working electrode as active material and Li metal as the counter and reference electrodes. The electrolyte was 1 M LiPE$_{6}$-EC:DEC(1:1 by volume). The particle size of sample synthesized at 75$0^{\circ}C$ ranged about 60$\mu m$. The discharge capacity of a cell involving spinel $LiMn_2O_4$ increased with increasing sintering time.e.

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The effect of acupuncture treated by tonification and sedation manipulation at LI4 and KI7 on lacking of sweating in cold environment(I) (합곡(合谷) 복류(復溜) 보사(補瀉) 시술(施術)이 소한(少汗)에 미치는 영향(影響)(I))

  • Choi, Chan-Hun;Youn, Dae-Hwan;Kim, Young-Sun;Song, Min-Sun;Na, Chang-Su
    • Korean Journal of Acupuncture
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    • v.26 no.4
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    • pp.23-38
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    • 2009
  • Objectives : The purpose of this study was to identify the effect of the tonification & sedation manipulation for LI4 and KI7 on lacking of sweating in cold environment. Methods: The participants were divided into 3 groups as intact group without acupuncture, acupuncture group inserting and twisting with LI4 tonificaton and KI7 sedation method(LI4-tonify KI7-purge) and acupuncture group inserting and twisting with LI4 sedation and KI7 tonificaton method(LI4-purge KI7-tonify). We obtained baseline data at cold condition with the temperature $14{\pm}1^{\circ}C$. After making the participant staying in cold condition for 10 minute, we measured sweating rate in skin surface, body temperature, oxygen saturation, pulse rate, systolic blood pressure, diastolic blood pressure, deoxy-Hb and oxy-Hb in subcutaneous. Results : After acupuncture in cold environment, the sweating rate in skin surface significantly decreased in KI7-purge LI4-tonify group comparing the intact groups. The body temperature significantly increased in LI4-tonify KI7-purge and LI4-purge KI7-tonify groups comparing the intact group. The oxygen saturation significantly increased in LI4-tonify KI7-purge group comparing the intact group. Conclusions : These findings indicated that LI4 tonificaton and KI7 sedation method(LI4-tonify KI7-purge) could be effective for production of sweating in cold condition.

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Electrochemical Characteristics of Carbon-coated LiFePO4 as a Cathode Material for Lithium Ion Secondary Batteries

  • Shin, Ho-Chul;Lee, Byung-Jo;Cho, Won-Il;Cho, Byung-Won;Jang, Ho
    • Journal of the Korean Electrochemical Society
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    • v.8 no.4
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    • pp.168-171
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    • 2005
  • The electrochemical properties of $LiFePO_4$ as a cathode for Li-ion batteries were improved by incorporating conductive carbon into the $LiFePO_4$. X-ray diffraction analysis and SEM observations revealed that the carbon-coated $LiFePO_4$ consisted of fine single crystalline particles, which were smaller than the bare $LiFePO_4$. The electrochemical performance of the carbon-coated $LiFePO_4$ was tested under various conditions. The carbon-coated $LiFePO_4$ showed much better performance in terms of the discharge capacity and cycling stability than the bare $LiFePO_4$. The improved electrochemical performances were found to be attributed to the reduced particle size and enhanced electrical conductivity of the $LiFePO_4$ by the carbon.

Electrochemical Properties of Binary Electrolytes for Lithium-sulfur Batteries

  • Kim, Hyung-Sun;Jeong, Chang-Sik
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3682-3686
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    • 2011
  • The electrochemical properties of lithium-sulfur batteries with binary electrolytes based on DME and DOL, TEGDME and DOL mixed solvent containing $LiClO_4$, LiTFSI, and LiTF salts were investigated. The ionic conductivity of 1M LiTFSI and $LiClO_4$ electrolytes based on TEGDME and DOL increased as the volume ratio of DOL solvent increased, because DOL effectively reduces the viscosity of the above electrolytes medium under the same salts concentration. The first discharge capacity of lithium-sulfur batteries in the DME and DOL-based electrolyte followed this order: LiTFSI (1,000 mAh/g) > LiTF (850 mAh/g) > $LiClO_4$ (750 mAh/g). In case of the electrolyte based on TEGDME and DOL, the first discharge capacity of batteries followed this order: $LiClO_4$ (1,030 mAh/g) > LiTF (770 mAh/g) > LiTFSI (750 mAh/g). The cyclic efficiency of lithium-sulfur batteries at 1M $LiClO_4$ electrolytes is higher than that of batteries at other lithium salts-based electrolytes. Lithium-sulfur battery showed discharge capacity of 550 mAh/g until 20 cycles at all electrolytes based on DME and DOL solvent. By contrast, the discharge capacity of batteries was about 450 mAh/g at 1M LiTFSI and LiTF electrolytes based on TEGDME and DOL solvent after 20 cycles.

Effect of Interaction between Lithium Ions on Lithium Transport : Analysis of Potentiostatic Current Transient Measured on $Li_{1+\delta}[Ti_{5/3}/Li_{1/3}]O_4$ Film Electrode ($Li_{1+\delta}[Ti_{5/3}/Li_{1/3}]O_4$ 박막 전극내의 리튬 이동에 미치는 리튬 이온들간의 상호작용의 영향 : $Li_{1+\delta}[Ti_{5/3}/Li_{1/3}]O_4$ 박막 전극의 정전압 전류추이곡선의 해석)

  • 정규남;변수일;김성우
    • 한국전기화학회:학술대회논문집
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    • 2001.10a
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    • pp.41-41
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    • 2001
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