• 마이크로전자및패키징학회지
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• 제22권1호
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• pp.55-61
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• 2015

신축성 전극소재는 웨어러블 밴드나 전자피부와 같은 플렉서블 제품으로의 적용 때문에 주목 받고 있다. 플렉서블 소자로서 사용하기 위해선 구부리거나 비틀거나 늘리는 등 물리적 변형에도 전기저항의 증가가 최소화되어야 한다. 카본블랙은 저가의 간단한 공정, 특히 인장 시 비저항의 감소라는 장점 때문에 후보소재로 고려되고 있다. 하지만 카본블랙의 전도도는 전극으로 사용되기에 상대적으로 낮다. 이에 비해 그래핀은 뛰어난 전기전도도 및 유연성 때문에 촉망받고 있는 전자소재이다. 따라서 그래핀을 첨가한 카본블랙은 신축성 전극으로 적합한 소재로 예상된다. 본 논문을 통해 인장 시 그래핀을 첨가한 카본전극의 전기적 특성을 연구하였다. 기계적인 인장은 전극 내의 균열(crack)을 형성시켜 도전경로의 파괴를 일으켰다. 하지만 인장으로 정렬된 그래핀은 카본필러 간의 연결성을 강화하고 도전구조를 유지하였다. 무엇보다도 그래핀 첨가로 인하여 인장 시 카본전극의 전자구조가 변화하여 전자를 효과적으로 전도하게 하였다. 결론적으로 그래핀 첨가를 통해 카본블랙 복합체에 신축성 전극으로의 가능성을 부여하였다.

• Corrosion Science and Technology
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• 제20권4호
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• pp.183-188
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• 2021

The increasing demand for energy storage in mobile electronic devices and electric vehicles has emphasized the importance of electrochemical energy storage devices such as Li-ion batteries (LIBs) and supercapacitors. For reversible Li storage, alternative anode materials are actively being developed. In this study, we designed and fabricated an Nb₂O₅-Li₃VO₄ composite for use as an anode material in LIBs and hybrid supercapacitors. Nb₂O₅ powders were dissolved into a solution and the precursors were precipitated onto Li₃VO₄ through a simple, low-temperature hydrothermal reaction. The annealing process yielded an Nb₂O₅-Li₃VO₄ composite that was characterized by X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy. Electrochemical tests revealed that the Nb₂O₅-Li₃VO₄ composite electrode demonstrated increased capacities of approximately 350 and 140 mAh g^-1 at 0.1 and 5 C, respectively, were maintained up to 1000 cycles. The reversible capacity and rate capability of the composite electrode were enhanced compared to those of pure Nb₂O₅-based electrodes. These results can be attributed to the microstructure design of the synthesized composite material.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.966-970
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• 2006

We reported on characteristics of the piezoelectric ceramic-polymer composite for the application of the thick-film speaker. The PVDF-PZT composites were fabricated to incorporate the advantages of both ceramic and polymer with various mixing ratios by 3-roll mill mixer. The composite solutions were coated by the conventional screen-printing method on ITO electrode coated PET (Polyethylene terephthalate) polymer film. After depositing the top-electrode of silver-paste, 4 kV/mm of DC field was applied at $120^{\circ}C$ for 30 min to poling the composite films. The value of $d_{33}$ (piezoelectric charge constant) was increased when the PZT weight percent was increased. The maximum value of the $d_{33}$ was 24 pC/N at 70 wt% PZT. But the $g{33}$ (piezoelectric voltage constant) showed the maximum value of $32mV{\cdot}m/N$ at 65 wt% of PZT powder. The SPL (sound pressure level) of the speaker fabricated with the 65:35 composite film was about 68 dB at 1 kHz.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.694-704
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• 2018

Novel $SnO_2$ mixed biochar composite was prepared from banana peel developed as electrode material for supercapacitor using simple chemical co-precipitation method. The physiochemical and morphological properties of activated composite $SnO_2$ mixed biochar were investigated with XRD, FTIR, UV-vis, FESEM and HRTEM. The composite accounts for outstanding electrochemical behavior such as high specific capacitance, significant rate capability and leading to good cycle retention up to 3500 cycles when used as electrode material for supercapacitors. Highly permeable $SnO_2$ mixed biochar derived from banana peel exhibited maximum specific capacitance of $465F\;g^{-1}$ at a scan rate of $10mV\;s^{-1}$ by cyclic voltammetry (CV) and $476Fg^{-1}$ at current density of $0.15Ag^{-1}$ by charge discharge studies significantly higher about 47% than previously reported identical work on banana peel biochar.

• 한국세라믹학회지
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• 제45권8호
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• pp.493-496
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• 2008

Composite electrodes consisting of $CoMnO_2$ and carbon nanofibers(vapor grown carbon nanofiber, VGCF) with high electrical conducivity($CoMnO_2$/VGCF) were prepared on a porous nickel foam substrate as a current collector and their supercapacitive properties were investigated using cyclic voltammetry in 1 M KOH aqueous solution. The $CoMnO_2$/VGCF electrode exhibited high specific capacitance value of 630 F/g at 5 mV/s and excellent capacitance retention of 95% after $10^4$ cycles, indicating that the used VGCF played the important roles in reducing the interfacial resistance in the composite electrode to improve supercapacitive performance.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권2호
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• pp.61-67
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• 2006

Dielectric and conductive frequency spectra in 0.01 Hz-13 MHz range have been measured for the composite consisting of PZT inclusions dispersed in $LiCIO_{4}$-doped polyerhylene oxide(Li_PEO) matrix with various volume fractions. The dielectric and conductive spectra of the composites revealed the relaxations related with electrode polarization and interfacial polarization. The observed spectra were reproduced using the empirical dielectric function and we could obtain various parameters related to the above two kinds of polarizations and dicussed about the parameters.

• Advances in Energy Research
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• 제3권1호
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• pp.45-57
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• 2015

This article is addressed to define a new composite electrode constituted by porous nickel and an array of highly ordered $TiO_2$ nanotubes obtained by a previous galvanostatic anodization treatment in an ethylene glycol solution. The electrochemical performances of the composite anode were evaluated in a photo-electrolyser, which showed good solar conversion efficiency with respect to the UV irradiance together with a reduction of energy consumption. Such a combination of materials makes our system simple and able to work both in dark and under solar light exposure, thus opening new perspectives for industrial-scale applications.

• 세라미스트
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• 제22권2호
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• pp.170-181
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• 2019

All-solid-state batteries have received increasing attention because of their high safety aspect and high energy and power densities. However, the inferior solid-solid interfaces between solid electrolyte and active materials in electrode, which cause high interfacial resistance, reduce ion and electron transfer rate and limit battery performance. Recently, spark plasma sintering is emerging as a promising technique for fabricating solid electrolytes and composite-electrodes. Herein, this paper focuses on the overview of spark plasma sintering to fabricate solid electrolytes and composite-electrodes for all-solid-state batteries. In the end, future opportunities and challenges associated with SPS technique for all-solid-state batteries are described.

• 공업화학
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• 제24권1호
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• pp.49-54
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• 2013

혼합용액에서 nitrate 이온을 선택적으로 제거하기 위해 복합탄소전극을 제조하였다. 질산이온 선택성 수지(BHP55, Bonlite Co.) 분말을 탄소전극 표면에 코팅하여 전극을 제조하였다. 제조한 전극으로 BHP55 셀을 제작하여 chloride, nitrate, sulfate 이온이 혼합된 용액에 대해 축전식 탈염 실험을 수행하였다. 그리고 BHP55 셀에서의 질산 이온 제거량을 이온교환막을 결합한 MCDI 셀의 결과와 비교하였다. BHP55 셀에서 이온의 총 흡착량은 MCDI 셀에서 보다 31% 증가한 $38.3meq/m^2$를 나타냈다. 또한 BHP55 셀에서 질산 이온의 흡착량은 $15.9meq/m^2$ (전체 흡착량의 42%)이었고, 이는 MCDI 셀에서 보다 2.1배 큰 것으로 나타났다. 실험결과 제조한 복합탄소전극은 음이온 혼합용액에서 질산 이온을 선택적으로 제거하는데 매우 효과적임을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1755-1762
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• 2013

A graphene-Zn/Al layered double hydroxide composite film was simultaneously prepared by electrochemical deposition on the surface of a glassy carbon electrode (G-LDH/GCE) from the mixture solution containing GO and nitrate salts of $Zn^{2+}$ and $Al^{3+}$. The modified electrode showed good electrochemical performances toward the simultaneous electrochemical detection of hydroquinone (HQ), catechol (CA) and resorcinol (RE) due to the unique properties of graphene (G) and LDH such as large active surface area, facile electronic transport and high electrocatalytic activity. The redox characteristics of G-LDH/GCE were investigated with cyclic voltammetry and differential pulse voltammetry. The well-separated oxidation peak potentials, corresponding to the oxidation of HQ, CA and RE, were observed at 0.126 V, 0.228 V and 0.620 V respectively. The amperometric response of the modified electrode exhibited that HQ can be detected without interference of CA and RE. Under the optimized conditions, the oxidation peak current of HQ is linear with the concentration of HQ from 6.0 ${\mu}M$ to 325.0 ${\mu}M$ with the detection limit of 0.077 ${\mu}M$ (S/N=3). The modified electrode was successfully applied to the direct determination of HQ in a local tap water, showing reliable recovery data.