• KIEE International Transactions on Electrophysics and Applications
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• 제5C권3호
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• pp.119-123
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• 2005

Lithium titanium oxide as anode material for energy storage prepared by novel synthesis method. Li$_{4}$Ti$_{5}$O$_{12}$ based spinel-framework structures are of great interest material for lithium-ion batteries. We describe here Li$_{4}$Ti$_{5}$O$_{12}$ a zero-strain insertion material was prepared by novel sol-gel method and by high energy ball milling (HEBM) of precursor to from nanocrystalline phases. According to the X-ray diffraction and scanning electron microscopy analysis, uniformly distributed Li$_{4}$ Ti$_{5}$O$_{12}$ particles with grain sizes of 100nm were synthesized. Lithium cells, consisting of Li$_{4}$ Ti$_{5}$O$_{12}$ anode and lithium cathode showed the 173 mAh/g in the range of 1.0 $\~$ 3.0 V. Furthermore, the crystalline structure of Li$_{4}$ Ti$_{5}$O$_{12}$ didn't transform during the lithium intercalation and deintercalation process.

• Corrosion Science and Technology
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• 제21권4호
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• pp.250-257
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• 2022

Transition metal sulfide materials have emerged as a new anode material for Li secondary batteries owing to their high capacity and rate capability facilitated by fast Li-ion transport through the layered structure. Among these materials, niobium disulfide (NbS₂) has attracted much attention with its high electrical conductivity and high theoretical capacity (683 mAh g^-1). In this study, we propose a facile synthesis of Fe_xNbS₂/C composite via simple ball milling and heat treatment. The starting materials of FeS and Nb were reacted in the first milling step and transformed into an Fe-Nb-S composite. In the second milling step, activated carbon was incorporated and the sulfide was crystallized into Fe_xNbS₂ by heat treatment. The prepared materials were characterized by X-ray diffraction, electron spectroscopies, and X-ray photoelectron spectroscopy. The electrochemical test results reveal that the synthesized Fe_xNbS₂/C composite electrode demonstrates a high reversible capacity of more than 600 mAh g^-1, stable cycling stability, and excellent rate performance for Li-ion battery anodes.

• 한국인터넷방송통신학회논문지
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• 제24권2호
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• pp.127-132
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• 2024

최근 이차전지는 다양한 산업 분야에서 사용되고 있다. 특히 소형 및 경량의 특성으로 스마트폰, 노트북, 태블릿 등 다양한 휴대용 전자기기에서 높은 에너지 밀도와 충·방전 효율을 토대로 전기자동차와 에너지저장시스템(Energy Storage System, ESS)의 핵심 부품으로 사용되고 있다. 하지만 이차전지의 과도한 충·방전에 따른 수명감소, 파열, 손상, 화재 등의 문제점이 발생하고 있다. 따라서 BMS(Battery Management System)를 통하여 과도한 충·방전을 보호하고 성능을 향상시킨다. 하지만 실제 리튬이온 배터리를 사용하여 BMS의 차단 및 보호범위 설정하는 데 있어서 이차전지의 수명감소, 파열, 손상, 화재의 문제점이 따른다. 따라서 본 논문에서는 배터리 충방전기와 시뮬레이터를 활용하여 이차전지 중 사용이 높은 리튬이온 배터리와 납축전지의 충전 및 방전 특성을 살펴본다.

• 폴리머
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• 제26권1호
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• pp.45-52
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• 2002

고밀도 폴리에틸렌(HDPE)과 초고분자량 폴리에틸렌(UHMWPE)을 블렌딩한 고분자 구조를 갖는 리튬이온 2차 전지용 습식 separator를 제조하였으며, 그들의 고분자 블렌딩 및 연신 조건이 제반물성에 미치는 영향에 관해서 고찰하였다. Separator의 기계적 강도는 UHMWPE의 분자량 및 함량이 증가함에 따라 크게 향상되었으며, UHMWPE의 함량이 6 wt%이며 5배 연신 필름에서 약 $1000 kg/\textrm{cm}^2$의 기계적 강도를 보이며 제막성 또한 우수한 것으로 나타났다. Separator의 기공구조는 0.1~0.12 $\mu\textrm{m}$로 균일성을 보였으며, shut-down특성은 130 $^{\circ}C$ 부근에서 급격히 상승하여 $160^{\circ}C$에서 용융되는 것으로 나타났고 따라서 리튬이온 2차전지에 적용 가능한 것으로 평가되었다.

• Carbon letters
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• 제8권4호
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• pp.335-339
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• 2007

Carbon/silicon composites were synthesized by mixing silicon powders with petroleum pitch and subsequent heat-treatment. The resultant composites were composed of carbon and nano-size crystalline silicon identified by XRD and EDX. FIB images and SEM images were taken respectively to detect the existence of silicon impregnated in carbon and the distribution of silicon on the carbon surface. The obtained carbon/silicon materials were assembled as half cell anodes for lithium ion secondary battery and their electrochemical properties were tested. The pitch/silicon composite (3 : 1 wt. ratio) heat treated at $1000^{\circ}C$ and mixed with 55.5 wt.% of graphite showed relatively good electrochemical properties such as the initial efficiency of 78%, the initial discharge capacity of 605 mAh/g, and the discharge capacity of 500 mAh/g after 20 cycles.

• 한국전기전자재료학회논문지
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• 제11권9호
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• pp.727-732
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• 1998

Ag-deposited graphite powder was prepared by a chemical reduction method of metal particles onto graphite powder. X-ray diffraction observation of Ag-deposited graphite powder revealed that silver existed in a metallic state, but not in an oxidized one. From SEM measurement, ultrafine silver particles were highly dispersed on the surface of graphite particles. Cylindrical lithium ion secondary battery was manufactured using Ag-deposited graphite anodes and $LiCoO_2$ cathodes. The cycleability of lithium ion secondary battery using Ag-deposited graphite anodes was superior to that of original graphite powder. The improved cycleability may be due to both the reduction of electric resistance between electrodes and the highly durable Ag-graphite anode.

• Journal of Ceramic Processing Research
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• 제13권spc1호
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• pp.110-113
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• 2012

Ge-S and Li-Ge-S powders were synthesized via solution-based process in order to employ chalcogenide-based solid electrolyte for use in Li secondary batteries. GeCl4 and thioacetamide in combination result in Ge-S powders of which major crystalline phase becomes GeS2 where the tetragonal and orthorhombic phases coexist after heat treatment. A chemical treatment using NaOH brings about the reduction of chlorine in the powders obtained. However, the heat treatment at 300 ℃ is more effective in minimizing the chlorine content. When lithium chloride is used as the precursor of Li ions, the LiCl powders are agglomerated with an inhomogeneous distribution. When Li2S is used, the Li-Ge-S powders are distributed more uniformly and the orthorhombic GeS2 phase dominates in the powders.

• Journal of Electrochemical Science and Technology
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• 제3권2호
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• pp.63-67
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• 2012

We prepared various $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2-LiFePO_4$ mixed-cathode electrodes by changing the content of $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ and $LiFePO_4$ used, and we analyzed the electrochemical characteristics of the cathodes. We found that the reversible specific capacity of the cathodes increased and that the capacity retention ratios of the cathodes decreased during cycling as the content of $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ increased. Conversely, we found that although the reversible specific capacity of the cathodes decreased because of the material composition, the cycle property of the cathodes increased when the $LiFePO_4$ content increased. We analyzed the thermal stability of the $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2-LiFePO_4$ mixed-material cathodes by differential scanning calorimetry and found that it increased as the $LiFePO_4$ content increased.

• 전기화학회지
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• 제9권1호
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• pp.1-5
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• 2006

리튬이온전지용 음극 활물질로 스피넬 구조의 리튬 티탄산화물$(Li_4Ti_5O_{12})$이 졸겔법과 HEBM법으로 제조되었다. 제조된 $Li_4Ti_5O_{12}$의 입자크기 및 결정구조를 확인하기 위하여 X-선 회절분석(XRD), 주사전자현미경(SEM) 및 평균입자분석(PSA)을 수행한 결과 100nm의 균일한 크기의 입자를 확인하였다. 작업전극으로 $Li_4Ti_5O_{12}$를 사용하고 기준전극과 상대전극으로 lithium 호일을 사용하여 전기화학적인 삼상전극 셀을 구성하여 전기화학적인 특성 평가를 한 결과 $1.0\sim2.5V$의 전압 범위에서 고율 충 방전 성능과 0.2C에서 173mAh/g의 용량 특성을 나타내었다. $Li_4Ti_5O_{12}$은 리튬의 삽입과 탈리가 일어나는 동안 구조적인 안정성을 보여주고 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.299-305
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• 2003

The battery industries have been developed to the implementation of lithium ion secondary cell from the cell of Ni/Cd and Ni/MH in the past to be asked of an age of high technology from low technology. Also in resent the polymeric cell to get a good high function with an age of new advanced information system is changed from the 21 century to the secondary batteries society. The properties of lithium secondary batteries have the high energy density, the long cycle time, the low self discharge area and the high active voltage. The wanted properties of secondary batteries for the motion of an apparatuses of industries of an high skill age have a small type trend of the energy density and it is become with a strong asking of the industrial society market about the storable medium of the convenience and new power energy. The electrochemical properties is researched for the cell to be synthesised and crystallized the positive active material LiMnO2 of the secondary cell at 9250C to get a new improved data of the electric discharge for that the capacitance of the LiMnO2 thin film that is improving and researching with the properties and a merit and demerit in the this kind of asking.