• 한국진공학회지
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• 제16권3호
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• pp.227-230
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• 2007

리튬이온 제조공정에서 전해질 주입 후 반드시 거쳐야 하는 숙성공정은 일반적으로 별로 중요하게 다루어 지지 않고 있다. 왜냐하면 전지 숙성공정이 전지성능에 영향을 주는 인자에 대하여 그다지 깊이 있게 연구가 되어있지 않기 때문이다. 하지만 숙성공정 중에 나타나는 OCV 변화는 전해질 내에 포함되어 있는 성분이 전극으로 전기화학적 흡착되어 나타나는 현상으로 SEI 피막 형성에 매우 중요한 역할을 하게 된다. 이에 본 연구에서는 숙성기간 중에 변하게 되는 OCV와 SEI피막의 관계, 그리고 전지성능과의 연계에 대하여 깊이 있게 논의하고자 한다.

• Journal of Electrochemical Science and Technology
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• 제15권1호
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• pp.168-177
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• 2024

Ni-rich cathode is one of the promising candidates for high-energy lithium-ion battery applications. Due to its specific capacity, easy industrialization, and good circulation ability, Ni-rich cathode materials have been widely used for lithium-ion batteries. However, due to the limitation of the co-precipitation method, including sewage pollution, and the instability of the long production cycles, developing a new efficient and environmentally friendly synthetic approach is critical. In this study, the Ni_0.91Co_0.06Mn_0.03CO₃ precursor powder was successfully synthesized by an efficient spray-drying method using carbonate compounds as a raw material. This Ni_0.91Co_0.06Mn_0.03CO₃ precursor was calcined by mixing with LiOH·H₂O (5 wt% excess) at 480℃ for 5 hours and then sintered at two different temperatures (780℃/800℃) for 15 hours under an oxygen atmosphere to complete the cathode active material preparation, which is a key component of lithium-ion batteries. As a result, LiNi_0.91Co_0.06Mn_0.03O₂ cathode active material powders were obtained successfully via a simple sintering process on the Ni_0.91Co_0.06Mn_0.03CO₃ precursor powder. Furthermore, the obtained LiNi_0.91Co_0.06Mn_0.03O₂ cathode active material powders were characterized. Overall, the material sintered at 780℃ shows superior electrochemical performance by delivering a discharge capacity of 190.76 mAh/g at 1^st cycle (0.1 C) and excellent capacity retention of 66.80% even after 50 cycles.

• 자원리싸이클링
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• 제14권6호
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• pp.37-43
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• 2005

페리튬이온전지로부터 회수된 코발트와 리튬 침출액으로부터 화염분부열분해법에 의하여 $LiCoO_{2}$ 나노분말을 제조하였다. 리튬 및 코발트 성분을 함유하는 전극물질은 열처리 및 기계적 처리에 의해 그 농도를 증가 시켰다. 리튬이온전지 양극물질을 질산으로 용해한 다음 침출액중 Li과 Co의 당량비가 1.0 되도록 $LiNO_{3}$로 조절하여 화염분무열분해용 전구체를 제조하었다. 화염분무열분해법에 의해 제조된 $LiCoO_{2}$ 분말의 평균입자크기는 전구체의 몰 농도가 증가하면서 증가되었으며, 화염온도 역시 입자의 크기를 증가시켰다. 변수실험 결과 $11{\~}35nm$ 크기의 결정형 $LiCoO_{2}$ 나노분말을 제조할 수 있었다 또한 나노 $LiCoO_{2}$의 전극재료로서의 가능성을 확인하기 위하여 충방전 특성 평가와 같은 전기화학적 분석을 수행하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1220-1221
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• 2006

[ $LiMn_2O_4$ ] powders for lithium ion batteries were synthesized from two separate raw material pairs of LiOH/MnO and $LiOH/MnO_2$. The powders prepared at 780 and $850^{\circ}C$ and their difference of electrochemical properties were investigated. Both powders calcined at 780 and $850^{\circ}C$ were composed of a single-phase spinel structure but those treated at $850^{\circ}C$ showed a lower intensity ratio of $I_{311}$ to $I_{400}$, a slightly larger lattice parameter, and an increased discharge capacity by 10% under $3.0{\sim}4.3V$ voltage range. The XPS study on the oxidation states of manganese repealed that powders made from LiOH/MnO had less $Mn^{3+}$ ion and gave better battery performances than those from $LiOH/MnO_2$.

• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.424-430
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• 2021

The element iron (Fe) is affordable and abundantly available, and thus, it finds use in a wide range of applications. As regards its application in rechargeable lithium-ion batteries (LIBs), the electrochemical reactions of Fe must be clearly understood during battery charging and discharging with the LIB electrolyte. In this study, we conducted systematic electrochemical analyses under various voltage conditions to determine the voltage at which Fe corrosion begins in general lithium salts and organic solvents used in LIBs. During cyclic voltammetry (CV) experiments, we observed a large corrosion current above 4.0 V (vs. Li/Li⁺). When a constant voltage of 3.7 V (vs. Li/Li⁺), was applied, the current did not increase significantly at the beginning, similar to the CV scenario; on the other hand, at a voltage of 3.8 V (vs. Li/Li⁺), the current increased rapidly. The impact of this difference was visually confirmed via scanning electron microscopy and optical microscopy. Our X-ray photoelectron spectroscopy measurements showed that at 3.7 V, a thick organic solid electrolyte interphase (SEI) was formed atop a thin fluoride SEI, which means that at ≥3.8 V, the SEI cannot prevent Fe corrosion. This result confirms that Fe corrosion begins at 3.7 V, beyond which Fe is easily corrodible.

• Corrosion Science and Technology
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• 제22권6호
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• pp.466-477
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• 2023

The increasing demand for high-performance energy storage systems has highlighted the limitations of conventional Li-ion batteries (LIBs), particularly regarding safety and energy density. All-solid-state batteries (ASSBs) have emerged as a promising next-generation energy storage system, offering the potential to address these issues. By employing nonflammable solid electrolytes and utilizing high-capacity electrode materials, ASSBs have demonstrated improved safety and energy density. Automotive and energy storage industries, in particular, have recognized the significance of advancing ASSB technology. Although the use of Li metal as ASSB anode is promising due to its high theoretical capacity and the expectation that Li dendrites will not form in solid electrolytes, persistent problems with Li dendrite formation during cycling remain. Therefore, the exploration of novel high-performance anode materials for ASSBs is highly important. Recent research has focused extensively on alloy-based anodes for ASSBs, owing to their advantages of no dendrite formation and high-energy density. This study provides a comprehensive review of the latest advancements and challenges associated with alloy-based anodes for ASSBs.

• 전기전자학회논문지
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• 제23권2호
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• pp.667-674
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• 2019

최근 발생한 원전 사고는 소외전원 및 비상전원의 기능이 상실되어 발전소 전체 정전이 발생한 사례를 계기로 원전의 비상전원공급용 배터리의 중요성이 부각되고 있다. 현재 원전의 비상전원공급용 배터리는 기존의 납축전지를 대신하여 리튬계열 배터리로 교체가 고려되고 있는 상황이다. 이에 따라 원통형 리튬 배터리의 적용성을 판단하기 위해 여러 가지 리튬 계열 배터리의 전기적 특성 실험을 진행하여 결과를 분석해야 한다. 본 논문은 현재 ESS(Energy Storage Systems)에 많이 사용되는 세 가지 타입의 리튬 배터리의 전기적 특성실험을 통해 적절한 배터리 타입을 선정하고, 선정된 배터리가 비상전원공급용 배터리로 사용될 때 최적의 C-rate를 제안한다. 또 배터리 모델링을 통해 배터리의 상태를 추정하며 문제점을 제시한다.

• 한국항공우주학회지
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• 제42권4호
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• pp.351-359
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• 2014

본 논문에서는 저궤도 소형인공위성에서 위성의 각 부에 전원을 공급하기 위한 리튬이온 배터리 시스템의 신뢰성 확보를 위해 수행한 우주인증시험들의 결과를 나타내었다. 리튬이온 배터리 시스템의 신뢰성을 검증하기 위하여 구조해적, 성능시험, 우주 및 발사환경에서의 환경시험 등을 수행하였다. 모든 해석 및 시험 결과가 요구조건에 만족함을 보임으로써 리튬이온 배터리를 적용한 소형인공위성의 신뢰성을 검증하고 제고할 수 있었다.

• Journal of Power Electronics
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• 제14권1호
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• pp.135-142
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• 2014

In the design of battery chargers, limiting the output ripple current according to the manufacturer's recommendation is important for reliable service and extended battery life. Ripple components can cause internal heating of the battery and thus reduce the service life of the battery. Care must be exerted in the design of the switching converter for the charge application through the accurate estimation of the output current ripple value. This study proposes a method to reduce the output current ripple of the converter and presents a detailed analysis of the output current ripple of the DC-DC boost converter to provide a guideline for the design of the battery charger.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.46-47
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• 2012

In the design of the battery charger it is important to limit the ripple current and voltage according to the manufacturer's recommendation for the reliable service and the extended life of the battery. However, it is often overlooked that these ripple components can cause internal heating of the battery, thereby reducing its service life. Thus the care must be taken in the design of the switching converter for the charge application through the accurate estimation of the output ripple values. In this research analysis on the output ripple of the dc-dc converter is detailed to provide a guideline for the design of the battery charger.