• 한국막학회:학술대회논문집
• /
• 한국막학회 2008년도 춘계 총회 및 학술발표회
• /
• pp.154-157
• /
• 2008

• 한국세라믹학회지
• /
• 제42권6호
• /
• pp.425-431
• /
• 2005

Line Shaped Solid Oxide Fuel Cell (SOFC) with multilayered structure has been fabricated via direct-writing process. The cell is electrolyte of Ni-YSZ cermet anode, YSZ electrolyte and LSM cathode. They were processed into pastes for the direct writing process. Syringe filled with each electrode and electrolyte paste was loaded into the computer-controlled robe-dispensing machine and the paste was dispensed through cylindrical nozzle of 0.21 mm in diameter under the air pressure of 0.1 tow onto a moving plate with 1.22 mm/s. First of all, the anode paste was dispensed on the PSZ porous substrate, and then the electrolyte paste was dispensed. The anode/electrolyte and the PSZ substrate were co-fired at $1350^{\circ}C$ in air atmosphere for 3 h. The cathode layer was similarly dispensed and sintered at $1200^{\circ}C$ for 1 h. All the electrode/electrolyte lines were visually aligned during the direct writing process. The effective reaction area of fabricated SOFC was $0.03 cm^2$, and the thickness of anode, electrolyte and cathode was 20 $\mu$m, 15 $\mu$m, and 10 $\mu$m, respectively. The single line-shaped SOFC fabricated by direct-writing process exhibited OCV of 0.95 V and maximum power density of $0.35W/cm^2$ at $810^{\circ}C$.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2003년도 The 4th Korea-Italy Workshop
• /
• pp.129-132
• /
• 2003

Silica/SUS composite membranes were prepared for CO removal from products of methanol steam reforming. A support was prepared by coating Ni powder of sub-micron and SiO$_2$ sols of particle size of 500nm and 150nm in turns on a porous stainless steel (SUS) substrate. Silica top layer was coated on the modified support using colloidal sol with nanoparticle. As a result of mixture gas permeation test of silica composite membrane using H$_2$(99%)/CO(1%), CO concentration of 10000 ppm was reduced to under 81 ppm, which is acceptable in PEMFC anode gas specification. Permeation mechanism through the membrane was mainly molecular sieving.

• 한국세라믹학회지
• /
• 제43권2호
• /
• pp.85-91
• /
• 2006

Electron Beam Physical Vapor Deposition (EB-PVD) was applied to fabricate a thin film YSZ electrolyte with large area on the porous NiO-YSZ anode substrate. Microstructural and thermal stability of the as-deposited electrolyte film was investigated via SEM and XRD analysis. In order to obtain an optimized YSZ film with high stability, both temperature and surface roughness of substrate were varied. A structurally homogeneous YSZ film with large area of $12\times12\;cm^2$ and high thermal stability up to $900^{\circ}C$ was fabricated at the substrate temperature of $T_s/T_m$ higher than 0.4. The smoother surface was proved to give the better film quality. Precise control of heating and cooling rate of the anode substrate was necessary to obtain a very dense YSZ electrolyte with high thermal stability, which affords to survive after post heat treatment for fabrication a cathode layer on it as well as after long time operation of solid oxide fuel cell at high temperature.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 춘계학술발표대회
• /
• pp.31.1-31.1
• /
• 2009

Carbon nanotubes (CNTs) are attractive material because of their superior electrical, mechanical, and chemical properties. Furthermore, their geometric features such as a large aspect ratio and a small radius of curvature at tip make them ideal for low-voltage field emission devices including backlight units of liquid crystal display, lighting lamps, X-ray source, microwave amplifiers, electron microscopes, etc. In field emission devices for display applications, the phosphor anode is positioned against the CNT emitters. In most case, light generated from the phosphor by electron bombardment passes through the anode front plate to reach observers. However, light is produced in a narrow depth of the surface of the phosphor layer because phosphor particles are big as much as several micrometers, which means that it is necessary to transmit through the phosphor layer. Hence, a drop of light intensity is unavoidable during this process. In this study, we fabricated a transparent cathode back plate by depositing an ultra-thin film of single walled CNTs (SWCNTs) on an indium tin oxide (ITO)-coated glass substrate. Two types of phosphor anode plates were employed to our transparent cathode back plate: One is an ITO glass substrate with a phosphor layer and the other is a Cr-coated glass substrate with phosphor layer. For the former case, light was radiated from both the front and the back sides, where luminance on the back was ~30% higher than that on the front in our experiments. For the other case, however, light was emitted only from the cathode back side as the Cr layer on the anode glass rolled as a reflecting mirror, improving the light luminance as much as ~60% compared with that on the front of one. This study seems to be discussed about the morphologies and field emission characteristics of CNT emitters according to the experimental parameters in fabricating the lamps emitting light on the both sides or only on the cathode back side. The experimental procedures are as follows. First, a CNT aqueous solution was prepared by ultrasonically dispersing purified SWCNTs in deionized water with sodium dodecyl sulfate (SDS). A milliliter or even several tens of micro-liters of CNT solution was deposited onto a porous alumina membrane through vacuum filtration. Thereafter, the alumina membrane was solvated with the 3 M NaOH solution and the floating CNT film was easily transferred to an ITO glass substrate. It is required for CNT film to make standing CNTs up to serve as electron emitter through an adhesive roller activation.

• 센서학회지
• /
• 제17권1호
• /
• pp.9-14
• /
• 2008

In this paper, the gas responses of tungsten oxide films prepared by anodic reaction was discussed. Sensing electrodes and heating electrodes were patterned by photolithography method on quartz substrate. Porous tungsten oxide was fabricated in electrolyte solutions of 5 % HF (HF :$C_2H_6OH:H_2O$=3 : 2 : 20) by anodic reaction. The anodic reaction with metal (platinum wire) as a cathode and the sensing device as an anode was conducted under the various reaction times (1-10 min) at 10 mA/$cm^2$ The surface structure and morphology of the fabricated sensor have been analysed by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). All the peaks of XRD results were well indexed to the pure phase pattern. The average diameter of the porous tungsten oxide surface were ranged about 100 nm. The fabricaed sensor showed good sensitivity to 200 ppm toluene at operating temperature of $250^{\circ}C$.

• 한국수소및신에너지학회논문집
• /
• 제24권3호
• /
• pp.230-236
• /
• 2013

In this study, successive coating and co-sintering techniques have been used to fabricate LSM/GDC based cathode supported direct carbon fuel cells. The porous LSM/GDC cathode substrate, dense, thin and crack free GDC and ScSZ layers as bi-layer electrolyte, and a porous Ni/ScSZ anode layer was obtained by co-firing at $1400^{\circ}C$. The porous structure of LSM/GDC cathode substrate, after sintering at $1400^{\circ}C$, was obtained due to the presence of GDC phase, which inhibits sintering of LSM because of its higher sintering temperature. The electrochemical characterization of assembled cell was carried out with air as an oxidant and carbon particles in molten carbonate as fuel. The measured open circuit voltages (OCVs) were obtained to be more than 0.99 V, independent of testing temperature. The peak power densities were 116, 195 and $225mWcm^{-2}$ at 750, 800 and $850^{\circ}C$, respectively.

• 대한기계학회논문집B
• /
• 제36권9호
• /
• pp.931-935
• /
• 2012

본 연구에서는 저온형 연료전지와 고온형 연료전지의 작동 및 구성 요소 측면 단점들을 보완하기 위해 중온 영역에서 작동하는 박막 연료전지를 제작하였다. 박막 연료전지는 이트륨이 도핑된 바륨 지르코네이트(BYZ) 전해질과 백금 수소극/공기극으로 이루어져 있으며, 성능은 $350^{\circ}C$에서 측정하였다. 350nm의 두께를 가지는 백금 수소극은 다공성 기판 위에 스퍼터링 기법을 이용하여 증착하였다. BYZ전해질은 펄스레이저 기법을 이용하여 $1{\mu}m$ 증착하였고, 상부에 스퍼터링 기법을 이용하여 200nm의 두께를 가지는 백금 공기극을 증착하였다. 개회로 전압은 약 0.81V이었고, 최대 출력 성능은 11.9mW/$cm^2$이었다.

• 한국세라믹학회지
• /
• 제36권8호
• /
• pp.791-798
• /
• 1999

다공성 NiO-YSZ 기판위에 전착법(EPD; Electrophoretic Deposition)법과 담금(Dip-coating)법에 의해 음극지지형 고체연료전지용 이트리아 안정화 지르코니아 박막 제조법을 연구하였다. 이를 위해 슬러리 농도 및 시간에 따른 박막의 무게, 박막의 결함 및 미세구조변화에 영향을 주는 제조조건들을 살펴 봄으로써 전착법과 담금법의 차이를 보았다. 담금법에서는 막생성 초기인 30초까지 막의 무게가 증가하지만 그 후에는 탈락이 일어나 시간을 증가하여도 막의 무게가 오히려 감소하였다. 전착법에서는 임계 인가전류 이상에서 시간에 따라 막의 무게가 증가하고 균일하고 치밀한 막이 형성하였다 전장이 매우 낮은 0.035 mA/$cm^2$ 의 정전류를 120초 이상 장시간 인가하면 막의 흘러내림(sagging)으로 인한 결함이 발생하였다. 전착법에 의해 균일하고도 치밀하게 가스 누출성이 없는 음극지지형 고체산화물 연료전지에 적합한 전해질 박막을 제조할 수 있었다.

• 한국수소및신에너지학회논문집
• /
• 제33권1호
• /
• pp.38-46
• /
• 2022

Two different gas diffusion layers having noticeable differences in micro-porous layer's (MPL's) crack were studied as a substrate for the gas diffusion electrode (GDE) with different binder/carbon (B/C) ratios in high-temperature polymer electrolyte fuel cell (Ht-PEMFC). As a result, the performance defined as the voltage at 0.2 A/cm² and maximum power density from the single cells using GDEs from H23 C2 and SGL38 BC with different B/C ratios were compared. GDEs from H23 C2 showed a proportional increase of the voltage with the binder content on the other hand GDEs from SGL38 BC displayed a proportional decline of the voltage to the binder content. It was revealed that MPL crack influences the structure of catalyst layer in GDEs as well as affects the RC_athode which is in close connection with the Ht-PEMFC performance.