• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.153-157
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• 2017

Gel type internal electrolytes were synthesized by varying hydroxyethyl-cellulose (HEC) amounts and their durability and conductivity were measured. The ionic conductivity decreased as the content of HEC increased thus the internal electrolyte containing more than 12% of HEC could not be used as a reference electrode. Based on durability test results, as the HEC amount decreased carrier density resulting in increasing of the amount of KCl coming out of the porous membrane. Therefore in order to use long time at ballast water treatment systems, we selected 10% HEC for gel type internal electrolyte. The resolution test for total residual oxidants (TRO) was carried out using the TRO sensor and the gel type reference electrode made of 10% HEC. A 50 mV potential was applied to the TRO sensor for 30 sec and changes in the current were measured. It was confirmed that the TRO concentrations ranging from 0 to 15 mg/L could be separated at salinity conditions of 0.2~30 PSU. The results indicated that the TRO concentration at sea water and at fresh water was successfully measured by the TRO sensor constructed with the reference electrode using gel-type internal electrolyte of HEC.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.3.1-3.1
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• 2011

Nanoengineered materials with advanced architectures are critical building blocks to modulate conventional material properties or amplify interface behavior for enhanced device performance. While several techniques exist for creating one dimensional heterostructures, electrospinning has emerged as a versatile, scalable, and cost-effective method to synthesize ultra-long nanofibers with controlled diameter (a few nanometres to several micrometres) and composition. In addition, different morphologies (e.g., nano-webs, beaded or smooth cylindrical fibers, and nanoribbons) and structures (e.g., core-.shell, hollow, branched, helical and porous structures) can be readily obtained by controlling different processing parameters. Although various nanofibers including polymers, carbon, ceramics and metals have been synthesized using direct electrospinning or through post-spinning processes, limited works were reported on the compound semiconducting nanofibers because of incompatibility of precursors. In this work, we combined electrospinning and galvanic displacement reaction to demonstrate cost-effective high throughput fabrication of ultra-long hollow semiconducting chalcogen and chalcogenide nanofibers. This procedure exploits electrospinning to fabricate ultra-long sacrificial nanofibers with controlled dimensions, morphology, and crystal structures, providing a large material database to tune electrode potentials, thereby imparting control over the composition and shape of the nanostructures that evolved during galvanic displacement reaction.

• Carbon letters
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• v.4 no.2
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• pp.64-68
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• 2003

A study on the electrosorption of uranium ions onto a porous activated carbon fiber (ACF) was performed to treat uraniumcontaining lagoon sludge. The result of the continuous flow-through cell electrosorption experiments showed that the applied negative potential increased the adsorption kinetics and capacity in comparison to the open-circuit potential (OCP) adsorption for uranium ions. Effective U(VI) removal is accomplished when a negative potential is applied to the activated carbon fiber (ACF) electrode. For a feed concentration of 100 mg/L, the concentration of U(VI) in the cell effluent is reduced to less than 1 mg/L. The selective removal of uranium ions from electrolyte was possible by the electrosorption process.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.854-856
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• 1992

The molten carbonate fuel cell has conspicuous features and high potential in being used as an energy converter of various fuels to electricity and heat. However, the MCFC which use strongly corrosive molten carbonate at 650 [$^{\circ}C$] have many problems. This study has examined fabricating methods and specimen characteristics of porous anode electrode.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.214.2-214.2
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• 2011

In this work, porous carbon based electrodes are prepared by carbonization using poly(vinylidene fluoride) (PVDF)/carbon nanotube (CNT) composites to further increase the specific capacitance for supercapacitors. Electrode materials investigate the aspects of specific capacitance, pore size distribution and surface area: influence of carbonization temperatures of PVDF/CNT composites. The electrochemical properties are investigated by cyclic voltammetry, impedance spectra, and galvanostatic charge-discharge performance with in $TEABF_4$ (tetraethylammonium tetrafluoroborate)/acetonitrile as non-aqueous electrolyte. From the results, the highest value of specific capacitance of ~101 $F{\cdot}g^{-1}$ is obtained for the samples carbonized at $600^{\circ}C$. Furthermore, pore size of samples control be low 7 nm through carbonization process. It is suggested that micropores significantly contribute to the specific capacitance, resulting from improved charge transfer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.240-240
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• 2010

In this paper, in these case of photoelectrode using UV treatment after oxygen solar conversion efficiency is increased. According to oxygen injection UV treatment will removal residual organics and increase the TiO2 surface area but also UV treatment can affect the same chemical action of ozone treatment. More porous networks and larger porosities were obtained in the TiO2 films prepared UV treatment after oxygen injection.

• Journal of Energy Engineering
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• v.2 no.2
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• pp.187-193
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• 1993

Porous matrices to contain and support phosphoric acid were prepared with PTFE as binder and SiC whisker or SiC powders of various particle size for phosphoric acid fuel cell(PAFC). Among the matrix characteristics the most important factors in stack performances were thought to be the bubble pressure and electrolyte wettability And then matrix was constructed to have pore size smaller than that of electrode. The bubble pressures and wettabilities of matrices manufactured with various size of SiC and different PTFE contents were investigated and related with the porosities measured by porosimeter, and then the optimum manufacturing condition of matrix for PAFC was determined.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.485.1-485.1
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• 2014

In this research, we report the synthesis of three-dimensional (3D) hierarchical porous graphene aerogels (hpGAs) for application to electrochemical energy storage. For electrochemical systems, the specific capacitance is a key parameter to evaluate the characteristics of electrode materials. By taking full advantage of large surface area, 3D hpGAs would achieve the larger specific capacitance over rGO film and GAs. Microscopic structures and topologies of hpGAs were investigated using field emission scanning electron microscopy and transmission electron microscopy. X-ray photoelectron spectroscopy was used to determine the chemical compositions of rGO film, GAs, and hpGAs. Raman spectra were recorded from 100 to 2500 cm-1 at room temperature using a Raman spectroscopy equipped with a ${\times}100$ objective was used. The specific area and pore distribution of GAs and hpGAs were obtained using a Brunauer-Emmett-Teller apparatus.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.305-305
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• 2009

The carbon nano-structured materials could be applied to the fields of advanced fillers, templates, electrode materials, sensor, storage, and absorption materials. The polyacrylonitrile (PAN) based carbon nano-particles provide the remarkable properties of high specific surface area, large pore volume, chemical inertness, and good mechanical stability. In this study, well-defined carbon nano-particles were obtained through pyrolysis of polyacrylonitrile based particles. The precursor nano-particles were prepared by modified aqueous dispersion polymerization using hydrophilic poly(vinyl alcohol) in a water/ N,N-dimethylformamide mixture media. Synthesized precursor nanoparticles have relatively monodisperse particles ranging 80 ~ 250nm. Stable spherical particles are obtained without coagulum or secondary particles in our system. The characteristic of the carbon nanoparticles were investigated in terms of surface area, morphology, and size distribution.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.270-271
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• 2014

리튬공기전지 및 연료전지의 고용량, 고효율 특성을 달성하기 위해서는 이들 전지를 구성하는 탄소전극물질의 pore구조가 매우 중요 하다. 이에 본 연구에서는 솔루션 플라즈마라는 새로운 공정을 이용하여 micro-pore비율이 극히 적고, meso-pore 중심으로 구성되어 있는 새로운 구조체의 합성에 성공하였고, 실제 리튬공기전지를 제작하여 방전시험을 한 결과, 기존 상업용 탄소재료보다 30~40% 이상의 우수한 고용량을 나타내는 것을 확인 할 수 있었다.