• 한국세라믹학회지
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• 제41권12호
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• pp.900-906
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• 2004

현재까지 개발되어 온 고체산화물 연료전지는 전해질로 사용되는 산소이온전도성 산화물의 저온에서의 낮은 전도도로 인해 그 사용영역이 제한되어 왔으며, 기판재료가 연료가스 확산층으로 사용되어야 한다는 점 때문에 저온작동을 위한 박막화 역시 명확한 한계를 가지고 있다. 이러한 문제점은 고도의 평활도를 갖는 균일한 나노기공성 기판재를 도입함으로써 해결될 수 있으며, 본 연구에서는 나노기공성 기판에 비정질 금속박막을 증착/산화하는 방안을 제시한다. 초박막형 성공정으로서, 산화 후 산소이온전도성 산화물을 구성하는 합금 타겟을 장착한 DC-magnetron sputter를 사용하여 $20{\sim}200nm$의 기공크기를 갖는 나노기공성 양극산화 알루미나 기판에 비정질 금속합금막을 형성하여 산화/열처리 과정을 거쳐 초박막 산화물 전해질의 제조공정을 실현하였다. 얻어진 박막의 가스투과특성, 입자/입계의 관찰, 상전이에 따른 결정구조/미세구조변화를 관찰하여 초박막 증착 및 전해질의 나노구조제어에 필요한 제반 기본물성데이터를 확보하였다.

• 센서학회지
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• 제3권2호
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• pp.40-49
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• 1994

$CaF_{2}$ 불화물 고체전해질을 모물질로하는 저온동작용($300^{\circ}C{\sim}$500^{\circ}C) 산소센서를 제조하였다. $CaF_{2}$ 산소센서는 수축률과 SEM사진의 결과를 토대로 $850^{\circ}C$-3hr 동안 열처리 하였다. 디스크형 산소 센서는 기준전극으로 Air($O_{2}:21%$)|Pt를, 전해질로는 $CaF_{2}$, 감지전극으로 Pt를 사용하였으며, 기준전극 내장형 산소센서는 기준전극으로 NiO/Ni (30:70)을 사용하였다. 디스크형 산소센서의 경우 측정온도 $400^{\circ}C$에서 산소농도($0.1 %{\sim}10%$)로 변화시 45mV 정도의 기전력 변화를 보였으며, 기준전극 내장형의 경우는 40mV의 변화를 보였다.

• 센서학회지
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• 제7권5호
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• pp.319-326
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• 1998

연속 기체흐름계에서 감지막으로 $Na_2CO_3$와 $MCO_3$ ($M=Cs_2,K_2,Li_2,Ca$)를 입힌 $Na^+$ 이온 전해질 센서가 $CO_2$ 가스를 감지할 때 anode반응을 도출하였다. 흔히 사용되는 전기화학 센서에 대해 일반적으로 알려진 전체 전극반응인 $MCO_3=MO+CO_2$ 반응은 위의 $Na^+$이온 전해질 센서에는 적합한 반응이 아니었다. 따라서 anode 반응은 전체cell 내의 ionic balance를 유지하기 위해 전해질과 감지막 계면에 이온교환반응을 첨가시킴으로써 도출할 수 있었으며 anode반응은 $Na_2CO_3$ 및 감지막의 금속($M^{++}$) 이온이 포함된 산화물이 참가하는 반응임을 알 수 있었다. 이와 같이 도출된 전극반응으로부터 구한 EMF와 일시 기체흐름계에서의 출력 EMF와의 차이를 아울러 검토하였다. 이러한 출력에서의 차이는 $CO_2$와 $O_2$의 분압과 분위기가스와 전극물질과의 비가역반응에 기인됨을 알았다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.26-33
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• 1995

Silicone Rubber (SR)-based potassium- and sodium-selective solid-state electrodes have been developed for the portable blood electrolyte analyzer system. The electrochemical performance of these electrodes have been evaluated with a static experimental setup and with the newly developed blood electrolyte analyzer system (model; HS603). It has been shown that their potentiometric properties are essentially comparable to those of PVC-based ion-selective electrodes, but with greatly improved lifetime (200 and 40 days for potassium and sodium sensors, respectively) and potential stability (within $\pm0.1$ mV). Clinical tests have been performed with real serum samples and the results have been compared with those obtained from Ciba-Corning BGA 288 system; correlations were excellent, proving its practical utility as a new commercial system.

• 한국수소및신에너지학회논문집
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• 제7권1호
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• pp.29-37
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• 1996

Alkaline water electrolysis has been commercialized as the only large-scale method for a long time to produce hydrogen and the technology is superior to other methods such as photochemical, thermochemical water splitting, and thermal decomposition method in view of efficiency and related technical problem. However, such conventional electrolyzer do not have high electric efficiency and productivity to apply to large scale hydrogen production for energy or chemical feedstocks. Solid polymer electrolyte water electrolysis using a perfluorocation exchange membrane as an $H^+$ ion conductor is considered to be a promising method, because of capability for operating at high current densities and low cell voltages. So, this is a good technology for the storage of electricity generated by photovoltaic power plants, wind generators and other energy conversion systems. One of the most important R&D topics in electrolyser is how to minimize cell voltage and maximize current density in order to increase the productivity of the electrolyzer. A commercialized technology is the hot press method which the film type electrocatalyst is hot-pressed to soild polymer membrane in order to eliminate the contact resistance. Various technologies, electrocatalyst formed over Nafion membrane surface by means of nonelectrolytic plating process, porous sintered metal(titanium powder) or titanium mesh coated with electrocatalyst, have been studied for preparation of membrane-electrocatalyst composites. In this study some experiments have been conducted at a solid polymer electrolyte water electrolyzer, which consisted of single cell stack with an electrode area of $25cm^2$ in a unipolar arrangement using titanium mesh coated with electrocatalyst.

• 한국수소및신에너지학회논문집
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• 제16권2호
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• pp.103-110
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• 2005

Proton conducting solid polymer electrolyte (SPE) membranes have been used in many energy technological applications such as water electolysis, fuel cells, redox-flow battery, and other electrochemical devices. The availability of stable membranes with good electrochemical characteristics as proton conductivity at high temperatures above 80 $^{\circ}C$ and low cost are very important for its applications. However, the presently available perfluorinated ionomers are not applicable because of high manufacturing cost and high temperature use to the decrease in the proton conductivity and mechanical strength. In order to make up for the weak points, the block copolymer (BPSf) of polysulfone and poly (phenylene sulfide sulfone) were synthesized and sulfonated. The electrolyte membranes were prepared with phosphotungstic acid (HPA)/sulfonated BPSf via solution blending. This study would be desirable to investigate the interaction between the HPA and sulfonated polysulfone. The results showed that the characteristics of SPSf/HPA blend membrane was a better than Nafion at high temperature, 100 $^{\circ}C$. These membranes proved to have a high proton conductivity, $6.29{\times}10-2$ S/cm, a water content, 23.9%, and a ion exchange capacity, 1.97 meq./g dry membrane. Moreover, some of the membranes kept their high thermal and mechanical stability.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.306-308
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• 2007

Poly(ethylene glycol) dimethyl ether (PEGDME)/fumed silica/ 1-methyl -3-propylimidazolium iodide (MPII)/$I_2$ mixtures were used as polymer electrolytes in solid state dye-sensitized solar cells (DSSCs). The contents of MPII were changed and the concentration of $I_2$ was fixed at 0.1 mole% with respect to the MPII. The maximum ionic conductivity was obtained at [EG]:[MPII]:[$I_2$]=10:1.5:0.15. It was supposed that the maximum of ionic conductivities would match with that of cell efficiencies, if the ionic conductivity is a rate determining step in the sol id state DSSCs. However, the maximum composition did not show the maximum solar cell performance, indicating the mismatch between ionic conductivity and cell performance. This suggests that the ionic conductivity may not be the rate controlling step in determining the cell efficiency in these experimental conditions, whereas other parameters such as the electron recombination might play an important role. Thus, we tried to modify the surface of the $TiO_2$ particles by coating a thin metal oxide such as $Al_2O_3$ or $Nb_2O_5$ layer to prevent electron recombination. As a result, the maximum of the cell efficiency was shifted to that of the ionic conductivity. The peak shifts were also attempted to be explained by the diffusion coefficient and the lifetime of electrons in the $TiO_2$ layer.

• 한국세라믹학회지
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• 제51권3호
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• pp.208-217
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• 2014

$La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2-x}Zn_xO_{2.8}$(LSGMZ, X=0-0.05) was prepared using a solid state reaction method. Two secondary phases ($LaSrGaO_4$ and $LaSrGa_3O_7$) of powders were identified by X-ray diffraction analysis. The relative amount of these secondary phases depended on the calcination conditions (temperature and time) and Zn content. The sintering density of LSGMZ was enhanced by increasing the Zn content and calcination temperature at the low sintering temperatures ($1250-1300^{\circ}C$). The relationship between the sintering density of LSGMZ and the synthesis conditions was discussed considering the phase analysis results.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1200-1207
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• 2020

본 연구에서는 다공성 활성탄소와 금속유기골격체 복합재료 기반의 전극 재료와 "이온젤" 이라고 불리는 고분자 고체 전해질을 이용하여 슈퍼커패시터를 제작 하였으며, 금속유기골격체의 함량에 따른 전기화학적 거동을 관찰하여 보았다. 슈퍼커패시터의 전기화학적 특성은 순환전압전류법(CV), 전기화학적 임피던스 분광법(EIS) 및 전정류 충·방전법(GCD)으로 분석하였으며, 그 결과로, 다공성 활성탄소 대비 금속유기골격체를 0.5 wt% 첨가 하였을 때 가장 높은 전기용량값을 확인 할 수 있었으며, 0.5 wt% 이상의 금속유기골격체의 함유량은 전기화학적 특성 감소에 영향을 주는 것으로 사료되며, 이러한 결과를 바탕으로 제조된 다공성 활성탄소/금속유기골격체 복합재료 기반의 슈퍼커패시터는 다양한 분야에 활용이 가능할 것으로 판단된다.

• 한국재료학회지
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• 제13권2호
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• pp.115-119
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• 2003

The thick film type sensor having Pt/Na Super Ionic Conductor(NASICON) solid electrolyte/Pt/$Na_2$$SO_4$/Pt catalyst system for $SO_2$gas was fabricated by screen-print method. The phase of Na Super Ionic Conductor solid electrolyte sintered at different temperature of 1050, 1150,$ 1250^{\circ}C$ and for different time of 1.5, 2.5, 3.5 hr were investigated by XRD. The Electromotive Force variation of the sensor with $SO_2$concentrations and operating temperatures were investigated. The major phase of Na Super Ionic Conductor film sintered at 115$0^{\circ}C$ for 3.5 hr was sodium zirconium silicon phosphate($Na_3$Zr$_2$$Si_2$PO$_{12}$). The Nernst's slope of Na Super Ionic Conductor sensor for $SO_2$gas with the variation of concentration from 10 to 100 ppm was 167.14 ㎷/decade at the operating temperature of $500 ^{\circ}C$. The increase of oxygen partial pressure was not affected to the variation of Nernst's slope.e.