• 산업기술연구
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• 제20권A호
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• pp.185-194
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• 2000

In this work we measured the total pressure of the aqueous solutions and the methanol-water solutions dissolved with inorganic salts, at $25^{\circ}C$. In organic electrolytes used in this work were $K_2SO_4$ and $(NH_4)_2SO_4$. Using the measured vapour pressures the activity coefficient of solvents and the mean ionic activity coefficient were obtained through thermodynamic relations. The activity coefficients of solvent and the mean ionic activity coefficirnt obtained in this work were fitted with Macedo's model and Acard's model. Both two models were good agreeable to the vapor pressure and the mean ionic activity coefficient for the electroyte aqueous solutions. For electrolyte /methanol/water solutions, Macedo's model had much deviation from experimental data, while Acard's model showed a good agreement with experimental data.

• Carbon letters
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• 제1권3_4호
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• pp.133-137
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• 2001

Mesoporous activated carbon fiber (ACF) was prepared from phenolic resin containing a small amount (0.1 wt %) of organic nickel complex through carbonization and steam activation. Microporous ACF as reference sample was also prepared from phenolic resin without agent. In both cases of the mesoporous ACFs and the microporous ACFs, the electric double layer capacitance of the nonaqueous electrolyte (0.5 M $TEABF_4$/PC or 1.0 M $LiClO_4$/PC) was not proportional to the BET specific surface area. This is owing to the low permeability of nonaqueous electrolyte or the low mobility of ion in narrow micropores. However, the mesoporous ACF showed higher double layer capacitance than the microporous (normal) ACF. This result suggests that the presence of many mesopores promotes the formation of effective double layer or the transfer of ion in the micropore.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.605-608
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• 2011

Hybrid composite membranes were prepared by coating poly(ethylene oxide) and $SiO_2$ particles onto the porous polypropylene nonwoven matrix. Gel polymer electrolytes prepared by soaking the hybrid composite membranes in an organic electrolyte solution exhibited ionic conductivities higher than $1.1{\times}10^{-3}Scm^{-1}$ at room temperature. Dyesensitized solar cell (DSSC) employing the hybrid composite membrane with PEO and 10 wt % $SiO_2$ exhibited an open circuit voltage of 0.77 V and a short circuit current of 10.78 $mAcm^{-2}$ at an incident light intensity of 100 $mWcm^{-2}$, yielding a conversion efficiency of 5.2%. DSSC employing the hybrid composite membrane showed more stable photovoltaic performance than that of the DSSC assembled with liquid electrolyte.

• 공업화학
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• 제30권6호
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• pp.643-651
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• 2019

Polybenzimidazole (PBI), an engineering polymer with well-known excellent thermal, chemical and mechanical stabilities has been recognized as an alternative to high temperature polymer electrolyte membranes (HT-PEMs). This review focuses on recent advances made on the development of PBI-based HT-PEMs for fuel cell applications. PBI-based membranes discussed were prepared by various strategies such as structural modification, cross-linking, blending and organic-inorganic composites. In addition, intriguing properties of the PBI-based membranes as well as their fuel cell performances were highligted.

• 전기화학회지
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• 제5권4호
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• pp.192-196
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• 2002

Ionic liquids based on l-ethyl-3-methylimidazolium cation $(EMI^+)$ and inorganic or organic anions containing fluorine atoms were applied to electrolyte materials for double-layer capacitors. The double-layer capacitors composed of a pair of activated carbon electrodes and an ionic liquid selected from $EMIBF_4,\; EMINbF_6,\;EMITaF_6,\;EMICF_3SO_3,\;EMI(CF_3SO_2)_2N,\;and\;EMI(C_2F_5SO_2)_2N$ showed inferior low-temperature characteristics to those of a conventional nonaqueous electrolyte based on propylene carbonate (PC) solvent. On the other hand, the capacitor using $EMIF{\cdot}2.3HF$ showed excellent low-temperature characteristics due to its high conductivity at low temperatures, however, it had a lower working voltage $(\~2V)$ than the conventional nonaqueous counterpart $(\~3V)$.

• 멤브레인
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• 제29권3호
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• pp.164-172
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• 2019

본 연구에서는 녹말(starch)과 poly(acrylonitrile) (PAN)으로 이루어진 가지형 공중합체 기반의 슈퍼 캐퍼시터용 전해질막을 손쉽게 제조하는 방법을 제시하였다. 가지형 공중합체(starch-g-PAN)는 세륨 이온에 의해 개시된 자유 라디칼 중합을 통해 합성되었다. 실온에서 어떠한 유기용매 없이 Starch-g-PAN 고분자를 이온성 액체, 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA)에 용해하였으며 1시간 동안 $100^{\circ}C$의 고온을 가해줌으로써 손쉽게 고분자 막을 만들었다. 제조된 막은 유연하여 플렉서블 고체 슈퍼 캐퍼시터의 전해질에 적용되었다. Starch-g-PAN 기반의 고분자 전해질막을 사용한 슈퍼 캐퍼시터는 0.5 A/g의 전류 밀도에서 약 21 F/g의 정전용량을 가졌으며 10,000 사이클 동안 86%의 유지율을 보이며 높은 주기 안정성을 보였다. 본 연구를 통해 starch-g-PAN 기반의 고분자 전해질막이 우수한 성능을 가진 플렉서블 고체 슈퍼 캐퍼시터에 응용될 수 있음을 확인하였다.

• Carbon letters
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• 제17권1호
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• pp.70-73
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• 2016

• 한국표면공학회지
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• 제19권2호
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• pp.44-50
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• 1986

Effects of cathodic overvoltages on the electrodeposition of lead from electrolyte containing lead chloride, ammonium acetate and sodium succinate was investigated at 20$^{\circ}C$. The use of organic additives, phenol and gelatin was found effective to inhibit the growth of dendritic crystals. At the carthodic overvoltages higher than 0.2V, the lead deposit becames less compact even in the presence of organic additives. The applications of agitation and pulse current promoted compact and shiny deposits.

• 전기화학회지
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• 제17권1호
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• pp.26-29
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• 2014

The corrosion behavior of stainless steel 304 (SS 304), titanium, nickel and aluminium is studied by immersion and anodic polarization tests in non-aqueous electrolytes. Tetraethyl ammonium tetrafluoroborate is used as a supporting electrolyte in the three kinds of solvents. The immersion test shows that chemical corrosion rate in propylene carbonate-based electrolyte is lower than those in acetonitrile- or ${\gamma}$-butyrolactone-based electrolytes. Surface analyses do not reveal any corrosion product formed after the immersion test. In the anodic polarization tests, a higher concentration of supporting electrolyte gives a higher current density. In addition, a higher temperature increases the current density in the active region and reduces the potential range in the passive region. SS 304 shows the highest corrosion potential while Al shows the lowest corrosion potential and the highest current density in all studied conditions. Based on the conducted corrosion tests, the corrosion resistance of metal substrates in the organic solvents can be sorted in descending order as follows: SS 304 - Ti - Ni - Al.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.396-396
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• 2012

$TiO_2$ anatase nanotube arrays (NTAs) were grown by electrochemical anodization and followed annealing of Ti foil. Ethylene glycol/$NH_4F$-based organic electrolyte was used for electrolyte solution and using second anodization process to obtain free-standing NTAs. After obtaining NTAs, ITO film was deposited by sputtering process on bottom of NTAs. UV-curable NOA was used for attach free-standing NTAs on flexible plastic substrate (PEN). Solid state electrolyte (spiro-OMeTAD) was coated via spin-coating method on top of attached NTAs. Ag was deposited as a counter electrode. Under AM 1.5 simulated sunlight, optical characteristics of devices were investigated. In order to use flexible polymer substrate, processes have to be conducted at low temperature. In case of $TiO_2$ nano particles (NPs), however, crystallization of NPs at high temperature above $450^{\circ}C$ is required. Because NTAs were conducted high temperature annealing process before NTAs transfer to PEN, it is favorable for using PEN as flexible substrate. Fabricated flexible solid-state DSSCs make possible the preventing of liquid electrolyte corrosion and leakage, various application.