• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.199-205
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• 1999

The electrochemical properties of PAN-PVDF-PEGME blend polymer electrolyte system are investigated and the physical properties are also measured with varying the content of PEGME. This PEGME partially reduces the crystallinity of PVDF. The ionic conductivities of the polymer electrolytes are about $10^{-3}S/cm$, which may be applicable to a constituent of lithium secondary battery. From the temperature dependence of ionic conductivity, it is suggested that the ionic conductivity increases with the PEGME content due to the fomation of effective ion-conducting path. The cation transference number reaches its maximum value for the electrolytes (SPE 2) with 10 wt% PEGME and then decreases for further increase of PEGME contnet. The electrochemically stable range of SPE 1 (without PEGME) is about 4.3 V, but SPE 2-4 (PAN-PVDF-PEGME system) is about 4.6 V. When these polymer electrolyte are used as electrolyte in rechargeable battery and the cell performances are tested, the discharge capacity increses with the amount of PEGME. Therefore, PEGME increases the ionic conductivity, extends the electrochemical stable range, and finally improves the discharge capacity of cell adopting the electrolyte system.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.265-265
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• 2015

Zinc Oxide 층은 역구조 유기 태양전지(Inverted Organic Photovoltaics, IOPV)에서 전자 수집 층으로 사용되는데, 전자 수집 및 전기 전도도 증가를 위하여 일반적으로 3차원 나노 구조체 및 양이온이 도핑된 Zinc Oxide 층이 사용된다. 본 연구에서는 저온 3차원 나노 구조체 및 음이온이 도핑된 Zinc Oxide 층을 적용하였으며, 그 결과 전자 수집 향상, 전기 전도도의 증가에 의하여 광전변환 효율(Power Conversion Efficiency, PCE)이 향상됨을 확인할 수 있었다.

• KCID journal
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• v.13 no.1
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• pp.91-100
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• 2006

• Membrane Journal
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• v.22 no.4
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• pp.265-271
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• 2012

Polybenzimidazole (PBI) was prepared by condensation polymerization using diaminobenzidine (DAB) and isophtalic acid (IPAc). The cation exchange membrane was prepared by introduce the ion exchange group in the PBI polymer. It was confirmed from FT-IR analysis that the prepared PBI powder had same peak compared with commercial PBI power. The ionic conductivity of PBI film was $0.1{\sim}0.9{\times}10^{-2}$ S/cm. The ionic conductivity of prepared SPBI cation exchange membrane showed $3.7{\sim}4.7{\times}10^{-2}$ S/cm and had higher than Nafion117 ($2.0{\times}10^{-2}$ S/cm).

• Membrane Journal
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• v.14 no.1
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• pp.44-52
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• 2004

This paper concerns the development of a cationic polymeric membranes for direct methanol fuel cell. The crosslinked poly(vinyl alcohol) (PVA) membranes with poly(acrylic acid-co-maleic acid) (PAM) and hydroquinonesulfonic acid (HQSA) as the crosslinking agents were prepared according to the amount of crosslinking agents. The resulting membranes were characterized in terms of methanol permeability, proton conductivity, water content and ion exchange capacity. The methanol permeability and proton conductivity increased with increasing PAM content up to 9 wt% and then decreased. This trend is considered the effect of the cross linking rather than the introduction of hydrophilic groups. When the HQSA contents were varied, no interesting increases of proton conductivity, water content and ion exchange capacity were found.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.593-597
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• 2016

The effects of relative humidity, current density and temperature on the ionic conductivity were studied in PEMFC (Proton Exchange Membrane Fuel Cell). Water contents and water flux in the electrolyte membrane largely affected ion conductivity. The water flux was modelled and simulated by only electro-osmotic drag and back-diffusion of water. Ion conductivities were measured at membrane state out of cell and measured at MEA (Membrane and Electrode Assembly) state in condition of operation. The water contents in membrane increase as relative humidity increased in PEMFC, as a results of which ion conductivity increased. Current enhanced electro-osmotic drag and back diffusion and then water contents linearly increased. Enhancement of current density results in ion conductivity. Ion conductivity of about 40% increased as the temperature increased from $50^{\circ}C$ to $80^{\circ}C$.

• Polymer(Korea)
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• v.34 no.2
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• pp.126-132
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• 2010

A cation-exchange nanofiber poly(vinylidene fluoride) (PVdF) membrane was prepared by a radiation-induced graft polymerization (RIGP) of sodium styrene sulfonate (NaSS) in the presence of the polymerizable access agents in methanol solution. The used polymerizable access agents include styrene, acrylic acid, and vinyl pyrrolidone. The anion-exchange nanofiber PVdF membrane was also prepared by RIGP of glycidyl methacrylate (GMA) and its subsequent chemical modification. The successful preparations of cation- and anion-exchange PVdF membranes were confirmed via SEM, XPS and thermal analysis. The content of the grafting yield, ion-exchange group, and water uptake was in the range of 30.0~32.3%, 2.81~3.01 mmol/g and 66.6~147%, respectively. The proton conductivity at 20$^{\circ}C$ was in the range of 0.020~0.053 S/cm. From the result, the prepared ionexchange PVdF membrane can be used as a separator in battery cells.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.465-470
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• 2017

Sulfonated fluorinated block copolymers having diphenyl units were mixed with the sulfonated cationic conductive polymers at an optimum mixing ratio to form hybrid membranes for fuel cells and their characteristics were studied. 2D and 3D AFM topology analysis confirmed that the number of hydrophilic units in the hybrid membrane was improved. Through the FE-SEM, the microstructure of the hybrid membrane implied hydrogen bonding and pi-pi interactions, and EDAX confirmed carbon, oxygen, sulfur, and fluorine. The thermogravimetric analysis showed that the hybrid membrane was thermally stable and the hydrophilicity of the hybrid membrane was increased by the contact angle of water droplets. As a result, it was confirmed that the cation conductivity increased by a factor of 1.8 times as the number of acidic domains in the hybrid film increased.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.1-8
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• 2014

Ion exchange membrane is widely used in various fields such as electro dialysis, diffusion dialysis, redox flow battery, fuel cell. PVC cation exchange membrane using ultrasonic modification was prepared by sulfonation reaction in various sulfonation times. Sulfuric acid was used as a sulfonating agent with ultrasonic condition. We've characterized basic structure of sulfonated PVC cation exchange membrane by FT-IR, EDX, water uptake, ion exchange capacity (IEC), electrical resistance (ER), conductivity, ion transport number and surface morphology (SEM). The presence of sulfonic groups in the sulfonated PVC cation exchange membrane was confirmed by FT-IR. The maximum values of water uptake, IEC, electrical resistance and ion transport number were 40.2%, 0.87 meq/g, $35.2{\Omega}{\cdot}cm^2$ and 0.88, respectively.

• Journal of the Korean Ceramic Society
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• v.38 no.8
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• pp.698-704
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• 2001

Doped ceria의 전기전도도는 도핑 원소의 종류와 양에 큰 의존성을 가지고 특정 조성에서 최대 전도도 값을 가지며 높은 dopant 농도에서는 전기전도도는 감소한다. 이런 현상은 dopant와 산소 빈자리 사이의 회합 형성과 관련이 있다고 알려져 있다. 그러나 Gd 이온이 도핑된 ceria의 경우 주된 회합종이 (2G $d_{Ce}$ $V_{o}$ )인지 (G $e_{Ce}$ $V_{o}$ ) 인지는 명확하게 알려져 있지 않다. 본 연구에서는 회합분포가 전기전도도에 미치는 영향을 연구하기 위해 결함의 회합종과 분포가 다른 3가지 경우에 대해서 시뮬레이션을 행하였다. 분자동력학법을 이용하여 다양한 온도와 다른 회합분포의 경우에 대해 산소 확산계수가 계산되어졌으며, 계산된 산소 확산계수는 실험적으로 결정된 bulk 전도도로부터 얻어진 산소 확산계수와 비교되어졌다. 그 결과 (2G $d_{Ce}$ $V_{o}$ )와 (G $e_{Ce}$ $V_{o}$ ) 회합이 공존하며 이들이 통계학적으로 이항 분포를 가지는 경우가 실험적으로 보고된 값과 가장 일치하는 결과를 얻을 수 있었다.