• 멤브레인
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• 제27권1호
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• pp.92-103
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• 2017

본 연구에서는 리튬이온전지용 친수화된 세퍼레이터의 전기화학적 성능에 대한 연구를 진행하였다. 리튬이온전지용 분리막으로 사용되는 폴리올레핀 소재는 소수성이고, 카보네이트 계열의 유기용매를 사용하는 전해액은 친수성을 가진다. 따라서 리튬이온전지는 수계전해액을 사용하기 때문에 폴리올레핀계 분리막에 다양한 친수성 고분자를 도입하여 친수화 처리하였다. 코팅된 세퍼레이터의 변화를 평가하기 위해, 표면 관찰, 코팅시간에 따른 친수화도, 다공성, 젖음성에 대한 특성평가를 수행하였다. 최종적으로 리튬이온이 코팅된 세퍼레이터의 저항과., 이온전도도를 측정하여 리튬이온전지 성능평가를 진행하였다. PMVE로 코팅한 세퍼레이터의 친수화 정도가 우수하며, 세퍼레이터의 기공이 잘 유지되어 우수한 이온전도도를 나타냄으로써 이차전지 배터리에 적용을 위한 잠재성을 가짐을 확인하였다.

• 한국안전학회지
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• 제36권5호
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• pp.1-9
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• 2021

With the convergence of the information and communication technologies, a new age of technological civilization has arrived. This is the age of intelligent revolution, known as the 4th industrial revolution. The 4th industrial revolution is based on technological innovations, such as robots, big data analysis, artificial intelligence, and unmanned transportation facilities. This revolution would interconnect all the people, things, and economy, and hence will lead to the expansion of the industry. A high-density, high-capacity energy technology is required to maintain this interconnection. As a next-generation energy source, lithium-ion batteries are in the spotlight today. However, lithium-ion batteries can cause thermal runaway and fire because of electrical, thermal, and mechanical abuse. In this study, thermal runaway was induced in 72.5 Ah NCM pouch-type lithium-ion batteries because of thermal abuse. The surface of the pouch-type lithium-ion batteries was heated by the hot plate heating method, and the effect of the rate of increase in the surface temperature on the thermal runaway trigger time was analyzed using Minitab 19, a statistical analysis program. The correlation analysis results confirmed that there existed a strong negative relationship between each variable, while the regression analysis demonstrated that the thermal runaway trigger time of lithium-ion batteries can be predicted from the rate of increase in their surface temperature.

• Corrosion Science and Technology
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• 제22권1호
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• pp.36-43
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• 2023

Single-crystal Ni-rich NCM is a material that has drawn attention in the field of lithium-ion batteries due to its high energy density and long cycle life. In this study, we investigated the properties of single-crystal NCM 811 and its potential for use in lithium-ion batteries. High-quality single crystals of NCM 811 were successfully synthesized by crystal growth via a flux method. The single-crystal nature of the samples was confirmed through detailed characterization techniques, such as scanning electron microscopy and x-ray diffraction with Rietveld refinement. The crystal structure and electrochemical performances of the single-crystal NCM 811 were analyzed and compared to its poly-crystal counterpart. The results indicated that single-crystal NCM 811 had electrochemical performance and thermal stability superior to poly-crystalline NCM 811, making it a suitable candidate for high-performance batteries. The findings of this study contribute to a better understanding of the characteristics and potential of single-crystal NCM 811 for lithium-ion batteries.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2698-2700
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• 2010

• 폴리머
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• 제27권4호
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• pp.385-391
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• 2003

본 연구에서는 에틸렌 옥사이드의 반복 단위 길이 (n＝3, 7.3, 11.8, 그리고 16.3)가 다른 리튬 p-［메톡시 올리고(에틸렌옥시)］벤젠설폰산염 (LiEOnBS)을 합성하였다. 이 전해질 염을 이용하여 고분자 전해질을 제조하였으며, 에틸렌 옥사이드의 반복 단위 길이 및 농도에 따른 이온 전도도 그리고 리튬 이온의 운반율에 대해 조사하였다. 고분자 전해질의 이온 전도도는 3$0^{\circ}C$에서 4.89$\times$$10^{-4}$ S/cm (LiEO7.3BS, 0.5 M)로 최고 이온 전도도를 보였다. Dc분극과 ac 임피던스를 혼합하여 측정한 고분자 전해질의 리튬 이온의 운반율은 0.75~0.92 이였으며, 농도가 증가할수록 리튬 이온 운반율은 감소하였다. LiEO7.3BS의 전해질 염을 0.1 M로 사용한 고분자 전해질인 경우 0.92로 최고의 리튬 이온 운반율을 보였다. 이로부터 벤젠설포네이트에 치환된 에틸렌 옥사이드의 반복 단위가 3이상만 되어도 높은 리튬 이온 운반율을 가지는 단일 이온 전해질 특성을 보임을 알 수 있었다.

• 한국재료학회지
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• 제24권5호
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• pp.243-248
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• 2014

Silicon-carbon composite was prepared by the magnesiothermic reduction of mesoporous silica and subsequent impregnation with a carbon precursor. This was applied for use as an anode material for high-performance lithium-ion batteries. Well-ordered mesoporous silica(SBA-15) was employed as a starting material for the mesoporous silicon, and sucrose was used as a carbon source. It was found that complete removal of by-products ($Mg_2Si$ and $Mg_2SiO_4$) formed by side reactions of silica and magnesium during the magnesiothermic reduction, was a crucial factor for successful formation of mesoporous silicon. Successful formation of the silicon-carbon composite was well confirmed by appropriate characterization tools (e.g., $N_2$ adsorption-desorption, small-angle X-ray scattering, X-ray diffraction, and thermogravimetric analyses). A lithium-ion battery was fabricated using the prepared silicon-carbon composite as the anode, and lithium foil as the counter-electrode. Electrochemical analysis revealed that the silicon-carbon composite showed better cycling stability than graphite, when used as the anode in the lithium-ion battery. This improvement could be due to the fact that carbon efficiently suppressed the change in volume of the silicon material caused by the charge-discharge cycle. This indicates that silicon-carbon composite, prepared via the magnesiothermic reduction and impregnation methods, could be an efficient anode material for lithium ion batteries.

• 한국수소및신에너지학회논문집
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• 제26권5호
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• pp.416-422
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• 2015

Lithium Ion capacitor (LIC) is a new storage device which combines high power density and high energy density compared to conventional supercapacitors. LIC is capable of storing approximately 5.10 times more energy than conventional EDLCs and also have the benefits of high power and long cycle-life. In this study, LICs are assembled with activated carbon (AC) cathode and pre-doped graphite anode. Cathode material of natural graphite and artificial graphite kinds of MAGE-E3 was selected as the experiment proceeds. Super-P as a conductive agent and PTFE was used as binder, with the graphite: conductive agent: binder of 85: 10: 5 ratio of the negative electrode was prepared. Lithium doping condition of current density of $2mA/cm^2$ to $1mA/cm^2$, and was conducted by varying the doping. Results Analysis of Inductively Coupled Plasma Spectrometer (ICP) was used and a $1mA/cm^2$ current density, $2mA/cm^2$, when more than 1.5% of lithium ions was confirmed that contained. In addition, lithium ion doping to 0.005 V at 10, 20 and $30^{\circ}C$ temperature varying the voltage variation was confirmed, $20^{\circ}C$ cell from the low internal resistance of $4.9{\Omega}$ was confirmed.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3253-3256
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• 2013

Lithium is a highly attractive material for high-energy-concentration batteries, since it has low weight and high potential. Rechargeable lithium-ion batteries (LIBs), which have the extremely high gravimetric and volumetric energy densities, are currently the most preferable power sources for future electric vehicles and various portable electronic devices. In order to improve the efficiency and lifetime, new electrode compounds for lithium intercalation or insertion have been investigated for rechargeable batteries. Solid-state nuclear magnetic resonance (NMR) is a very useful tool to investigate the structural changes in electrode materials in actual working lithium-ion batteries. To detect the in-situ microstructural changes of electrode and electrolyte materials, $^7Li-^{19}F$ double-resonance solid-state NMR probe with a static solenoidal coil for a 600-MHz narrow-bore magnet was designed, constructed, and tested successfully.

• 한국가스학회지
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• 제14권3호
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• pp.14-20
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• 2010

본 논문은 리튬이온전지의 불꽃방전에 의한 폭발위험성에 관한 연구로서 휴대용기기의 전원으로 사용되는 리튬이온전지(일반용, 노트북용)를 시료로 선정하고, 폭발성 시험가스인 메탄, 프로판, 에틸렌, 수소를 대상으로 IEC형 불꽃점화 시험장치를 이용하여 불꽃점화실험을 실시하여 불꽃방전에 의한 폭발위험성을 규명하였다. 또한, 사고 시 단락전류에 의한 자체점화 가능성을 확인하고자 열화상카메라를 이용하여 온도변화를 측정하였다. 실험결과 리튜이온전지는 폭발성가스가 존재하는 폭발위험장소에서 사용할 때는 안전에 각별히 주의하여 사용 설계되어야 한다.

• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.451-456
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• 2007

Tetraazamacrocyclic ion exchangers tethered to Merrifield peptide resin (DTDM, TTTM) were prepared and the ion exchange capacity of these was characterized. The isotope separation of lithium was determined using breakthrough method of column chromatography. The isotope separation coefficient was strongly dependent on the ligand structure by Glueckauf's theory. We found that the isotope separation coefficients were increased as the values of distribution coefficients were increased. In this experiment the lighter isotope, 6Li was enriched in the resin phase, while the heavier isotope, 7Li in the solution phase. The ion radius of lighter isotope, 6Li was shorter than the heavier isotope, 7Li. The hydration number of lithium ion with the same charge became small as mass number was decreased. Because 6Li was more strongly retained in the resin than 7Li, the isotopes of lithium were separated with subsequent enrichment in the resin phase.