• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.398-406
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• 2022

In order to increase the electrochemical performance of thermal battery anode, LIFT anode having the same weight but a larger lithium content in electrodes was fabricated by mixing lithium, iron and titanium. By applying these electrodes, a single cell and a thermal battery were prepared, and the effect of LIFT anode on electrochemical performance was evaluated. The LIFT-applied single cell presented a better cell performance than LIFe-applied single cell at 500℃ and 550℃. The discharge performance of LIFT-applied single cell, which included the operating time (787s), specific capacity (1,683 Asg^-1), and electrode utilization (80.7%), was improved collectively compared to the LIFe applied single cell (736s, 1,245 As g^-1, and 74.6%) at 500℃. As the discharge progressed, the internal resistance of LIFT anode decreased, because the lithium migration path was formed due to the presence of large titanium particles among iron particles. These results were analyzed in terms of the microstructure of electrode using SEM. Energy density of LIFT-applied single cell also increased by 10% to 142.1 Wh kg^-1 compared to that of LIFe-applied single cell (127.4 Wh kg^-1). In addition, the LIFT-applied single cell presented a stable discharge performance for 6,500s without a short circuit which could occur by molten lithium under an open circuit voltage condition with a high pressure (4 kgf cm^-2). As observed in the high temperature thermal battery performance tests, the voltage and specific capacity of LIFT-applied thermal battery are superior to those of LIFe-applied thermal batteries, indicating that the energy density of LIFT-applied thermal batteries should remarkably increase.

• Carbon letters
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• 제12권4호
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• pp.243-248
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• 2011

Two different types of graphite, such as flake graphite (FG) and spherical graphite (SG), were used as anode materials for a lithium-ion secondary battery in order to investigate their electrochemical performance. The FG particles were prepared by pulverizing natural graphite with a planetary mill. The SG particles were treated by immersing them in acid solutions or mixing them with various carbon additives. With a longer milling time, the particle size of the FG decreased. Since smaller particles allow more exposure of the edge planes toward the electrolyte, it could be possible for the FG anodes with longer milling time to deliver high reversible capacity; however, their initial efficiency was found to have decreased. The initial efficiency of SG anodes with acid treatments was about 90%, showing an over 20% higher value than that of FG anodes. With acid treatment, the discharge rate capability and the initial efficiency improved slightly. The electrochemical properties of the SG anodes improved slightly with carbon additives such as acetylene black (AB), Super P, Ketjen black, and carbon nanotubes. Furthermore, the cyclability was much improved due to the effect of the conductive bridge made by carbon additives such as AB and Super P.

• 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.

• 전력전자학회논문지
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• 제26권6호
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• pp.421-428
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• 2021

Lithium-ion secondary batteries exhibit advantageous characteristics such as high voltage, high energy density, and long life, allowing them to be widely used in both military and daily life. However, the lithium-ion secondary battery does have its limitation; for example, the output power and capacity are readily decreased due to the increased internal impedance during discharging at a lower temperature (-32℃, military requirement). Also, during charging at a lower temperature, lithium dendrite growth is accelerated at the anode, thereby decreasing the battery capacity and life as well. This paper describes a study that involves increasing the internal temperature of lithium-ion secondary battery by energy circulation operation in a low-temperature environment. The energy circulation operation allows the lithium-ion secondary battery to alternately charge and discharge, while the internal resistance of lithium-ion battery acts as a heating element to raise its own temperature. Therefore, the energy circulation operation method and device were newly designed based on the electrochemical impedance spectroscopy of the lithium-ion secondary battery to mediate the battery performance at a lower temperature. Through the energy circulation operation of lithium ion secondary battery, as a result of the heat generated from internal resistance in an extremely low-temperature environment, the temperature of the lithium-ion secondary battery increased by more than 20℃ within 10 minutes and showed a 75% discharging capacity compared with that at room temperature.

• 대한화학회지
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• 제67권6호
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• pp.429-440
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• 2023

1,1-Dialkyl-2,5-bis(trimethylsilylethynyl)-3,4-diphenylsiloles (R=Et, i-Pr, n-Hex; 3a-c) were prepared and utilized as anode active materials for lithium-ion batteries; 3a was also used as a filler for the solid-state electrolytes (SSE). Siloles 3a-c were prepared by substitution reactions in which the two bromine groups of 1,1-dialkyl-2,5-dibromo-3,4-diphe- nylsiloles, used as precursors, were substituted with trimethylsilylacetylene in the presence of palladium chloride, copper iodide, and triphenylphosphine in diisopropylamine. Among siloles 3a-c, 3a had the best electrochemical properties as an anode material for lithium-ion batteries, including an initial capacity of 758 mAhg^-1 (0.1 A/g), which was reduced to 547 mAhg^-1 and then increased to 1,225 mAhg^-1 at 500 cycles. A 3a-composite polymer electrolyte (3a-CPE) was prepared using silole 3a as an additive at concentrations of 1, 2, 3, and 4 wt.%. The 2 wt.% 3a-CPE composite afforded an excellent ionic conductivity of 1.09 × 10^-3 Scm^-1 at 60℃, indicating that silole 3a has potential applicability as an anode active material for lithium-ion batteries, and can also be used as an additive for the SSE of lithium-ion batteries.

• Korean Chemical Engineering Research
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• 제49권5호
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• pp.554-559
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• 2011

리튬금속을 음전극으로 사용할 때의 안전성과 전극 특성을 개선하기 위해, 리튬금속 표면에 각기 종류가 다른 3가지의 탄소분말을 리튬금속 표면에 물리적으로 코팅한 전극을 제조하고 이를 리튬 2차전지의 음전극으로 채택하여 충방전 특성을 조사하였다. 일차입자의 입경이 작고 비표면적이 큰 탄소분말로 코팅한 음전극을 채택하는 경우가 충진밀도가 높고 표면 거칠기가 낮으며, 충방전 특성도 우수하게 나타났다. 이러한 탄소분말 코팅 효과는 소형 셀일수록 더욱 유리하게 나타났다.

• 전기화학회지
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• 제15권3호
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• pp.154-159
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• 2012

Si계 음극소재는 리튬 삽입-탈착 중 일어나는 큰 구조적 부피변화와 입도변화로 인해 빠른 성능 퇴화가 일어나는 단점이 있다. 산화물 SiO 음극소재는 리튬과의 반응 중 비활성상인 $Li_2O$ 및 lithium silicate가 형성되어 Si의 부피변화를 완화시키는 버퍼 역할을 하므로 용량은 Si보다 적으나 개선된 용량 유지 특성을 보이는 것으로 알려져 있다. 본 연구에서는 Si의 부피변화 완화를 위하여 저가의 $SiO_2$와 입자간 전기전도성을 향상시키는 흑연을 구조안정화 기재로서 사용하여 Si-$SiO_2$-흑연 복합재 음극을 제작하였다. 구조안정화 뿐만 아니라 silane계 전해액 첨가제를 이용하여 Si-$SiO_2$-흑연 복합재 음극과 전해액간 계면을 안정화시킴으로써 용량 유지 특성이 개선되는 효과에 대해 보고하고자 한다.

• 공업화학
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• 제29권6호
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• pp.635-644
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• 2018

리튬 이온 배터리는 휴대용 전자 제품, 전기 자동차 및 그리드 규모의 에너지 저장 장치 등과 같이 일상 생활에서 다양한 용도로 널리 사용되고 있다. 최근 높은 에너지 밀도, 경량 및 저비용과 같은 상업적 요구를 만족하는 리튬 이온 배터리 전극 소재 개발을 위하여 상당한 노력이 진행되어 오고 있다. 이 총설에서는 리튬 이온 배터리 양극 및 음극 재료의 원리와 최근 연구 동향을 요약하였으며, 특히 전극 소재의 설계 및 고급 특성화 기술을 강조하였다.

• 한국세라믹학회지
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• 제54권5호
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• pp.438-442
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• 2017

This paper reports the facile synthesis of microlamella-structured porous copper (Cu)-oxide-based electrode and its potential application as an advanced anode material for lithium-ion batteries (LIBs). Nanowire-like Cu oxide, which is created by a simple thermal oxidation process, is radially and uniformly formed on the entire surface of Cu foam that has been fabricated using a combination of water-based slurry freezing and sintering (freeze casting). Compared to the Cu foil with a Cu oxide layer grown under the same processing conditions, the Cu foam anode with 63% porosity exhibits over twice as much capacity as the Cu foil (264.2 vs. 131.1 mAh/g at 0.2 C), confirming its potential for use as an anode electrode for LIBs.

• 한국응용과학기술학회지
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• 제40권6호
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• pp.1191-1200
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• 2023

The lithium ion battery has applied to various fields of energy storage systems such as electric vehicle and potable electronic devices in terms of high energy density and long-life cycle. Despite of various research on the electrode and electrolyte materials, there is a lack of research for investigating of the binding materials to replace polymer based binder. In this study, we have investigated petroleum pitch/polymer composite with various ratios between petroleum pitch and polymer in order to optimize the electrochemical and physical performance of the lithium-ion battery based on petroleum pitch/polymer composite binder. The electrochemical and physical performances of the petroleum pitch/polymer composite binder based lithium-ion battery were evaluated by using a charge/discharge test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and universal testing machine (UTM). As a result, the petroleum pitch(MP-50)/polymer(PVDF) composite (5:5 wt % ratio) binder based lithium-ion battery showed 1.29 gf mm^-1 of adhesion strength with 144 mAh g^-1 of specific dis-charge capacity and 93.1 % of initial coulombic efficiency(ICE) value.