• 제목/요약/키워드: Li-gu

검색결과 394건 처리시간 0.032초

Electrochemical Characteristics of $LiFePO_4$ with Conductivity Materials for Lithium Polymer Batteries

  • Jin, En Mei;Wang, Jiao;Zhao, Xing Guan;Park, Kyung-Hee;Gu, Hal-Bon;Park, Bok-Kee
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.132-132
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    • 2009
  • Phospho-olivine $LiFePO_4$ cathode materials were prepared by hydrothermal reaction. In this study, Multi-walled carbon nanotube (MWCNT) and Carbon black was added to enhance the electrical conductivity of $LiFePO_4$. $LiFePO_4$, $LiFePO_4$-MWCNT and $LiFePO_4$-C particles were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) transmission electron microscope (TEM). $LiFePO_4/SPE/Li$, $LiFePO_4$-MWCMT/SPE/Li and $LiFePO_4$-C/SPE/Li cells were characterized electrochemically by charge/discharge experiments at a constant current density of $0.1mA\;cm^{-2}$ in a range between 2.5 and 4.3 V vs. $Li/Li^+$ and cyclic voltammetry (CV).

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Synthesis LiFePO4- poly(sodium 4-styrenesulfonate) composite cathode material for rechargeable lithium battery by hydrothermal method

  • Hiep, Nguyen Van;Wang, Wan Lin;Jin, En Mei;Gu, Hal-Bon
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 추계학술대회 초록집
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    • pp.137.2-137.2
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    • 2011
  • Poly (sodium 4-styrenesulfonate) (PSS) is ionomer based on polystyrene that is electrical conductivity and isoviscosity. LiFePO4 has been a promising electrode material however its poor conductivity limits practical application. To enhance the electronic conductivity of LiFePO4, in this study we prepared LiFePO4- PSS composite by the hydrothermal method. LiFePO4 was heated at $170^{\circ}C$ for 12h and then different wt% PSS (0%, 2.91%, 4.75%, 7.36%, 10%) are added to LiFePO4 and milled at 300rpm for 10h. And then the obtained powders were subsequently heated at $500^{\circ}C$ for 1h under argon flow. The cathode electrode were made from mixtures of LiFePO4-PSS: SP-270- PVDF in a weighting ratio 75%: 25%:5%. The electrochemical properties of LiFePO4- PSS/Li batteries were analyzed by cyclic voltammetry and charge/discharge tests. LiFePO4-C/Li battery with 4.75 wt% PSS displays discharge capacity of 128 mAh g-1 at room temperature that is considerably higher than pure LiFePO4/Li battery ( 113.48 mAhg-1).

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리튬 폴리머 전지용 $LiFe_xMn_{1-x}PO_4$ 정극활물질의 전기화학적 특성 (The electrochemical properties of $LiFe_xMn_{1-x}PO_4$ cathode materials for lithium polymer batteries)

  • 전대규;구할본
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.424-425
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    • 2005
  • The purpose of this study is to research and develop $LiFe_xMn_{1-x}PO_4$ cathode for lithium polymer batteries. $LiFe_xMn_{1-x}PO_4$ cathode active materials were prepared using a solid-state reaction by adding carbon black to the synthetic precursors. We investigated cyclic voltammetry and charge/discharge cycling of $LiFe_xMn_{1-x}PO_4$/SPE/Li cells. The discharge capacity of $LiFe_{0.5}Mn_{0.5}PO_4$ was l26mAh/g and 110mAh/g at 1st and 10th cycle.

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홍화약침(紅花藥鍼)을 사용한 요골두 아탈구 환자 치험 1례 (One Case of Subluxation of the Head of the Radius treated with Carthami Flos Herbal-Acupuncture(CF))

  • 이윤경;임성철;정태영;서정철;한상원
    • Journal of Acupuncture Research
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    • 제21권6호
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    • pp.291-298
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    • 2004
  • Objective : This study was designed to investigate the effect of Carthami Flos Herbal-Acupuncture(CF) on Subluxation of the Head of the Radius. Methods : CF was administered one time per 2days. The following points were selected : TE10(天井), LI11(曲池), LI10(手三里). After CF administration conventional body-acupuncture was performed at the same points. We evaluated the patient through Visual Analogue Scale(VAS) and Elbow Range of Motion(ROM). Results : After 6 times of treatment, the patient showed that clinical symptoms was disappeared, VAS changed from 10 to 1 and there was no limitation of ROM. Conclusions : According to the results, CF and early Exercising may have rapid effects on the Subluxation of the Head of the Radius. But further studies are required to prove the effect of CF on Subluxation of the Head of the Radius.

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리튬폴리머전지용 정극활물질 LiFePO4의 전기화학적 특성 (Electrochemical Properties of LiFePO4 Cathode Materials for Lithium Polymer Batteries)

  • 공명철;김현수;구할본
    • 한국전기전자재료학회논문지
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    • 제19권6호
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    • pp.519-523
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    • 2006
  • $LiFePO_4$ has been received attention as a potential cathode material for the lithium secondary batteries. In our study, $LiFePO_4$ cathode active materials were synthesized by a solid-state reaction. It was modified by coating $TiO_2$ and carbon in order to enhance cyclic performance and electronic conductivity. $TiO_2$ and carbon coatings on $LiFePO_4$ materials enhanced the electronic conductivity and its charge/discharge capacity. For lithium polymer battery applications, $LiFePO_4$/solid polymer electrolyte (SPE)/Li and $LiFePO_{4}-TiO_{2}/SPE/Li$ cells were characterized by a cyclic voltammetry and charge/discharge cycling. The electrode with $LiFePO_{4}-carbon-TiO_{2}$ in PVDF-PC-EC-$LiClO_{4}$ electrolyte showed promising capacity of above 100 mAh/g at 1C rate.

Mg와 Zn이 치환된 $LiMn_2O_4$ 정극 활물질의 제조 및 특성 분석 (Preparation and Analysis of$LiMn_2O_4$ Cathode Material substituted Mg and Zn)

  • 정인성;구할본;한규승
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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    • pp.707-710
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    • 2002
  • Spinel $LiMn_2O_4$ and $LiMn_{1.9}Mg_{0.05}Zn_{0.05}O_4$ powders were synthesized by solid-state method at $800^{\circ}C$ for 36h. Crystal structure and electrochemical properties were analyzed by X-ray diffraction, charge-discharge test, cyclic voltammetry and ac impedance to $LiMn_2O_4$ and $LiMn_{1.9}Mg_{0.05}Zn_{0.05}O_4/Li$. All cathode material showed spinel structure in X-ray diffraction. $LiMn_{1.9}Mg_{0.05}Zn_{0.05}O_4/Li$ cell substituted $Mg^{2+}$ and $Zn^{2+}$ showed excellent discharge capacities than other cells, which it presented about 120mAh/g at the 1st cycle and about 73mAh/g at the 250th cycle, respectively. AC impedance of $LiMn_{1.9}Mg_{0.05}Zn_{0.05}O_4/Li$ cells showed the similar resistance of about $65{\sim}110{\Omega}$ before cycling.

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

  • 정인성;김민성;구할본
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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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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