• 한국재료학회지
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• 제12권9호
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• pp.712-717
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• 2002

New wet chemical method so called precipitation-evaporation method was suggested for preparing spinel structure lithium manganese oxide ($LiMn_2$$O_4$) for Li ion secondary battery. Using precipitation-evaporation method, $LiMn_2$$O_4$ cathode materials suitable for Li ion secondary batteries can be synthesized. Single spinel phase $LiMn_2$$O_4$ powder was synthesized at lower temperature compared to that of prepared by solid-state method. $LiMn_2$$O_4$ powder prepared by precipitation-evaporation method showed uniform, small size and well defined crystallinity particles. Li ion secondary battery using $LiMn_2$$O_4$ as cathode materials prepared by precipitation-evaporation method and calcined at $800^{\circ}C$ showed discharge capacity of 106.03mAh/g and discharge capacity of 95.60mAh/g at 10th cycle. Although Li ion secondary battery showed somewhat smaller initial capacity but good cyclic ability. It is suggested that electro-chemical properties can be improved by controlling particle characteristics by particle morphology modification during calcination and optimizing Li ion secondary battery assembly conditions.

• 전기화학회지
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• 제1권1호
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• pp.14-17
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• 1998

MPCF는 Li ion 2차전지용 부극 활물질로 연구되고 있다. 흑연화 MPCF는 높은 방전 용량과 우수한 충방전 효율을 가진다. $0\~1$ V전위영역에서 25 mA/g의 정전류로 충방전할 때의 MPCF/Li전지의 초기 방전 용량은 300 mAh/g이며, 충방전 효율은 $90\%$ 이상을 나타낸다. $LiCoO_2$을 정극 활물질로, 혼합 탄소재료를 부극 활물질로 사용하여 원통형 Li ion 2차전지를 제작하였다. Li ion 2차전지의 수명 특성을 향상하기 위하여, 흑연화 MPCF에 이종 탄소 재료를 $10 wt\%$ 혼합하였다. 혼합 탄소재료를 사용한 Li ion 2차전지의 수명 성능은 흑연화 MPCF만을 사용한 전지보다 우수하였다.

• Carbon letters
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• 제12권3호
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• pp.180-183
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• 2011

Li metal is accepted as a good counter electrode for electrochemical impedance spectroscopy (EIS) as the active material in Li-ion and Li-ion polymer batteries. We examined the existence of signal noise from a Li-metal counter quantitatively as a preliminary study. We suggest an electrochemical cell with one switchable electrode to obtain the exact impedance signal of active materials. To verify the effectiveness of the switchable electrode, EIS measurements of the solid electrolyte interphase (SEI) before severe $Li^+$ intercalation to SFG6 graphite (at > ca. 0.25 V vs. Li/$Li^+$) were taken. As a result, the EIS spectra without the signal of Li metal were obtained and analyzed successfully for the following parameters i) $Li^+$ conduction in the electrolyte, ii) the geometric resistance and constant phase element of the electrode (insensitive to the voltage), iii) the interfacial behavior of the SEI related to the $Li^+$ transfer and residence throughout the near-surface (sensitive to voltage), and iv) the term reflecting the differential limiting capacitance of $Li^+$ in the graphite lattice.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.627-628
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• 2005

In recent years, the rapid growth of portable electronic device market requires higher density characteristics of batteries. The speed at which portability and mobility is advancing hinges much on the battery. What is important is this energy source that engineers design handled devices around the battery, rather than the other way around. Much improvement has been made in reducing the power consumption of portable devices. Currently, the most popular secondary battery is Li-ion battery. Li-ion has won the limelight and become the most prominent battery. This paper reviews the prospect and future of the Li-ion battery.

• 한국세라믹학회지
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• 제37권5호
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• pp.466-472
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• 2000

As cathode materials of LiMn2O4-based lithium-ion secondary batteries, Li(Mn1-$\delta$M$\delta$)2O4 (M=Ni and Co, $\delta$=0, 0.05, 0.1 and 0.2) materials which Co and Ni are substituted for Mn, were syntehsized by the solid state reaction at 80$0^{\circ}C$ for 48 hours. No second phases were formed in Li(Mn1-$\delta$M$\delta$)2O4 system with substitution of Co. However, substitution of Ni caued to form a second phase of NiO when its composition exceeded over 0.2 of $\delta$ in Li(Mn1-$\delta$M$\delta$)2O4. As the results of charging-discharging test, the maximum capacity of Li(Mn1-$\delta$M$\delta$)2O4 appeared in $\delta$=0.1 for both Co and Ni. Also, Li(Mn1-$\delta$M$\delta$)2O4 electrode showed higher capacity and better cycle performance than LiMn2O4.

• 한국세라믹학회지
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• 제35권9호
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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.

• 한국인터넷방송통신학회논문지
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• 제23권4호
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• pp.171-176
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• 2023

21세기 현대사회에 있어서 이차전지 배터리(Battery)를 이용한 휴대용 전자제품은 계속해서 경량, 소형화되어가는 추세 속에서 있다. 그리고 이러한 추세와 더불어 우리는 몸에 착용할 수 있는 전자 장비를 이용하여 하루 일상생활에서 정보를 수집, 공유하는 4차 산업혁명 시대에 활동하고 있다. 따라서 소형 가전제품 및 디지털 기기를 사용하면서 재충전할 수 있는 이차전지 배터리의 역할은 점점 더 중요하게 증가하고 있다. 이러한 증가와 더불어 이차전지 배터리 성능시험은 특성, 수명, 고장진단, 재활용 등의 다양한 시험방법을 요구하고 있으며 있다. 또한 배터리의 안전과 적절한 기능을 보장하기 위한 배터리 테스트 시스템 구축과 이에 따른 지침 및 올바른 기본지식이 고려되고 있다. 따라서 본 논문에서는 배터리의 성능과 직접으로 연결된 시나리오별 충방전에 따른 이차전지 리튬이온(Li-ion) 배터리의 특성에 대해 살펴보고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.143-146
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• 1998

The $LiCoO_2$ powder was synthesized at >$700^{\circ}C$, >$850^{\circ}C$ by solution route. In this paper, we investigated X-ray diffraction, and charge-discharge performance for $LiCoO_2$/Li and $LiCoO_2$/MPCF cell. The $LiCoO_2$/Li ceSl exhibited a high avmge discharge potential of 38-3% and a good cycle life performance at 5(hnA/g during chargedischarge cycling between 43-3.0V. And, the $LiCoO_2$MPCF cell showed a high average discharge voltage of 3.6-3.W and a excellent cycle life prfomam during chargedischarge cycling b&wm 4 2-2.W. As a result, the $LiCoO_2$ powdm syd-eizd by solution route is a good cathode material for lithium ion secondary battery.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1054-1057
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• 1995

The pollution-free secondary Li ion battery has been developed recently. However due to short history of Li ion battery, the standards for characterized assessments and standardized testing methods have not been prepared and established yet. Also, the researches have not been done systematically regarding the operating methods of these new type of batteries. Such limited knowledge of new batteries emphasizes the importance of development of characterized assessment and the operating methods.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.25-28
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• 1998

Lithiated cobalt and nickel oxides are becoming very attractive as active cathode materials for secondary lithium ion secondary battery. $LiCoO_2$ is easily synthesized from lithium cobalt salts, but has a relatively high oxidizing potential on charge. LiNiOz is synthesized by a more complex procedure and its nonstoichiometry significantly degraded the charge-discharge characteristics. But $LiNiO_2$ has a lower charge potential which increases the system stability. Lithiated cobalt and nickel oxides are iso-structure which make the preparation of solid solutions of $LiNi_{1-x}Co_xO_2$ for O$LiCoO_2 and LiNiO_2$ electrode. The aim of the presentb paper is to study the electrochemical behaviour, as weU as the possibilities for practical application of layered Iithiated nickel oxide stabilized by $Co^{3+}$ substitution as active cathode materials in lithium ion secondary battery.