• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.99-103
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• 2019

A derivative of 1,4-Naphthoquinone coded HBU671 was synthesized and used in addition to activated carbon as composite electrode for supercapacitor application. From the electrochemical properties analysis, a specific capacitance of about $300F\;g^{-1}$ exhibited almost two times of that of activated carbon at a scan rate of $100mV\;s^{-1}$ and a potential window of - 0.2 - 1V. This improvement is due to the inherent redox reaction in HBU671. Cycle test also proved that this composite is still stable even after 1000 cycle within the applied potential window and it is highly recommended for practical application.

• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.387-397
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• 2021

Deep eutectic solvents have been established as feasible metal electroplating solvent alternatives over traditional toxic aqueous plating baths. However, water, either added intentionally or unintentionally, can significantly influence the solvent's physical properties and performance, thereby hindering its industry application. In this study, the hygroscopicity, or the ability to absorb moisture from the environment, of synthesized ethaline (1:2 choline chloride:ethylene glycol) was investigated. The kinematic viscosity, electrical conductivity, electrochemical window, and water content of ethaline were monitored over a 2-week period. Karl Fischer titration tests showed that ethaline exposed to the atmosphere displayed significant hygroscopicity compared to its unexposed counterpart. ¹H NMR spectroscopy revealed that water vapor was readily absorbed at the surface due to the hydrophilic groups present in the ethaline molecule. Water uptake resulted in the decrease in viscosity, increase in electrical conductivity and narrowing of the electrochemical window of ethaline. Solution heating at 100℃ removed the absorbed moisture and allowed the recovery of the solvent's initial properties.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.15-20
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• 2023

Ionic liquids are considered as a promising, alternative solvent for the electrochemical synthesis of metals because of their high thermal and chemical stability, relatively high ionic conductivity, and wide electrochemical window. In particular, their wide electrochemical window enables the electrodeposition of metals without any side reaction of electrolytes such as hydrogen evolution. The electrodeposition of silver is conducted in 1-n-butyl-3-methylimidazolium chloride ([C4mim]Cl) ionic liquid system with a silver source of AgCl. This study is the first attempt to electrodeposit silver nanoparticles without using co-solvents other than [C4mim]Cl. Pulse electrolysis is employed for the synthesis of silver nanoparticles by varying applied potentials from -3.0 V to -4.5 V (vs. Pt-quasi reference electrode) and pulse duration from 0.1 s to 0.7 s. Accordingly, the silver nanoparticles whose size ranges from 15 nm to ~100 nm are obtained. The successful preparation of silver nanoparticles is demonstrated regardless of the kinds of substrate including aluminum, stainless steel, and carbon paper in the pulse electrolysis. Finally, the antimicrobial property of electrodeposited silver nanoparticles is confirmed by an antimicrobial test using Staphylococcus aureus.

• Bulletin of the Korean Chemical Society
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• 제19권1호
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• pp.107-109
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• 1998

The $SnO_2$, Sn-doped $In_2O+3\; and \;Ce-doped\; TiO_2$ films have been prepared by RF sputtering method, and their opto-electrochemical properties were investigated in view of the applicability as counter electrodes in the electrochromic window system. These oxide films could reversibly intercalate $Li^+$ ions owing to the nanocrystalline texture, but remained colorless and transparent. The high transmittance of the lithiated films could be attributed to the prevalence of the $Sn^{4+}/Sn^{2+}\; and\; Ce^{4+}/Ce^{3+}$ redox couples having 5s and 6s character conduction bands, respectively. For the Ce-doped $TiO_2$ film, $(TiO_2)_{1-x}(CeO_2)_x$, an optimized electrochemical reversibility was found in the film with the composition of x = 0.1.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2001년도 춘계총회 및 학술발표회
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• pp.34-34
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• 2001

• 전기화학회지
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• 제14권4호
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• pp.225-230
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• 2011

Copper indium gallium selenide (CIGS) 기반 박막 태양전지는 저렴한 제작 단가 및 다른 박막 태양전지에 비해 높은 효율을 보여 실리콘 기반 태양전지의 차세대 태양전지로 각광을 받고 있다. 구성 요소 중 buffer 층은 window 층과 absorber 층 사이의 높은 밴드 갭(band gap)을 해소 해주는 역할을 한다. 기존의 cadmium sulfide(CdS)의 인체 유해성 때문에 이를 대신할 indium sulfide(In2S3)를 이용한 buffer 층의 연구가 활발히 진행되고 있다. 본 연구에서는 전기화학적인 방법을 통해 값싸고 간편하게 indium sulfide buffer 층을 전극 표면에 합성하는 연구를 진행하였다. Indium-Tin-Oxide(ITO) 전극표면을 sodium thiosulfate 및 indium sulfate의 혼합물 용액에 담그고 환원 전위를 인가하여 indium sulfide를 합성하였다. 크기가 다른 두 전압을 교대로 인가하여 확산 한계(diffusion limit)를 최소화 함으로써 표면에 균일한 조성을 가지는 buffer 층을 합성해 낼 수 있었다. 또한 합성 중 온도의 조절을 통해 buffer 층의 밴드 갭을 최적화 할 수 있었다. 이렇게 전기화학적으로 합성된 buffer 층은 X-선 광전자 분광법과 회절법의 분석을 통해 ${\beta}$-indium sulfide 결정구조를 가짐을 확인 하였다.

• 전기화학회지
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• 제9권2호
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• pp.59-63
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• 2006

전해코팅 법과 dip-coating 법을 이용해 산화주석(IV)을 티타늄 지지체에 코팅하여, 코팅 방법에 따른 코팅 전극의 물성과 전기화학적 특성에 대해여 연구하였다. HCl 로 전극 에칭 후, nitrate 용액에 $SnCl_2{\cdot}2H_2O$을 용해시켜 pulse technique를 이용하여 전해코팅 하였으며, dip-coating 법 또한 $SnCl_2{\cdot}2H_2O$를 사용하여 1:1V% HCl 용액에 용해시켜 코팅 소결 후 산화주석(IV)코팅 전극을 제작하였다. 두 가지 코팅 방법을 통해 제작된 산화주석(IV)코팅 전극은 전극의 물성을 비교하기 위해 x-ray diffraction (XRD), scanning election microscopy (SEM)를 관찰해보았고, 전기화학적 특성을 평가하기 위해 cyclic voltammetry (CV)를 측정하여 전위창을 비교해 보았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.346.1-346.1
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• 2014

Porous nano crystalline $TiO_2$ is currently used as a working electrode in a dye-sensitized solar cell (DSSC). The conventional working electrode is comprised of absorption layer (particle size:~20 nm) and scattering layer (particle size:~300 nm). We inserted window layer with 10 nm particle size in order to increase transmittance and specific surface area of $TiO_2$. The electrochemical impedance spectroscope analysis was conducted to analysis characterization of the electronic behavior. The Bode phase plot and Nyquist plot were interpreted to confirm the internal resistance caused by the insertion of window layer and carrier lifetime. The photocurrent that occurred in working electrode, which is caused by rise in specific surface area, increased. Accordingly, it was found that insertion of window layer in the working electrode lead to not only effectively transmitting the light, but also increasing of specific surface area. Therefore, it was concluded that insertion of window layer contributes to high conversion efficiency of DSSCs.

• 전기화학회지
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• 제6권3호
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• pp.169-173
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• 2003

금속산화물 전극을 이용한 전기화학 캐패시터는 일반적으로 산성 수용액 전해질에서 금속산화물에 대한 양성자의 가역적인 전기화학반응을 이용한다. 수계 전해질을. 사용한 수퍼캐패시터는 전위창(electrochemical stability window)이 유기계 전해질을 사용한 수퍼캐패시터에 비해 좁은 문제를 안고 있다. 금속산화물 전극과 리튬 또는 암모늄 이온을 함유한 유기계 전해질을 사용한 전기화학 캐패시터의 특성을 확인하였다. $RuO_2$ 전극을 사용한 전기화학 캐패시터는 1M $LiPF_6$, EC, DEC 및 EMC혼합용매 전해액 중에서 순환전위전류법(주사속도. 2mV/sec, 전위영역: $2.0\~4.2V(Li|Li^+))$으로 산화 및 환원에 대하여 비정전용량을 구한 바, 각각 145 및 $142F/g-RuO_2{\cdot}nH_2O$이었다

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1125-1128
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• 2002

Electrochemical capacitor made with metal oxide electrode uses rapid and reversible protonation/deprotonation of metal oxide material under the aqueous acidic solution, generally. Electrochemical stability window of aqueous electrolyte-type capacitor is narrow compared to that of organic electrolyte-type capacitor. Electrochemical characteristics of electrochemical capacitor made with metal oxide electrode and lithium cation based organic electrolyte were evaluated. Electrochemical capacitor based on $RuO_2$ electrode material and 1M $LiPF_6$ in mixed solvents of EC, DEC, and EMC has anodic and cathodic specific capacitance of 145 and 142 F/g-$RuO_2{\cdot}nH_2O$, respectively, by using cyclic voltammetry with scan rate of 2 mV/sec g-$RuO_2$ in potential range of 2.0~4.2V(Li|$Li^+$).