• Journal of the Korean Electrochemical Society
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• v.2 no.4
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• pp.202-208
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• 1999

Composite cathodes of $50/50\;vol\%$ LSM-YSZ $(La_{-x}Sr_xMnO_3-yttria\;stabilized\;zirconia)$ were deposited onto dense YSZ electrolytes by colloidal deposition technique. The cathode characteristics were then examined by scanning electron microscopy (SEM) and studied by ac-impedance spectroscopy (IS). The conditioning effects on LSM-YSZ cathodes were seen and remedies for these effects were noted in order to improve the performance of a solid oxide fuel cell (SOFC). The effects of temperature on impedance, surface contamination on cathode bonding to YSZ electrolyte, changing Pt paste, aerosol spray technique applied to curved surface on microstructure and cell to cell variability were solved by testing at $900^{\circ}C$, sanding the YSZ surface, using only one batch of Pt paste, using flat YSZ plates and using consistent procedures and techniques, respectively. And then, reproducible impedance spectra were confirmed by using the improved cell and the typical spectra measured for an (air)LSM-YSZ/YSZ/LSM-YSZ(air) cell at $900^{\circ}C$ were composed of two depressed arcs. Impedance characteristics of the LSM-YSZ cathodes were also affected by experimental conditions such as catalytic interlayer, composite cathode compositions and applied current.

• Journal of the Korean Magnetics Society
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• v.9 no.6
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• pp.306-311
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• 1999

$La_{2/3}Sr_{1/3}MnO_3(LSMO)/YSZ/SiO_2/Si(100)$ polycrystalline thin films were fabricated be chelated sol-gel method The effect of YSZ buffer layer at low field (120 Oe) spin-polarized tunneling magnetotransport (TMR) properties of LSMO thin film was studied at room temperature. Single perovskite LSMO thin films was obtained. The maximum TMR ratio was increased from 0.2 to 0.42 % by the insertion of YSZ buffer. YSZ as diffusion barrier was attributed to the fine microstructure of LSMO thin films and the reduction of dead layer between LSMO and $SiO_2/Si(100)$ interfaces.

• 한국전기화학회:학술대회논문집
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• 1998.10a
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• pp.92-92
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• 1998

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.05a
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• pp.128-128
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• 1999

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.158-159
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• 1998

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.1
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• pp.8-12
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• 1999

$\textrm{WO}_3$ semiconductive film, which is known to have a sensitivity on $\textrm{NO}_X$ gas was prepared on 8YSZ (8% Yttria stabilized $\textrm{ZrO}_2$) ionic conductor substrate that has oxygen ion pumping effect. Microstructure and electrical properity, especially $\textrm{NO}_X$ sensitivity as a function of DC voltage applied to 8YSZ substrate was examined. When the $\textrm{WO}_3$ film was annealed, it showed amorphous structure, while crystallization was occurred at $600^{\circ}$C revealing orthorhombic phase of $\textrm{WO}_3$. As the annealing temperature increases, (111) and (001) peaks of $\textrm{WO}_3$ film was enhanced. At $400^{\circ}C$ when DC voltage was applied, comparing with no DC bias, more stable and large response characteristics was showed, and the best sensitivity was observed at 2V. Recovery characteristics of NO gas was much better that that of $\textrm{NO}_2$ gas.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.487-492
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• 2011

The effect of the application of lanthanum strontrium manganite and yttria-stabilized zirconia (LSM-YSZ) nano-composite fabricated by pulsed laser deposition (PLD) as a cathode of solid oxide fuel cell (SOFC) is studied. A gradient-structure thin-film cathode composed of 1 micron-thick LSM-YSZ deposited at an ambient pressure ($P_{amb}$) of 200 mTorr; 2 micron-thick LSM-YSZ deposited at a $P_{amb}$ of 300 mTorr; and 2 micron-thick lanthanum strontium cobaltite (LSC) current collecting layer was fabricated on an anode-supported SOFC with an ~8 micron-thick YSZ electrolyte. In comparison with a 1 micron-thick nano-structure single-phase LSM cathode fabricated by PLD, it was obviously effective to increase triple phase boundaries (TPB) over the whole thickness of the cathode layer by employing the composite and increasing the physical thickness of the cathode. Both polarization and ohmic resistances of the cell were significantly reduced and the power output of the cell was improved by a factor of 1.6.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.189-192
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• 2014

Yttria-stablized zirconia (YSZ) is the most commonly used electrolyte material, but the reduction in working temperature leads to insufficient ionic conductivity. Ceria based electrolytes (GDC) are more attractive in terms of conductivity at low temperature, but these materials are well known to be reducible at very low oxygen partial pressure. The reduction of electrolyte resistivity is necessary to overcome cell performance losses. So, thin YSZ/GDC bilayer technology seems suitable for decreasing the electrolyte resistance at lower operating temperatures. Bilayer electrolytes composed of a galdolinium-doped $CeO_2$ ($Ce_{0.9}Gd_{0.1}O_{1.95}$, GDC) layer and yttria-stabilized $ZrO_2$ (YSZ) layer with various thicknesses were deposited by RF sputtering and E-beam evaporation. The bilayer electrolytes were deposited between porous Ni-GDC anode and LSM cathode for anode-supported single cells. Thin film structure and surface morphology were investigated by X-ray diffraction (XRD), using $CuK{\alpha}$-radiation in the range of 2ce morphol$^{\circ}C$. The XRD patterns exhibit a well-formed cubic fluorite structure, and sharp lines of XRD peaks can be observed, which indicate a single solid solution. The morphology and size of the prepared particles were investigated by field-emission scanning electron microscopy (FE-SEM). The performance of the cells was evaluated over $500{\sim}800^{\circ}C$, using humidified hydrogen as fuel, and air as oxidant.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1298-1300
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• 1997

금속기판상 초전도 $YBa_2CU_3O_{7-{\delta}}$ (YBCO) 박막을 yttria-stabilized zirconia (YSZ) 완충막을 이용하여 in situ 펄스 레이저 증착법에 의해 증착하였다. YBCO 박막을 직접 금속기판에 증착하게 되면 YBCO 박막과 금속기판 사이의 계면에서 상호확산현상이 발생하기 때문에 이를 방지하기 위해 YSZ 완충막이 사용되었다. YSZ 완충막의 증착온도가 박막의 결정성과 전기적 특성에 미치는 영향을 알아보기 위해 YSZ 완충막은 여러 가지 온도로 증착되었다. YBCO 박막의 증착온도와 같은 온도로 YSZ 완충막을 증착했을 때보다 YBCO 박막의 증착온도보다 높은 온도로 YSZ 완충막을 증착했을 경우, 증착된 YBCO 박막은 x선 회절에 의해 c 축 방향으로 성장하였음을 알 수 있었고, 저항이 0이 되는 임계온도가 83K가 되는 실험 결과를 얻었다.

• Journal of the Korean Ceramic Society
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• v.33 no.1
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• pp.25-34
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• 1996

Yttria stabilized zirconia (YSZ) thin films were prepared by the electrochemical vapor deposition (EVD) method on the porous Al2O3 substrates which were fabricated by different substrate thickness and porosity. Film growth rates decreased with increase on the substrate thickness and porosity and obeyed a parabolic rate law. Activa-tion energy calculated from the parabolic rate onstants was 69.9 kcal/mol. With increase on the deposition time, monoclinic phase was appeared and then disappeared. YSZ penetrated deeply into substrates when the EVD temperature decreased. Electrical conductivity of the films was 0.09 S/cm at 100$0^{\circ}C$ similar to the value of YSZ single crystal.