• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.105-108
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• 2011

The cycling behavior of $Li_4Ti_5O_{12}$ electrode in the ionic liquid (IL)-based electrolytes containing 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide and a small amount of additive (vinylene carbonate, ethylene carbonate, fluoroethylene carbonate) was investigated. The $Li_4Ti_5O_{12}$ electrode in the IL electrolyte with an additive exhibited reversible cycling behavior with good capacity retention. Electrochemical impedance spectroscopy and FTIR studies revealed that an electrochemically stable solid electrolyte interphase was formed on the $Li_4Ti_5O_{12}$ electrode in the presence of vinylene carbonate and ethylene carbonate during cycling.

• Corrosion Science and Technology
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• 제22권4호
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• pp.287-296
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• 2023

Li-ion batteries have been gaining increasing importance, driven by the growing utilization of renewable energy and the expansion of electric vehicles. To meet market demands, it is essential to ensure high energy density and battery safety. All-solid-state batteries (ASSBs) have attracted significant attention as a potential solution. Among the advantages, they operate with an ion-conductive solid electrolyte instead of a liquid electrolyte therefore significantly reducing the risk of fire. In addition, by using high-capacity alternative electrode materials, ASSBs offer a promising opportunity to enhance energy density, making them highly desirable in the automotive and secondary battery industries. In ASSBs, Li metal can be used as the anode, providing a high theoretical capacity (3860 mAh/g). However, challenges related to the high interfacial resistance between Li metal and solid electrolytes and those concerning material degradation during charge-discharge cycles need to be addressed for the successful commercialization of ASSBs. This review introduces and discusses the interfacial reactions between Li metal and solid electrolytes, along with research cases aiming to improve these interactions. Additionally, future development directions in this field are explored.

• 한국재료학회지
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• 제28권1호
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• pp.43-49
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• 2018

The demand for energy storage devices capable of operating at high temperatures is increasing. In order to operate at high temperatures, a device must have excellent thermal stability and no risk of explosion. Ionic liquids are electrolytes that satisfy the above conditions, and studies on improving their performance have attracted great interest. Here, we report the results of a study on the fabrication of a supercapacitor that has a composite electrolyte prepared by dispersing fumed silica in an ionic liquid. The fumed silica filler exhibits improved ionic conductivity and lower interfacial resistance. In particular, the silica nanoparticles with diameters of 10 nm exhibit better electrochemical properties than fillers of other diameters and have excellent device performance of 33 times higher than the pristine ionic liquid at high temperatures. This study can be used to improve the electrolytes of electrochemical devices, such as the next generation battery or lithium ion battery.

• Journal of Electrochemical Science and Technology
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• 제2권1호
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• pp.8-13
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• 2011

Interfacial compatibility between the Si-Cu electrode and diluted ionic liquid electrolyte containing 50 vol.% of 1M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide (MPP-TFSI) and 50 vol.% dimethyl carbonate (DMC) in a lithium cell and dilution effect on surface chemistry are examined. ex-situ ATR FTIR analysis results reveal that the surface of the Si-Cu electrode cycled in the diluted ionic liquid electrolyte is effectively passivated with the SEI layer mainly composed of carboxylate salts-containing polymeric compounds produced by the decomposition of DMC. Surface species by the decomposition of TFSI anion and MPP cation are found to be relatively in a very low concentration level. Passivation of electrode surface with the SEI species contributes to protect from further interfacial reactions and to preserve the electrode structure over 200 cycles, delivering discharge capacity of > 1670 $mAhg^{-1}$ and capacity retention of 88% of maximum discharge capacity.

• 한국세라믹학회지
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• 제46권6호
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• pp.587-591
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• 2009

Lithium salt have been used mainly as electrolyte of thermal battery for electricity storage. Recently, The 3phase lithium salt(LiCl-LiF-LiBr) is tried to use as electrolyte of thermal battery for high electric power. It is reported that LiCl-LiF-LiBr salt have high ion mobility due to its high lithium ion concentration. Solid lithium salt is melt to liquid state at above $500{^{\circ}C}$. The lithium ion is easily reacted with support materials. Because the melted lithium ion has small ion size and high ion mobility. For the increasing mechanical strength of electrolyte pellet, the research was started to apply ceramic filter to support of electrolyte. In this study, authors used SiOC web and glass fiber filter as ceramic mat for support of electrolyte and impregnated LiCl-LiF-LiBr salt into ceramic mat at above $500{^{\circ}C}$. The fabricated electrolyte using ceramic mat was washed with distilled water for removing lithium salt on ceramic mat. The washed ceramic mat was observed for lithium ion reaction behavior with XRD, SEM-EDS and so on.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.608-612
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• 2012

We investigated the cycling behavior of $Li_4Ti_5O_{12}$ electrode in a cross-linked gel polymer electrolyte based on non-flammable ionic liquid consisting of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide and vinylene carbonate. The $Li_4Ti_5O_{12}$ electrodes in ionic liquid-based gel polymer electrolytes exhibited reversible cycling behavior with good capacity retention. Cycling data and electrochemical impedance spectroscopy analyses revealed that the optimum content of the cross-linking agent necessary to ensure both acceptable initial discharge capacity and good capacity retention was about 8 wt %.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.143.2-143.2
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• 2010

Therefore, with this development assignment we'd like to develop the hybrid system combining 800W DMFC (Direct Methanol Fuel Cell) and 1.6kW of Lithium secondary battery pack which can be applied to the most common small cart. a scooter, to secure the development capability of hundreds of Watts DMFC, the high-capacity Lithium secondary battery pack, the technology of BMS (Battery Management System) and the development technology of hybrid system. DMFC, in fact, has lower energy efficiency than PEMFC (Polymer Electrolyte Membrane Fuel Cell); however, it has several advantages in terms of fuel storage and use. It is pretty easy to be stored and used without any additional colling and heating devices because of its insensitive liquid methanol to temperature. In conclusion, DMFC system is the most suitable device for small mobile vehicles.

• Korean Chemical Engineering Research
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• 제53권5호
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• pp.638-645
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• 2015

Vanadium redox flow batteries (VRFBs) have been investigated for their potential utility as large energy storage systems due to their advantageous performances in terms of long cycle life, high energy efficiency, low cost, and flexible design. Carbon materials are typically used as electrodes in redox reactions and as a liquid electrolyte support. The activities, surface areas, and surface morphologies of porous carbon materials must be optimized to increase the redox flow battery performance. Here, to reduce the resistance in VRFBs, surface-modified carbon felt electrodes were fabricated, and their structural, morphological, and chemical properties were characterized. The surface-modified carbon felt electrode improved the cycling energy efficiencies in the VRFBs, from 65% to 73%, due to the improved wettability with electrolyte. From the results of impedances analysis with proposed fitting model, the electrolyte-coupled polarization in VRFB dramatically decreased upon modification of carbon felt electrode surface. It is also demonstrated that the compressibility of carbon felt electrodes was important to the VRFB polarization, which are concerned with mass transfer polarization. The impedance analysis will be helpful for obtaining better and longer-lived VRFB performances.

• 공업화학전망
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• 제23권1호
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• pp.30-41
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• 2020

최근 전기차, 신재생에너지 등장 등으로 중대형 이차전지 시장이 확대되면서, 리튬 이온 배터리 안전성 이슈 관련 고안전성 전해액 소재에 대한 관심이 높아졌다. 다양한 고안전성 전해액 시스템 중, 상온 이온성 액체는 비발화성, 낮은 증기압 특성으로 많은 관심을 받고 있다. 뛰어난 물리적 특성에도 불구하고 리튬 이온 배터리의 전해액으로 사용되기 위해서는 전도도 및 전기화학 안전성, 전극 계면 거동이 전기화학 성능을 얻는데 만족되어야 한다. 많은 종류의 상온 이온성 액체들이 분자 구조 설계 및 양극/음극 전해액 사용, 전지 내 부품 안전성 확보 등의 다양한 접근 방법들로 연구가 진행되어 왔다. 향후 지속적인 전지 안전성의 이슈에 대한 중요성 증대로 상온 이온성 액체에 대한 연구 역시 더 활발해질 것으로 기대되며, 본 기고문에서는 다양한 상온 이온성 액체들이 전지 시스템에 적용된 연구동향에 대해서 정리하고 소개하고자 한다.

• 전기화학회지
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• 제17권3호
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• pp.156-163
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• 2014

본 연구에서는 불소계 실란을 첨가제로 사용하여 전해액의 열화 반응을 억제함으로써 리튬이온전지의 싸이클 특성을 향상시키고자 하였다. 첨가제로 사용된 trifluoropropyltrimethoxysilane은 리튬염과 카보네이트계 유기 용매로 이루어진 액체 전해질보다 전기화학적 산화, 환원 분해반응이 먼저 일어나 음극 및 양극 표면에서 안정적인 고체전해질계면 (solid electrolyte interphase, SEI) 막을 형성하며, 5 wt.%의 첨가제를 포함하는 경우 가장 우수한 전기화학적 특성을 나타내었다. SEM 및 XPS 분석을 통해 전극 표면에 생성된 피막의 화학 성분을 분석하였으며, 이들 결과로부터 새로운 SEI 형성 첨가제로서 불소계 실란의 가능성을 확인하였다.