• Title/Summary/Keyword: Polymer electrolyte membrane

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Improving Power Conversion Efficiency and Long-term Stability Using a Multifunctional Network Polymer Membrane Electrolyte; A Novel Quasi-solid State Dye-sensitized Solar Cell

  • Gang, Gyeong-Ho;Gwon, Yeong-Su;Song, In-Yeong;Park, Seong-Hae;Park, Tae-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.484.2-484.2
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    • 2014
  • There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

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A Study on the Ion Permeability Characteristics in Nano-Polymer Membrane Structures (나노고분자막 구조의 이온투과 특성에 관한 연구)

  • Kim, Yoo-Young
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.1
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    • pp.133-137
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    • 2006
  • Ion permeability characteristics in nano-polymer membrane structures are performed to investigate the chemical composition and characteristics of MEA(Membrane Electrolyte Assembly) which is one of the most important parts to decide the performance in PEMFC(Polymer Electrolyte Membrane Fuel Cell) system. Subsequently, the MEA manufacturing process is presented for the uniformed MEA product. In the meantime, the analysis of SEM(Scanning Electron Microscope) is carried out in order to investigate the joint aspect and chemical composition of MEA. As a result of SEM analysis, it is found that the bonded catalyst and carbon composition contain the reasonable amount to get unit cell output. It is also found that the humidification gives the better performance result slightly.

Characteristics of Fabricated MEA(Membrane Electrode Assembly) on Polymer Electrolyte Membrane Fuel Cell Made by the Screen Printing Method (스크린 프린팅법을 이용하여 제조된 고분자 전해질 연료전지에서 MEA(조합 막 전극)의 특성)

  • 임재욱;최대규;류호진
    • Journal of the Semiconductor & Display Technology
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    • v.2 no.4
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    • pp.27-30
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    • 2003
  • The effect of fabrication method of catalytic layer on electrode performance has been investigated. Brush, spray gun and screen printer were used as fabrication tool and catalytic layers were formed by several methods in screen printing. Direct screen printing on polymer membrane, screen printing on carbon paper, and their combined method were applied. In the electrode fabricated by the screen printing method, Pt loading of Pt/C catalysts could be cut down to 50%, compared with results by the brushing and spraying methods. The best result of electrode was obtained as 0.6 V, at 1 A/$\textrm{cm}^2$ when catalytic layer was formed by the combined way.

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Electrochemical Characteristics of Ion-Exchange Membrane and Charged Mosaic Membrane (복합 하전 모자이크 막과 이온교환 막의 전기적화학적 특성)

  • Yang, Wong-Kang;Song, Myung-Kwan;Cho, Young-Suk
    • Membrane Journal
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    • v.17 no.1
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    • pp.37-43
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    • 2007
  • The effect of anionic and cationic exchange polymer layer on the chronopotentiometry (CP) and current voltage curves (I-V) of charged composite membrane are investigated. Also, the ion transport near the interface between electrolyte and ionic exchange polymer membranes (anionic and cationic ones) and charged mosaic polymer composite membrane is studied. The results show that both anionic and cationic polymer exchange membranes exhibit lower voltage drop over range of applied current density and possess favorable industrial application potentials, especially at low KCl concentration. While the charged mosaic polymer composite membrane didn't show any current-voltage change, irrespective to the type and the concentration of used electrolyte. CP and I-V measurements are effectively used to give some fundamental understanding for ion transport behavior of ion exchange polymer membrane near the interlace.

Photovoltaic Performance of Dye-sensitized Solar Cells assembled with Hybrid Composite Membrane based on Polypropylene Non-woven Matrix

  • Choi, Yeon-Jeong;Kim, Dong-Won
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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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.

Silver Polymer Electrolyte Membranes for Facilitated Olefin Transport: Carrier Properties, Transport Mechanism and Separation Performance

  • Kim, Jong-Hak;Kang, Yong-Soo
    • Macromolecular Research
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    • v.12 no.2
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    • pp.145-155
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    • 2004
  • Facilitated transport membranes for the separation of olefin/paraffin mixtures have long been of interest in separation membrane science because olefins, such as propylene and ethylene, which are important chemicals in petrochemical industries, are currently separated by energy-intensive cryogenic distillation processes. Recently, solid polymer electrolyte membranes containing silver ions have demonstrated remarkable performance in the separation of olefin/paraffin mixtures in the solid state and, thus, they can be considered as alternatives to cryogenic distillation. Here, we review recent progress, and critical issues affecting in the use of facilitated olefin transport membranes; in particular, we provide a general overview with reference to carrier properties, transport mechanisms, and separation performance.

Influence of the Catalyst Composition on Electrode Performance for Polymer Electrolyte Membrane Fuel Cells (촉매조성이 PEM용 연료전지의 전극특성에 미치는 영향)

  • 임재욱;최대규;류호진
    • Journal of the Microelectronics and Packaging Society
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    • v.9 no.3
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    • pp.43-48
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    • 2002
  • In this study, high performance electrode catalyst was developed in fabrication of membrane electrode assembly for PEMFCs(Polymer Electrolyte Membrane Fuel Cells). The I-V characteristics were measured to evaluate the influence of Nafion solution and Pt loading amount in the catalyst composition. The electrode characteristics were also investigated with respect to temperature change. The electrode performance was optimized at Nafion 5 wt% and 0.5 mg Pt/$\textrm{cm}^2$ content. The increase in the concentration of Nafion solution resulted in the decrease in electrode performance. At $80^{\circ}C$ of unit cell, I-V characteristics excelled those obtained at lower temperature. There was no difference in performance at low current density, but the improvement of voltage value in higher temperature could be found at high current density.

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Effect of Electrolyte on Preperation of Porous Alumina Membrane by Anodic Oxidation (양극산화에 의한 다공성 알루미나 막의 제조시 전해질의 영향)

  • Lee, Chang-Woo;Hahm, Yeong-Min;Kang, Hyun-Seop;Chang, Yoon-Ho
    • Applied Chemistry for Engineering
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    • v.9 no.7
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    • pp.1047-1052
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    • 1998
  • The porous alumina membrane was prepared from aluminum metal(99.8%) by anodic oxidation using DC power supply of constant current mode in aqueous solution of sulfuric, oxalic, phosphoric and chromic acid. Pore size and distribution, membrane thickness, morphology and crystal structure were examined with several anodizing conditions : reaction temperature, electrolyte concentration, current density and electrolyte type. It was found that ultrafiltration membrane was fabricated in electrolyte of sulfuric, and oxalic acid. On the other hand, microfiltration membrane was fabricated in electrolyte of phosphoric, and chromic acid. Also, it was shown that crystal structure of porous alumina membrane prepared in sulfuric, oxalic, and phosphoric acid was amorphous, whereas porous alumina membrane prepared in chromic acid had ${\gamma}$ type of crystal structure.

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Polymer Materials for Polymer Electrolyte Fuel Cells: Sulfonated Poly(ether sulfone)s for Fuel Cell Membranes

  • Kim, H.J.;Lee, S.Y.;Cho, E.;Ha, H.Y.;Oh, I.H.;Lim, T.H.
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.185-185
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    • 2006
  • The performances of proton exchange membrane fuel cell (PEMFC), direct formic acid fuel cell (DFAFC) and direct methanol fuel cell (DMFC) with sulfonated poly(ether sulfone) membrane are reported. Pt/C was coated on the membrane directly to fabricate a MEA for PEMFC operation. A single cell test was carried out using $H_2/air$ gases as fuel and oxidant. A current density of $730\;mA/cm^2$ at 0.60 V was obtained at $70^{\circ}C$. Pt-Ru (anode) and Pt (cathode) were coated on the membrane for DMFC operations. It produced $83\;mW/cm^2$ of maximum power density. The sulfonated poly(ether sulfone) membrane was also used for DFAFC operation under several different conditions. It showed good cell performances for several different kinds of polymer electrolyte fuel cell applications.

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