• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.261-264
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• 2000

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li polymer battery. This paper describes temperature dependence of conductivity, impedance spectroscopy, electrochemical properties of PAN/PVDF electrolytes as a function of a mixed ratio. PAN/PVDF based polymer electrolyte films were prepared by thermal gellification method of preweighed PAN/PVDF, plasticizer and Li salt. By adding PVDF and as a function of plasticizer mixed ratio to PAN-LiClO4 electrolyte, its conductivity was higher than that of PAN-$LiClO4_4$ electrolyte. The conductivity of PAN/PVDF electrolytes was $10^{-3}S/cm$. $10PAN10PVDFLiClO_4PC_5EC_5$ electrolyte shows the better conductivity of the others. Steady state current method and ac impedance used for the determination of transference numbers in PAN/PVDF electrolyte film. The transference number of $10PAN10PVDFLiClO_4PC_5EC_5$ electrolyte is 0.45.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.121-124
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• 1998

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. This paper describes temperature dependence of conductivity, impedance spectroscopy, electrochemical properties of PVDF electrolytes as a function of a mixed ratio. Polyvinylidene(PVDF) based polymer electrolyte films were prepared by thermal gellification method of preweighed PVDF, plasticizer and Li salt. The conductivity of PVDF electrolytes was 10$\^$-3/S/cm. 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$ electrolyte shows the better conductivity of the others. 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$electrolyte remains stable up to 4.7V vs. Li/Li$\^$+/. Steady state current method and ac impedance used for the determination of transference numbers in PVDFD electrolyte film. The transference number of 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$electrolyte is 0.58.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.487-494
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• 1995

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. We investigated the effects of lithium salts, plasticizer addition, temperature dependence of conductivity and electrochemical stability window of polyethylene oxide(PEO) electrolytes. PEO electrolyte completed with LiCIO$\_$4/ shows the better conductivity than the others. PEO-LiCIO$\_$4/ electrolyte, when EO/Li$\^$+/ ratio is 8, showed adequate conductivity around room temperature. By adding propylene carbonate and ethylene carbonate to PEO-LiCIO$\_$4/ electrolyte, its conductivity was higher than that of PEO-LiCIO$\_$4/ without those. Also PEO$\_$8/LiCIO$\_$4/ electrolyte remains stable up to 4.5V vs. Li/Li.

• Membrane Journal
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• v.32 no.6
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• pp.427-441
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• 2022

Polymer electrolyte membrane (PEM) serving as a separator that can prevent the permeation of unreacted fuels as well as an electrolyte that selectively transports protons from the anode to the cathode has been considered a key component of polymer electrolyte membrane fuel cell (PEMFC). The perfluorinated sulfonic acid-based PEMs, represented by Nafion®, have been commercialized in PEMFC systems due to their high proton conductivity and chemical stability. Nevertheless, these PEMs have several inherent drawbacks including high manufacturing costs by the complex synthetic processes and environmental problems caused by producing the toxic gases. Although numerous studies are underway to address these drawbacks including the development of sulfonated hydrocarbon polymer-based PEMs (SHP-PEMs), which can easily control the polymer structures, further improvement of PEM performances and durability is necessary for practical PEMFC applications. Therefore, this study focused on the various strategies for the development of SHP-PEMs with outstanding performance and durability by 1) introducing cross-linked structures, 2) incorporating organic/inorganic composites, and 3) fabricating reinforced-composite membranes using porous substrates.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.382-382
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• 2009

In this study, we prepared electrodes containing ionic liquid for high temperature polymer electrolyte fuel cells. Effects of ILs on electrochemical properties of the electrodes were investigated carrying out measurement of cyclic voltammograms of the various electrodes with the content of IL in a strong supporting electrolyte. As the ILs content increased in electrodes, electrochemical surface area(ESA) decreased due to the leakage of ILs from Nafion ionomer. In addition, two case of cyclic voltammograms under two simulated environment, i.e. IL leakage from Nafion ionomer in I) electrode and ii) polymer electrolyte, were investigated. As a result, IL leakage from polymer electrolyte showed worse results in electrochemical properties of the electrode.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.295-300
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• 2007

A new characterization method using a porous plug model was proposed to determine the degree of sulfonation (DS) of ionomer binder with respect to the membrane used in membrane-electrode assemblies (MEAs) and to analyze the fraction of proton pathways through ionomer-catalyst combined electrodes in MEAs for polymer electrolyte fuel cells (PEFCs). Sulfonated poly(ether ether ketone) was prepared to use a polymeric electrolyte and laboratory-made SPEEK solution (5wt.%, DMAc based) was added to catalyst slurry to form catalyst layers. In case of the SPEEK-based MEAs in this study, DS of ionomer binder for catalyst layers should be the same or higher than that of the SPEEK membrane used in the MEAs. The porous plug model suggested that most of protons were via the ionomer binder (${\sim}92.5%$) bridging the catalyst surface to the polymeric electrolyte, compared with the pathways through the alternative between the interstitial water on the surface of ionomer binder or catalyst and the ionomer binder (${\sim}7.3%$) and through only the interstitial water on the surface of ionomer or catalyst (${\sim}0.2%$) in the electrode of the MEA comprising of the sulfonated poly(ether ether ketone) membrane and the 5wt.% SPEEK ionomer binder. As a result, it was believed that the majority of proton at both electrodeds moves through ionomer binder until reaching to electrolyte membrane. The porous plug model of the electrodes of MEAs reemphasized the importance of well-optimized structure of ionomer binder and catalyst for fuel cells.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.175-178
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• 2006

Solid-state dye-sensitized solar cells were fabricated using a polymer matrix in electrolyte in the purpose of the improvement of the durability in the dye-sensitized solar cell. In these dye-sensitized solar cells, the polymer electrolyte consisting of $I_2$, LiI, ionic liquid, ethylene carbonate/propylene carbonate and polymer matrix was casted onto $TiO_2$ electrode impregnated Ruthenium complex dye as a photosensitizer. Photovoltaic properties of solid-state dye-sensitized solar cells using polymer matrix (PMMA, PEG, or PAN) were investigated. Comparing photovoltaic effects of cells using hole conducting polymers (BE or 6P) instead of polymer matrix, we investigated the availability of the solid-state polymer electrolyte in dye-sensitized solar cells.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.197-201
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• 2002

In this study, a gel polymer electrolyte was prepared from urethane acrylate and its electrochemical performances were evaluated. And, $LiCoO_2/GPE/graphite$ cells were prepared and their performances depending on discharge currents and temperatures were evaluated. The precursor containing $5 vol\%$ curable mixture had a low viscosity relatively. Ionic conductivity of the gel polymer electrolyte at room temperature and $-20^{\circ}C$ was ca. $5.9\times10^{-3}S{\cdot}cm^{-1}\;and\;1.7\times10^{-3}S{\cdot}cm^{-1}$, respectively. GPE showed electrochemical stability up to potential of 4.5V vs. $Li/Li^+.LiCoO_2/GPE/graphite$ cell showed a good high-rate and a low-temperature performance.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.319-322
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• 2009

Gel polymer electrolytes were prepared by immersing a porous poly(vinylidene fluoride-co-hexafluoropropylene) membrane in an electrolyte solution containing small amounts of polymerizable additive (3,4-ethylenedioxythiophene, thiophene, biphenyl). The organic additives were electrochemically oxidized to form conductive polymer films on the electrode at high potential. With the gel polymer electrolytes containing different organic additive, lithium-ion polymer cells composed of carbon anode and LiCo$O_2$ cathode were assembled and their cycling performances were evaluated. Adding small amounts of thiophene or 3,4-ethylenedioxythiophene to the gel polymer electrolyte was found to reduce the charge transfer resistance in the cell and it thus exhibited less capacity fading and better high rate performance.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.55.1-55.1
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• 2011

Dye-sensitized solar cell(DSSC) have been considered one of the promising alternatives to conventional solar cells, because of their low cost, easy fabrication and relatively high energy conversion efficiency. However, although the cell offers reasonable efficiency at least 11%, the use of a liquid electrolyte placed technological challenges for achieving the desired durability and operational stability of the cell. In order to prevent or reduce electrolyte leakage considerable efforts have been made, such as p-type semiconductor or organic hole-transport material that better mechanical properties and simple fabrication processes. In this work, we synthesized solid-state electrolyte containing LiI and KI metal salt with starting materials of poly ethylene oxide to substitute liquid electrolyte enhance the ionic conductivity and solar conversion efficiency. Li+ leads to faster diffusion and higher efficiency and K+ leading to higher ionic conductivity. The efficiency of poly ethylene oxide/LiI system electrolyte is 1.47% and poly ethylene oxide/potassium electrolyte is 1.21%. An efficiency of 3.24% is achieved using solid-state electrolyte containing LiI and KI concentrations. The increased solar conversion efficiency is attributed to decreased crystallinity in the polymer that leads to enhanced charge transfer.