• 전기화학회지
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• 제13권2호
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• pp.110-115
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• 2010

The plasticized polymer electrolytes based on polyvinylidene fluoride-co-hexafluoropropylene (P(VdF-co-HFP)), tetra (ethylene glycol) dimethyl ether (TEGDME), and lithium perchlorate ($LiClO_4$) are prepared for the lithium sulfur batteries by solution casting with a doctor-blade. The polymer electrolyte with EO : Li ratio of 16 : 1 shows the maximum ionic conductivity, $6.5\;{\times}\;10^{-4}\;S/cm$ at room temperature. To understand the effect of the salt concentration on the electrochemical performance, the polymer electrolytes are characterized using electrochemical impedance spectroscopy (EIS), infrared spectroscopy (IR), viscometer, and differential scanning calorimeter (DSC). The optimum concentration and mobility of the charge carriers could lead to enhance the utilization of sulfur active materials and the cyclability of the Li/S unit cell.

• 한국수소및신에너지학회논문집
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• 제20권3호
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• pp.238-244
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• 2009

We investigated the electrochemical properties of lithium/molybdenum sulfide(Li/MoS$_2$) using tetra (ethylene glycol) dimethyl ether(TEGDME) electrolyte. The Li/TEGDME/MoS$_2$ cell showed the first discharge capacity of 288mAhg$^{-1}$. From the XRD, SEM results of the MOS$_2$ electrode in various cut-off voltage during charge-discharge process, MoS$_2$ partly changed into Li$_2$S and Mo during discharge and Li$_2$S partly recovered into MOS$_2$ and Li during charge. Full charged MOS$_2$ electrode showed lump shape of big size, which might be related to agglomerate of MoS$_2$ particles. Therefore, the degradation might be related to decrease of active material for electrochemical reaction by agglomeration of MOS$_2$.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1299-1304
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• 2014

The electrochemical performance of Li-S cells was investigated in various ternary electrolyte solutions composed of 1,2-dimethoxyethane (DME), tetra(ethylene glycol) dimethyl ether (TGM), and 1,3-dioxolane (DOX). The discharge capacity values and cycle data obtained at each composition were statistically treated with the Minitab program to obtain mixture contour plots, from which the optimal composition of the ternary solvent systems was predicted. The discharge capacities and capacity retention were quite dependent on the electrolyte composition. It was estimated from the contour plots of the capacity at 1.0 C that the discharge capacity sharply increased with a decrease in the TGM content. High capacities greater than 900 mAh/g at 1.0 C were expected for the electrolyte composition with a volume ratio of DME/TGM/DOX = 1/0/1. In contrast, it was predicted from the mixture contour plot of the capacity retention that the cycle performance would significantly increase with an increase in the DME content.

• Elastomers and Composites
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• 제45권1호
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• pp.40-43
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• 2010

본 연구에서는 전기방사 장치의 드럼형태 컬렉터의 회전속도를 조절함으로써 제조된 섬유가 랜덤 또는 배향성 (1축, 2축)을 갖는 폴리이미드(PI) 나노섬유 매트를 제조하였다. 제조된 PI 매트의 구조를 전자현미경(SEM)을 통해 관찰한 결과 전술한 배향성을 확인할 수 있었다. 1 M 리튬트리풀루오로-메탄-설포네이트와 테트라-에틸렌 글리콜디메틸 에테르의 혼합용액에 PI 매트를 침지시킨 후 이온전도기로 이온전도도를 측정하였다. 2축배향 매트가 가장 높은 이온전도도를 나타내었다. 1축 배향의 경우 이온의 이동방향과 수직방향이 평행방향보다 이온전도도가 낮게 나타났고, 아울러 일정한 주기성을 나타내었다. 주기성은 섬유간 거리와 이온 속도를 이용하여 설명할 수 있었다.