• 제목/요약/키워드: Discharge Capacities

검색결과 120건 처리시간 0.028초

Mg와 Zn의 복합치환에 따른 LiMn2-yMyO4 정극 활물질의 결정 구조 및 전기화학적 특성 (Crystal Structure and Electrochemical Properties of LiMn2-yMyO4 Cathode Material by Complex Substitution of Mg and Zn)

  • 정인성;정해덕;구할본
    • 한국전기전자재료학회논문지
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    • 제15권4호
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    • pp.361-366
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    • 2002
  • Spinel $LiMn_{2-y}M_yO_4$ and $LiMn_{2-y}M_yO_4$ (M=Mg, Zn) powders were synthesized by solid-state method at $800^{\circ}C$ for 37h. Crystal structure and electrochemical properties were analyzed by X-ray diffraction, charge-discharge test, cyclic voltammetry and ac impedance to $LiMn_{2-y}M_yO_4$. All cathode material showed spinel structure in X-ray diffraction. Ununiform distortion which calculated by (111) face and (222) face was almost constant in spite of the change of the kind and the substituting ratio of the metal cation in $LiMn_{2-y}M_yO_4$ (M=Mg, Zn). $LiMn_{1.9}Mg_{0.05}Zn_{0.05}O_4/Li$ 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 $LiMn_{2-y}M_yO_4/Li$ cells showed the similar resistance of about 65~110$\Omega$ before cycling.

흑연 코팅 집전체를 이용한 Lithium Terephthalate 기반 리튬-유기 이차전지의 전기화학적 특성 개선 (Improving the Electrochemical Properties of Lithium Terephthalate-based Lithium-Organic Battery with A Graphite Coated Current Collector)

  • 권오현;김종빈;김재광
    • 전기화학회지
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    • 제22권3호
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    • pp.122-127
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    • 2019
  • 유기이차전지가 가지고 있는 전극 내 낮은 접합력과 높은 계면저항의 단점을 해결하기 위하여 본 연구에서는 흑연 코팅 처리된 집전체를 사용하여 lithium terephthalate (LTA)전지의 전기화학적 특성 변화를 분석하였다. LTA 음극 활물질은 산의 이온 치환반응에 의하여 불순물 없이 합성되어 졌다. 막대 형태의 LTA 활물질로 제작된 전극과 흑연 코팅 처리된 집전체와의 접합특성은 SEM 단면과 EIS를 통하여 확인하였다. 흑연 코팅된 집전체를 사용한 LTA전지의 계면저항은 현저히 감소되었다. 순수한 금속 집전체 LTA 전지와 흑연 코팅 처리된 금속 기판 LTA 전지는 0.1C의 두 번째 사이클에서 107.6 mAh/g와 148.8 mAh/g의 방전 용량을 보인다. 흑연 코팅된 집전체를 사용한 LTA 전지는 순수한 LTA 전지에 비하여 우수한 수명 특성과 높은 방전 용량, 그리고 높은 고율 특성을 가진다.

막여과 정수장에서의 배출수처리시설 설계인자 평가 (Evaluation of Design Parameter on Residuals Treatment Facilities in Membrane Water Treatment Plants)

  • 문용택;서인석;김홍석;박노석;안효원
    • 상하수도학회지
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    • 제20권1호
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    • pp.138-146
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    • 2006
  • The characteristics of backwash and concentrate discharges depend upon the quality of the water being treated and the net recovery of the membrane system. This paper is to indicate a design methods on the capacities of residuals treatment facilities in membrane processes for drinking water. We operated a demonstration membrane plant with a recovery rate of 90% for designing G-water treatment plant. We investigated on design parameter (optimum coagulant dosage and surface loading rate etc.) to design efficiently the residuals treatment facilities. The settling test was conducted with 1m columns dosing PACl to kaolin and membrane residuals under the experimental condition that discharge permit was under a 60mg/L. When the quantity of membrane residuals was $1,575m^3/day$, the estimated results for 1st thickener demonstrated the surface loading rate of 14.4m/day, detention time of 5.83hr, available depth of 3.5m.

Pyro-synthesis of Na2FeP2O7 Nano-plates as Cathode for Sodium-ion Batteries with Long Cycle Stability

  • Song, Jinju;Yang, Juhyun;Alfaruqi, Muhammad Hilmy;Park, Wangeun;Park, Sohyun;Kim, Sungjin;Jo, Jeonggeun;Kim, Jaekook
    • 한국세라믹학회지
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    • 제53권4호
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    • pp.406-410
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    • 2016
  • Carbon-coated sodium iron pyrophosphate ($Na_2FeP_2O_7$) was prepared by a simple and low-cost pyro-synthesis route for further use as the cathode for Na-ion batteries. The X-ray diffraction (XRD) pattern of the sample annealed at $650^{\circ}C$ confirmed the pure triclinic phase of $Na_2FeP_2O_7$. Electron microscopy studies revealed a cross linked plate shape morphology of the $Na_2FeP_2O_7$ sample. When tested for application in Na-ion battery, the $Na_2FeP_2O_7$ cathode showed two redox pairs in the potential window of 2.0-4.0 V. The cathode registered initial discharge and charge capacities of 80.85 and 90 mAh/g, respectively, with good cycling performance.

고분자캐패시터에 대한 충방전 조건에서의 온도에 따른 정전용량감소 특성 연구 (Study on Capacitance Decreasing Characteristics of Polymer Capacitor Depending on Temperature with Charging-Discharging Condition)

  • 정의효;임홍우;형재필;고민지;정창욱;조정하;장중순
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제17권1호
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    • pp.66-71
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    • 2017
  • Purpose: Polymer capacitors are known to have very high reliability as compared with liquid electrolytic capacitors, but their capacity has been reported to decrease in charge and discharge at low temperature. The purpose of this study to clarify these characteristics. Methods: In order to clarify these characteristics, charging-discharging tests were carried out for 200 hours with three different capacities and at 5 different temperature from $5^{\circ}C$ to $100^{\circ}C$. Results: As a result of the test, it was confirmed that the capacity of the polymer capacitor was decreased with higher capacity and lower temperature. Conclusion: Such a failure phenomenon was caused by the shrinkage and expansion characteristics of the polymer used therein, it is presumed that this failure phenomenon is due to the complex pore structure made by etching.

하이브리드 (활성탄소+LiCoO2) 전극의 전기화학적 특성 (Electrochemical Performance of Hybrid (Activated Carbon+LiCoO2) Electrode)

  • 김익준;전민제;양선혜;김현수;문성인;오대희
    • 한국전기전자재료학회논문지
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    • 제19권9호
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    • pp.849-854
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    • 2006
  • In this study, the hybrid electrodes, composed of the activated carbon powders and $LiCoO_{2}$ powders, were prepared as a cathode for the high-capacitance type hybrid capacitor, and the electrochemical properties of the hybrid electrodes were examined in terms of the weight composition and the milling time of $LiCoO_{2}$ powders. The specific volumetric capacities were increased with increasing of the composition of $LiCoO_{2}$ powders in the hybrid electrodes. On the other hand the coin cell capacitors, using the hybrid electrodes with $LiCoO_{2}$ poweders milled for 200 h, have exhibited the lower internal resistivities and the better capacity retention after 100 charge-discharge cycle than those of the coin cell capacitors using the hybrid electrodes with raw $LiCoO_{2}$ powders.

The Synthesis of Na0.6Li0.6[Mn0.72Ni0.18Co0.10]O2 and its Electrochemical Performance as Cathode Materials for Li ion Batteries

  • Choi, Mansoo;Jo, In-Ho;Lee, Sang-Hun;Jung, Yang-Il;Moon, Jei-Kwon;Choi, Wang-Kyu
    • Journal of Electrochemical Science and Technology
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    • 제7권4호
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    • pp.245-250
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    • 2016
  • The layered $Na_{0.6}Li_{0.6}[Mn_{0.72}Ni_{0.18}Co_{0.10}]O_2$ composite with well crystalized and high specific capacity is prepared by molten-salt method and using the substitution of Na for Li-ion battery. The effects of annealing temperature, time, Na contents, and electrochemical performance are investigated. In XRD analysis, the substitution of Na-ion resulted in the P2-$Na_{2/3}MO_2$ structure ($Na_{0.70}MO_{2.05}$), which co-exists in the $Na_{0.6}Li_{0.6}[Mn_{0.72}Ni_{0.18}Co_{0.10}]O_2$ composites. The discharge capacities of cathode materials exhibited $284mAhg^{-1}$ with higher initial coulombic efficiency.

The Effects of LaF3 Coating on the Electrochemical Property of Li[Ni0.3Co0.4Mn0.3]O2 Cathode Material

  • Yun, Su-Hyun;Kim, Seuk-Buom;Park, Yong-Joon
    • Bulletin of the Korean Chemical Society
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    • 제30권11호
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    • pp.2584-2588
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    • 2009
  • The effect of $LaF_3$ coating on the structural and electrochemical properties of $Li[Ni_{0.3}Co_{0.4}Mn_{0.3}]O_{2}$ cathodes was investigated using XRD, SEM, TEM, and a cycler. The coating layer consisted of nano-sized particles attached nonuniformly to the surface of pristine powder. Despite the surface coating treatment, phase difference by $LaF_3$ coating was not detected. The discharge capacities of coated electrodes were a little lower than that of pristine sample at a 1 C rate. However, as the C rate increases, the capacity retention of the coated sample becomes obviously superior to that of the pristine sample. The cyclic performances of the electrodes in the voltage range of 4.8 $\sim$ 3.0 V were also improved by the surface coating. Such enhancement is attributed to the presence of the $LaF_3$ coating layer, which effectively suppressd the reaction between electrodes and electrolytes on the surface of the $Li[Ni_{0.3}Co_{0.4}Mn_{0.3}]O_{2}$ electrode.

Preparation and Characterization of Pitch/Cokes Composite Anode Material for High Power Lithium Secondary Battery

  • Yu, Lan;Kim, Ki-Jung;Park, Dae-Yong;Kim, Myung-Soo;Kim, Kab-Il;Lim, Yun-Soo
    • Carbon letters
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    • 제9권3호
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    • pp.210-217
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    • 2008
  • Petroleum pitch and coke with wet mixture method or with dry mixture method were investigated to develop the composite anodic carbon material of high power lithium ion battery. Cokes coated with pitch were obtained by the heat treatment of mixture of cokes and pitch with different weight ratios at $800{\sim}1200^{\circ}C$. The charge and discharge characteristic of the consequent composite anodic carbon material assembled in batteries was tested. Cokes with wet mixture method have a smooth surface and their capacity changed little with changing temperature and content as compared to the cokes with dry mixture method. Although the reversible capacities showed different values by the anode manufacturing method, the composite anode with the mixture of 20 wt% of petroleum pitch and 80 wt% of coke showed the higher power capability and initial efficiency than the pitch based anode. However, the reversible capacity of the composite anode showed the reduced value as compared with the pitch based anode.

다층 산화주석(SnO)의 합성 및 열처리를 통한 리튬이온 이차전지 음극 소재의 성능 향상 (Synthesis of the Multi-layered SnO Nanoparticles and Enhanced Performance of Lithium-Ion Batteries by Heat treatment)

  • 이소이;명윤;이규태;최재원
    • 한국분말재료학회지
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    • 제28권6호
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    • pp.455-461
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    • 2021
  • In this study, multilayered SnO nanoparticles are prepared using oleylamine as a surfactant at 165℃. The physical and chemical properties of the multilayered SnO nanoparticles are determined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Interestingly, when the multilayered SnO nanoparticles are heated at 400℃ under argon for 2 h, they become more efficient anode materials, maintaining their morphology. Heat treatment of the multilayered SnO nanoparticles results in enhanced discharge capacities of up to 584 mAh/g in 70 cycles and cycle stability. These materials exhibit better coulombic efficiencies. Therefore, we believe that the heat treatment of multilayered SnO nanoparticles is a suitable approach to enable their application as anode materials for lithium-ion batteries.