• Title/Summary/Keyword: $LiCoO_{2}$

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The Effect of NH3 Concentration during Co-precipitation of Precursors from Leachate of Lithium-ion Battery Positive Electrode Active Materials (리튬이차전지 양극활물질의 암모니아 침출액에서 공침법에 의한 활물질 전구체의 합성에 대한 암모니아 농도의 영향)

  • Park, Sanghyuk;Ku, Heesuk;Lee, Kyoung-Joon;Song, Jun Ho;Kim, Sookyung;Sohn, Jeongsoo;Kwon, Kyungjung
    • Resources Recycling
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    • v.24 no.6
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    • pp.9-16
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    • 2015
  • In a recycling scheme of spent lithium ion batteries, a co-precipitation process for the re-synthesis of precursor is essential after the leaching of lithium ion battery scraps. In this study, the effect of ammonia as impurity during the co-precipitation process was investigated in order to re-synthesize a precursor of Ni-rich cathode active material $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ (NCM 622). As ammonia concentration increases from 1 M (the optimum condition for synthesis of the precursors based on 2 M of metal salt solution) to 4 M, the composition of obtained precursors deviates from the designed composition, most notably for Ni. The Ni co-precipitation efficiency gradually decreases from 100% to 87% when the concentration of ammonia solution increases from 1 M to 4 M. Meanwhile, the morphological properties of the obtained precursors such as sphericity, homogeneity and size distribution of particles were also investigated.

Geochemical Dispersion and Enrichment of Fluvial Sediments Depending on the Particla Size Distribution (입도분포에 따른 하상퇴적물의 지구화학적 분산 및 부화)

  • 이현구
    • Economic and Environmental Geology
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    • v.32 no.3
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    • pp.247-260
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    • 1999
  • Geochermical characteristics of the fluvial sediments deprnding on particle size distribution size were investigated in the respect of majir, minor and rare eath element chemisitry. Ratios of $Al_{2}O_{3}/Na_{2}O$ and $K_{2}O/Na_{2}O$ of the sediments show the homogeneous valus, and partly positive correlation with $SiO_{2}/Al_{2}O_{3}$, respecively. Characteristics of minor element ratios (V/Ni, Cr/V, Ni/Co and Zr/Hf)are within the lower and narrow range. Thesesuggested that sediment sources may be acidic to intermediate granitic rock, and may be explained by simple weathering and sedimentation. With increasing SiO2 contents, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO and MgO decreased, but those of $K_{2}O$ and $Na_{2}O$ increased, Concentrations of Ba, Be, Cs, Cu, Li, Ni, Sr, V and Zr show comparatively normal negative and some positive trends. Compared with the mean composition of granite, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, MnO, CaO and MgO in the sediments of the study area were highly enriced. Among some minor and rare earth elements, concentrations of As, Cd, Cu, and V were enriched, but those of Be, Ce, Rb, Sc, Sr and Zn were depleted when compared with average composition of granite. By decreasing of particle size fractions, SiO2, Rb and Sr conterts decreased, but concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO, MgO, $TiO_{2}$, MgO, $P_{2}O_{5}$, Be, Cu, Hf, Pb, V and Zr increased. From the correlations between particle size fractions and element concenreations, some elements of $Fe_{2}O_{3}$, CaO, MgO, $P_{2}O_{5}$, Cu, Ni, Zn and Zr showed typical trends in the secondary contramination sediments. These trends are typically shown under 100 mesh fractions. It indicates that the fraction of minus 100 mesh is the optimum size fraction for geochemical and environmental survey.

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Development of New NLO Borate Crystal $>Gd_xY_{1-x}COB$

  • Sasaki, T.;Mori, Y.
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1998.06a
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    • pp.3-5
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    • 1998
  • The interest in the use of borate crystals in ultraviolet(UV) nonlinear optics(NLO) has increased because all solid-stste UV lasers obtained with NLO are in highly demand. Much effort has been spent on developing borates series, such as{{{{ { beta -BaB }_{2 } {O }_{4 }(BBO), {LiB }_{ 3}{O }_{5 }(LBO)}}}} and{{{{{ CsKiB}_{6 }{O }_{10 }(CLBO)}}}} in this decade. Recently another new borate crystals, {{{{{ YCa}_{4 }O({BO }_{3 })_{3}}}}} and{{{{{Gd }_{x }{Y }_{1-x }{Ca }_{4 }O({BO }_{ 3})({Gd }_{x }{Y }_{1-x }COB)}}}} have been developed by the present authors. Here, the growth and NLO properties of YCOB and {{{{ {Gd }_{ x} {Y }_{ 1-x} }}}}CO B crystal are reported and their properties discussed in relation to those of other nonlinear optical crystals, such as LBO.

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Order-disorder structural tailoring and its effects on the chemical stability of (Gd, Nd)2(Zr, Ce)2O7 pyrochlore ceramic for nuclear waste forms

  • Wang, Yan;Wang, Jin;Zhang, Xue;Li, Nan;Wang, Junxia;Liang, Xiaofeng
    • Nuclear Engineering and Technology
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    • v.54 no.7
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    • pp.2427-2434
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    • 2022
  • Series of unequal quantity Nd/Ce co-doped ceramic nuclear waste forms, (Gd, Nd)2(Zr, Ce)2O7, were prepared to tailor its ordered pyrochlore or disordered fluorite structure. The phase transition, microtopography, and elemental composition of the ceramic samples were systematically investigated, especially the effect of order-disorder structure on the chemical stability. It was confirmed that unequal quantity of Nd/Ce could synchronously replace the Gd/Zr-sites of Gd2Zr2O7. And the phase transition of order-disorder structure could be successfully tailored by regulating the average cationic radius ratio of (Gd, Nd)2(Zr, Ce)2O7 series. The elements of Gd, Nd, Zr, and Ce are uniformly distributed in the ordered or disordered structures. The MCC-1 leaching results showed that (Gd, Nd)2(Zr, Ce)2O7 pyrochlore ceramic nuclear waste forms had excellent chemical stability, whose elements' normalized leaching rates were as low as 10-4-10-7 g·m-2·d-1 after 7 days. In particular, the chemical stability of disordered structure was superior to that of ordered structure. It was proposed that the force constant and the closest packing were changed with the structure transformation resulting the chemical stability difference.

Studies of Flame Retardant Phospbazene Derivatives for Li- ion Batteries (리튬이차전지용 난영연성 전해질인 Phosphazene의 유도체들의 열적 안정성)

  • Kim, Ke-Tack;Ahn, Se-Young;Kim, Hyun-Soo;Kim, Young-Kyu;Kim, Byung-Hwa;Nam, Sang-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.308-308
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    • 2007
  • 리륨이차전지의 용량의 증가를 위한 연구에 많은 노력과 재원이 투자되고 잇는 반면에, 용량과 성능증가 추세가 주춤한 최근에는 전지의 안전성에 큰 관심이 집중되고 있다. 그 이유는 전지의 성능 못지않게 안전성에 대한 의구심이 꾸준히 제기되고 있고, 대용량 고출력전지의 대표적인 예이 자동차용 전지에는 안전성에 대한 보장이 선결되어야 하기 때문이다. 본 연구에서는 유기 전해액의 발화 및 폭발을 방지할수 있는 방법 중에서 첨가제에 의한 방법을 이용하여 그 첨가제의 전기화학적 특성 및 열적 안정성을 살펴보고 리튬이온전지에의 적용 가능성을 알아보았다. 특히 포스파젠 화합물들을 소량(1~5wt.%)첨가하여, 양극소재의 발열온도를 $60^{\circ}C$ 이상 지연시키고, 사이클 특성의 향상 및 용량의 증가도 실현함으로서 포스파젠 화합물의 유효성을 증명하였다. 아래의 Fig1은 Hexamethoxy cyclo tri-phosphazene(HMTP) 이라는 화합물의 난연성을 표기한 것인데, $270^{\circ}C$ 부근의 background peak가 $340^{\circ}C$까지 지연됨을 보여주고 있다.

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Effect of Nitrile-Functionalized Zwitterions on Electrochemical Properties of Electrolytes for Use in Lithium-ion Batteries

  • Lee, Bum-Jin;Kwak, Seung-Yeop
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.97.2-97.2
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    • 2012
  • This study examined the utility of two zwitterions, nitrile-functionalized zwitterions and a zwitterion without a nitrile group (MF-ZI), were used as additives along with 1 M $LiPF_6$ in ethylene carbonate (EC):diethylene carbonate (DEC) (3:7 V/V) (E-0) to form an electrolyte solution for use in lithium ion batteries comprising graphite and $LiCoO_2$ electrodes. The presence of NF-ZI (E-NF-ZI) in the electrolyte produced an ion conductivity comparable to that of E-0 and higher than that of an electrolyte containing MF-ZI (E-MF-ZI). Linear sweep voltammetry data revealed that the intensity of the E-NF-ZI reduction peak was lower than that of E-0. Furthermore, the successful formation of an SEI layer in the E-NF-ZI over graphite was confirmed by cyclic voltammetry data. These results were attributed to the adsorption of NF-ZI on the electrode surface, as verified by differential capacity measurements.

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The Electrochemical properties of Lithium ion Secondary Battery using Ag-deposited graphite anode (은 담지한 혹연을 부극 활물질로 이용한 Li ion 2차전지의 전기화학적 특성 연구)

  • 김상필;조정수;박정후;윤문수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.387-390
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    • 1998
  • New Ag-deposited graphite anodes were developed using wet chemical reduction methods for depositing Ag metal onto graphite particles. In this paper, we investigated X-ray diffraction pattern and charge-discharge behavior for Ag-deposited graphite anode. The Lithium ion cello using Ag-deposited graphite anode showed a high average discharge voltage of 3.6∼3.W and a excellent cycle ability than that of conventional graphite. Little capacity loss in this battery may be due to the highly durable Ag-deposited graphite anodes.

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Electrochemical Degradation of Textile Effluent Using PbO2 Electrode in Tube Electrolyzer

  • Chao Wang; Yongqiang Li;Junmin Wan;Yi Hu;Yi Huang
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.190-197
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    • 2024
  • A commercial PbO2 mesh cylinder electrode was utilized as the anode for the electrochemical degradation of the textile effluent after the biological treatment with the titanium cylinder as the cathode in a self-made tube electrolyzer. The electrochemical performances of the PbO2 electrode in tube electrolyzer under different initial pH, electrolyte flow rates, current densities and times of the electrochemical degradation were investigated. The experimental results illustrated that the PbO2 electrode can reduce the chemical oxygen demand (COD) of the textile effluent from 94.0 mg L-1 to 65.0 mg L-1 with the current efficiency of 88.3%, the energy consumption of 27.7 kWh kg-1 (per kilogram of degraded COD) and the carbon emissions of 18.0 kg CO2 kg-1 (per kilogram of degraded COD) under the optimal operating conditions. In addition, the COD of the textile effluent could be reduced from 94.0 mg L-1 to 22.0 mg L-1 after the fifth electrochemical degradation. Therefore, PbO2 mesh cylinder electrode in the tube cylinder was promising for the electrochemical degradation of the textile effluent.

A Study on the Dielectric and Piezoelectric properties of Low temperature sintering CW-PMN-PZT Ceramics according to the amount of $MnO_2$ addition ($MnO_2$ 첨가에 따른 저온소결 PCW-PMN-PZT 세라믹스의 유전 및 압전특성에 관한 연구)

  • Chung, Kwang-Hyun;Lee, Duck-Chool;Yoo, Ju-Hyun;Park, Chang-Yub;Jeong, Yeong-Ho
    • Proceedings of the KIEE Conference
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    • 2004.11a
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    • pp.82-85
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    • 2004
  • In this study, in order to increase piezoelectric properties of the low temperature sintering ceramics for multilayer piezoelectric transformer, PCW-PMN-PZT ceramics added with $Li_2CO_3$, $Bi_2O_3$ and CuO as sintering aids were manufactured according to the amount of $MnO_2$ addition, and their microstructural, dielectric and piezoelectric properties were investigated. When the sintering aids was added, specimens could be sintered at $950^{\circ}C$. However, sintering aids added specimens showed lower piezoelectric properties than those of non-added specimens. $0.1wt%MnO_2$ added specimen at $950^{\circ}C$ showed ${\varepsilon}_r$, of 1503, $k_p$ of 0.57 and $Q_m$ of 1502 were shown, respectively, and showed optimum properties for multilayer piezoelectric transformer.

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Effect of Poling Filed on The Piezoelectric and Dielectric Characteristics of $(K_{0.5}Na_{0.5})NbO_3$ Ceramics (분극전계가 $(K_{0.5}Na_{0.5})NbO_3$세라믹스의 압전 및 유전특성에 미치는 영향)

  • Lee, Il-Ha;Yoo, Ju-Hyun;Yoon, Hyun-Sang;Paik, Dong-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.56-56
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    • 2008
  • 최근, 비납 또는 납의 함량을 줄인 압전 세라믹에 대한 관심이 증가하고 있고, 그에 따른 여러 연구가 활발히 이루어지고 있다. 납을 포함하는 세라믹은 높은 소성온도에서 납의 휘발로 인한 특성저하와 환경오염 등이 문제가 된다는 것을 우리는 익히 알고 있다. 그렇기 때문에 PZT계 세라믹스를 대체할 우수한 특성을 가지는 새로운 비납 세리믹스의 조성개발이 시급하다. 비납계 세라믹스 중에서 NKN계를 바탕으로 하는 세라믹스는 가장 기대되는 재료이다. 일반적인 소성에서 순수한 NKN 세라믹은 가장 높은 압전 $d_{33}$상수가 100 pC/N이 넘지 않는다. 그런데 페로브스카이트 구조로된 NKN세라믹스의 A-site에 $Li^{1+}$이온을 치환하면 압전 특성을 향상시킬 수 있다. 그리고, 압전세라믹에서 분극처리는 필수적인데 분극처리는 압전성을 부여할 뿐 아니라 다른 물성도 변화시킴은 잘 알려져 있다. 그러므로 그에 대한 연구 또한 중요한 의미를 갖는다. 따라서 이번 연구에서는 NKN세라믹스에 $Li_2CO_3$를 소결조제로 첨가하여 시편을 제작하였고, 제작된 시편의 특성을 분극전계에 따라 조사하였다.

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