• Prospectives of Industrial Chemistry
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• v.23 no.1
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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.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.68-68
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• 2012

유기 용매를 사용하여 상온에서 실리콘계 전해 도금층을 형성하였다. 도금층의 몰폴로지는 전류밀도 및 도금 시간에 크게 영향을 받았으며, 다공성 구조에서 치밀한 구조까지 다양하게 나타났다. 조성 및 구조가 잘 정의된 실리콘계 전해 도금 층을 리튬이차전지용 애노드 활물질로써 평가해 본 결과 도금층 내 실리콘은 리튬과 가역적으로 반응하였다.

• Resources Recycling
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• v.21 no.6
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• pp.45-50
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• 2012

The room-temperature electrodeposition of metallic lithium was investigated from ionic liquid, 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) with lithium bis (trifluoromethanesulfonyl)imide (LiTFSI) as a lithium source. Cyclic voltammograms on gold working electrode showed the possibility of the electrodeposition of metallic lithium, and the reduction current on a gold electrode was higher than the value on platinum and copper. The metallic lithium could be electrodeposited on the gold electrode under potentiostatic condition at -2.4 V (vs. Pt-QRE) and was confirmed by analytical techniques including XRD and SEM-EDS. The dendrite-typed electrodeposits were composed of a metallic lithium and a alloy with gold substrate. And any impurity could be detected except for trace oxygen introduced during handling for the analyses.

• Food Science and Preservation
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• v.10 no.1
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• pp.1-5
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• 2003

This study was carried out to extend a marketing shelf-life of the Jeju greenhouse mandarin fruits. Total soluble solids were not showed any significant differences by the temperatures and pre-treatments during the marketing period. Acid content and firmness of the fruits were gradually decreased, which were better in cold than in room temperature treatment. The fruits washed in electrolyzed acid water(pH 2.4∼2.7) maintained freshness higher than those of control Internal CO$_2$concentration of those was 1.0 ％ more or less in the beginning marketing stage, but increased along the marketing period in mom temperature. Especially Internal CO$_2$concentration of wax-coated fruits rapidly increased more than any other, whereas it was a little decreased in cold treatment. After 10 days in room temperature, decay ratio of the fruits was below 4.0% in electrolyzed acid water washing, compared to 10.4% in control. After 30 days in cold temperature, decay ratio was only 3.7% in electrolyzed acid water washing compared to 4.4% of wax-coated treatment and 7.4% of control. The weight loss among the pre-treatments in room temperature had no significant differences and was higher than in cold one.

• Resources Recycling
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• v.27 no.4
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• pp.29-35
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• 2018

In this study, the electrochemical redox behavior of neodymium in non-aqueous electrolytes was investigated to confirm the possibility of neodymium metallurgy at room temperature. The non-aqueous electrolytes include ionic liquids such as $[C_4mim]PF_6$, $[C_4mim]Cl$, and $[P_{66614}]PF_6$, ethanol which are highly soluble in neodymium salts, and mixed electrolytes based on carbonate with highly electrochemical stability. The electrochemical redox properties of neodymium were better than those of other electrolytes in the case of the mixed electrolyte based on ethylene carbonate (EC)/di-ethylene carbonate (DEC). Ethanol was added to improve the physical properties of the mixed electrolyte. Thorough the analysis about ionic conductivity of EC/DEC ratio, ethanol content and $NdCl_3$ concentration, the best electrolyte composition was 50 vol% content of ethanol and 0.5 M of $NdCl_3$. Using cyclic voltametry and linear sweep voltametry, a current peak estimated at -3.8 V (vs. Pt-QRE) was observed as a limiting current of neodymium reduction. Potentiostatic electrolysis for 18 hours at room temperature at -6 V (vs. Pt-QRE) confirmed that metallic neodymium was electrodeposited.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.214-214
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• 2003

고체 고분자 전해질에 대한 연구는 1979년 wright와 Armand에 처음 시작된 이래로 지난 20여년간 연구가 계속적으로 지속되고 있다. 전지의 적용되기 위해 전해질이 갖추어야 할 조건중에 이온전도도가 상온에서 10-4 S/cm 이상의 전도도를 나타내야 하지만 지금까지 연구되고 있는 여러 고체 고분자 전해질은 이런 조건을 만족시키지 못하고 있는 실정이다. 본 연구에서는 이런 상온에서의 이온 전도성을 향상시키기 위해 여러 종류의 실리카와 세라믹 계열의 첨가제를 첨가하여 이온전도성의 향상을 꾀하고자 하였다. 본 연구에서는 고체 고분자 전해질의 host polymer로써 분자량 400,000 의 Polyethylene oxide를 사용하였으며 Lithuim salt로는 Lithium (bisperfluroethylsulfonyl)imide(3M)를 기본적으로 사용하였다. 여기에 가소제의 역활로써 (3-cyanopropyl)methylsiloxane cyclics를 첨가하였고 표면그룹이 CH3와 OH기로 이루어진 기능성 나노 실리카를(<11nm)이용하여 함량별 전기 화학적 특성 및 기본 물성을 측정하였다. 기본적으로 이 네 가지 물질을 유기용매 Acetonitril에 잘 용해하여 Solid Casting방법으로 80-100 마이크로의 복합고분자 전해질을 제조하였다. Homogeneous하고 uniform한 필름 제조하기 위해 9$0^{\circ}C$에서 열처리를 24h 동안 실시하였다. 제조되어진 복합고분자전해질은 XRD를 통하여 결정성을 조사하였고 DSC를 이용하여 유리 전이온도 및 결정화도를 조사하였다. 복합고체고분자의 전기화학적 성질을 평가하기 위해 blocking electrode를 제작하여 임피던스 스펙트로 스코피를 이용하여 이온전도성을 측정하였다. 또한 복합 고분자 전해질의 온도의존성에 대해서도 조사하였다. 또한 실제 전지의 작동구간에서의 전해질의 안정성을 확인하기 위해 LSV를 측정하였고. Li metal을 사용하여 non-blocking electrode를 제작하여 복합고분자 전해질과의 계면저항을 측정하였다.

• Journal of the Korean Electrochemical Society
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• v.25 no.3
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• pp.105-112
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• 2022

For the commercialization of all-solid-state batteries, it is essential to develop a solid electrolyte that can be operable at room temperature, and it is necessary to manufacture all-solid-state batteries by adopting materials with high ionic conductivity. Therefore, in order to increase the ionic conductivity of the existing oxide-based solid, Li₇La₃Zr₂O₁₂ (LLZO) doped with heterogeneous elements was used as a filler material (Al and Nb-LLZO). An electrolyte with garnet-type inorganic filler doped was prepared. The binary metal element and the polymer mixture of poly(ethylene oxide)/poly(propylene carbonate) (PEO/PPC) (1:1) are uniformly manufactured at a ratio of 1:2.4, The electrochemical performance was tested at room temperature and 60 ℃ to verify room temperature operability of the all-solid-state battery. The prepared composite electrolyte shows improved ionic conductivity derived from co-doping of the binary elements, and the PPC helps to improve the ionic conductivity, thereby increasing the capacity of all-solid-state batteries at room temperature as well as 60 ℃. It was confirmed that the capacity retention rate was improved.

• Journal of the Korean Electrochemical Society
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• v.2 no.1
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• pp.1-4
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• 1999

A lithium ion battery with polymer electrolyte is expected as a safe and long cycle life battery. This paper reports primarily the recent development results of a solid polymer electrolyte, which is a key factor of the secondary battery system, that has been obtained during the process of the development of a polymer type lithium battery. As a successful result of the solid polymer electrolyte. The ionic conductivity of the solid polymer electrolyte, which is composed of polyacrylonitrile and $LiClO_4\;with\; Al_2O_3$ dissolved as the supporting electrolyte, has been confirmed to be $2.3\times10^{-4} S/cm$ at room temperature.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.303-304
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• 2012

공업적으로 널리 사용되는 내식강의 전해연마는 주로 고농도의 인산염 전해액 기반에 황산과 질산 첨가된 용액에서 $70^{\circ}C$ 이상의 고온에서 행해지다 보니 폐액 처리와 작업 환경이 좋지 않아 기피 기술로 인식 되어 있다. 본 연구에서는 환경 친화적인 상온 공정을 개발 하고자 에틸렌 글리콜 용액에 여러 가지 첨가제를 첨가하여 그 효과를 살펴보고 최적 조성과 공정 조건을 확립 하고자 하였다. 틸렌 글리콜에 물과 질산 암모니움을 첨가하여 점도와 pH, 전류 전압 특성을 구하고 여기에 첨가제인 설파메이트와 암모니움 클로라이드 첨가량을 정하고 각각의 효과를 확인 하였다. 이러한 결과를 바탕으로 SUS 316 재질에 대한 최적 연마조건을 설정하기 위해 조도 변화, 광택도 및 표면 조직 변화와 전해연마기구를 비교 검토하였다.

• Polymer(Korea)
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• v.31 no.3
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• pp.263-268
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• 2007

Most of current works on the PEO-salt electrolytes has been focused on the enhancement of ionic conductivity with an addition of nano-ceramic fillers, but the significant drop of the conductivity with storage time is still in question and has been frequently overlooked. The conductivity drop with aging time has been assumed to come from the incorporation of ceramic particles. However, according to authors, the reported high-temperature values of the conductivity of pure $PEO_8LiCIO_4$ electrolytes are nearly in agreements, but the low temperature values are in great discrepancy reaching up to 10000 times. It indicates that the conductivity at ambient temperature is greatly dependent on the thermal history and sample preparations. In this paper, we showed that the ionic conductivities of both $PEO_8LiCIO_4$ and $PEO_8LiClO_4/Al_2O_3$ polymer electrolytes are strongly dependent on the thermal pretreatment and aging time. The conductivity drop with aging time of both ceramic-free and ceramic composite electrolytes has been measured to be nearly parallel. We showed that the conductivity relaxation with aging time is inherent irrespective of the incorporation of nano-ceramic fillers, since the PEO electrolytes at ambient temperature are in two-phase nature being in non-equilibrium state, never reaching completion.