• Title/Summary/Keyword: 전기전도성 폴리머

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Effect of Carboxylic Acid Group of Functionalized Carbon Nanotubes on Properties of Electrospun Polyacrylonitrile (PAN) Fibers (기능화된 탄소나노튜브의 카르복실산이 전기방사된 폴리아크릴로니트릴 섬유의 물성에 미치는 영향)

  • Park, Ok-Kyung;Kim, Ju-Hyung;Lee, Sung-Ho;Lee, Joong-Hee;Chung, Yong-Sik;Kim, Jun-Kyung;Ku, Bon-Cheol
    • Polymer(Korea)
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    • v.35 no.5
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    • pp.472-477
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    • 2011
  • To study the effects of the acid group of functionalized MWNT (multiwalled carbon nanotube) on the thermal and mechanical properties of polyacrylonitrile(PAN) nanofibers, acid ($H_2SO_4/HNO_3$) treated MWNT (O-MWNT) were further functionalized by diazonium salt reaction with 5-aminoisophthalic acid (IPA). Compared to O-MWNT, IPA-MWNT with isophthalic acid group showed a better dispersion stability in polar solvents and IPA-MWNT/PAN composite film displayed lower heat of reaction (${\Delta}H$) than that of homo PAN when stabilized under air atmosphere. The continuous electrospun fibers were prepared using a conductive water bath. PAN fibers containing 1 wt% of IPA-MWNT showed an increase of tensile strength by 100% and tensile modulus by 240% compared to the PAN fibers without IPA-MWNT.

Cathode materials advance in solid oxide fuel cells (고체산화물연료전지 공기극의 재료개발동향)

  • Son, Young-Mok;Cho, Mann;Nah, Do-Baek;Kil, Sang-Cheol;Kim, Sang-Woo
    • Journal of Energy Engineering
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    • v.19 no.2
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    • pp.73-80
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    • 2010
  • A solid oxide fuel cells(SOFC) is a clean energy technology which directly converts chemical energy to electric energy. When the SOFC is used in cogeneration then the efficiency can reach higher than 80%. Also, it has flexibility in using various fuels like natural gases and bio gases, so it has an advantage over polymer electrolyte membrane fuel cells in terms of fuel selection. A typical cathode material of the SOFC in conjunction with yttria stabilized zirconia(YSZ) electrolyte is still Sr-doped $LaMnO_3$(LSM). Recently, application of mixed electronic and ionic conducting perovskites such as Sr-doped $LaCoO_3$(LSCo), $LaFeO_3$(LSF), and $LaFe_{0.8}Co_{0.2}O_3$(LSCF) has drawn much attention because these materials exhibit lower electrode impedance than LSM. However, chemical reaction occurs at the manufacturing temperature of the cathode when these materials directly contact with YSZ. In addition, thermal expansion coefficient(TEC) mismatch with YSZ is also a significant issue. It is important, therefore, to develop cathode materials with good chemical stability and matched TEC with the SOFC electrolyte, as well as with high electrochemical activity.

Preparation and Characterization of PVA/PSSA-MA Electrolyte Membranes Containing Silica Compounds and Surface Fluorination for Fuel Cell Applications (연료전지 응용을 위한 실리카 성분을 함유하며 표면불소화된 PVA/PSSA-MA 막의 제조 및 특성 연구)

  • Kim, Dae-Hoon;Lee, Bo-Sung;Rhim, Ji-Won
    • Polymer(Korea)
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    • v.34 no.6
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    • pp.540-546
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    • 2010
  • In this manuscript, in order to reduce methanol permeability and, at the same time, to increase proton conductivity THS-PSA containing silica compound, responsible for methanol permeability reduction, and sulfonic acid, responsible for proton conductivity enhancement, was applied onto PVA/PSSA-MA membranes. And in order to improve durability, the resulting membranes, PVA/PSSAMA/THS-PSA, were exposed to 500ppm F2 gas at varying reaction times. The surface-fluorinated membranes were characterized through the measurement of contact angles, thermo-gravimetric analysis, and X-ray photoelectron spectroscopy to observe the physico-chemical changes. For the evaluation of the electro-chemical changes in the resulting membranes, its water contents, ion exchange capacity, proton conductivity, and methanol permeability were measured and then compared with the commercial membrane, Nafion 115. Finally, the membran electrode assembly(MEA) was prepared and the cell voltage against the current density was measured. As fluorination time increased, the contents of F2 increased up to maximum 4.3% and to depth of 50 nm. At 60 min of fluorination, the proton conductivity was 0.036 S/cm, larger than Nafion 115 at 0.024 S/cm, and the methanol permeability was $9.26E-08cm^2/s$, less than Nafion 115 at $1.17E-06cm^2/s$.