• 한국세라믹학회지
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• 제31권12호
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• pp.1529-1535
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• 1994

Electrical conduction mechanisms of RuO2-based thick film resistors were investigated with frequency depandence on AC conductivity. Electrical conduction mechanisms of lower resistivity system (100{{{{ OMEGA }}/sq) sintered at 600~90$0^{\circ}C$ were all metallic conduction mechanism. In case of higher resistivity (10K{{{{ OMEGA }}/sq) system, the electrical conduction mechanisms were very depenent on sintering temperature. When sintering temperature was $600^{\circ}C$, the electrical conduction mechamism was ionic, and as increasing the sintering temperature, the electrical conduction mechanism was changed from ionic to hopping conduction mechanism.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.282-285
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• 2009

This study presents preparation and characterization of composite membranes based on ionic liquids. The ionic liquids act as water in sulfonated membranes. On the behalf of ionic conduction through ionic liquid inside the membranes, non-aqueous membranes showed Arrenhius dependence on temperature with no external humidification. It was implied that hopping mechanism of proton was dominant in the ionic liquid based membranes. In addition, small angle X-ray (SAXS) studies provided the information on morphology of ionic clusters formed by the interaction between sulfonic acid groups of the polymers and ionic liquids. The SAXS spectra showed matrix peaks, ionomer peaks and Prodo's law for Nafion based composite membranes and only matrix peaks for hydrocarbon based ones. However, ionic conductivity and atomic force microscopy (AFM) images showed the clear formation of ionic clusters of the hydrocarbon based composite membranes. It implies for ionic liquid based high temperature membranes that it is important to use sulfonated polymers as solid matrix of ionic liquid which can form clear ionic clusters in SAXS spectra.

• 한국세라믹학회지
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• 제32권8호
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• pp.957-965
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• 1995

The ionic conductivityof NASICON solid electrolytes was simulated by using Monte Carlo Method (MCM) based on a hopping model as functions of temoperature and composition. Two conduction paths were used : jumping from Na1 to Na2 and jumping from Na1 to Na2 and jumping from Na2 to Na2. Vacancy availability factor, V was affected by composition, temperature and the conduction paths. For β"-Alumina, it was known that the minimum of charge correlation factor, fc appears at the composition, p=0.5, but there was not shown the minimum of fc for NASICON. When the NASICON composition, x, approaches 2.5, the curve of In σT vs. 1/T* was shown Arrhenius behavior and also In (VWfc) was a linear function of 1/T*. The results of simulations on the considered conduction paths didn't agree with the experimental results. Thus it will be necessary to include the another Na sites as mid-Na site on the conduction path to obtain the better results.

• 한국세라믹학회지
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• 제33권4호
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• pp.385-390
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• 1996

The electrical resistivity of the ceramic glaze coated on ceramic substrate plays an important role on the characteristics of the thick and thin film electrical circuits. In this study the effects of the various modifiers on the electrical resistivity were examined in SiO2-Al2O3-B2O3-RO-Na2O (RO=CaO , SrO, BaO, PbO) glass system. In alkali free glasses where divalent cations are responsible for electrical conduction the electrical conductivity of th glasses increased with the ionic size of divalent cations due to the decrease in the bond strength between oxyben and divalent cation. In Na2O containing glasses however where Na+ ion is responsible for electrical conduction the ionic conductivity decreased with the ionic size of divalent cations because the blocking effect of the cations on Na+ ion movement increased with larger divalent cations. Na+ ionic conduction also depended on the glass structure relaxation due to the corrdination number changes of B2O3 and Al2O3 which varied with the NaO2 content in the glass.

• 대한화학회지
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• 제53권1호
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• pp.42-50
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• 2009

유전율-분광법과 교류 전도도 측정 연구를 망간이 혼입된 층상구조의 $Na_{1.9}Li_{0.1}Ti_3O_7$에 시도하였다. 373-723K 온도와 100Hz-1MHz 주파수 영역에서 loss 탄젠트 (Tan$\delta$), 상대적 유전율 ($\varepsilon_{r}$) 그리고 교류 전도 도 ($\sigma_{ac}$)의 의존성을 혼입 유도체들에 대하여 조사하였다. 다양한 전도도 메커니즘이 존재하는데 MSLT-1과 MSLT-2의 경우에는 낮은 온도영역에서 전자에 의한 전도도를 보인다. MSLT-3의 경우에는 금지된 층간 이온 전 도도가 전자 전도도와 함께 존재한다. 이러한 층간 이온 전도도는 모든 혼입 유도체들에 대하여 중간 온도 영역에 존재한다. 가장 높은 온도 영역에서는 MSLT-1과 MSLT-2의 경우에는 이온 전도도와 polaron에 의한 전도도가 존재하고 MSLT-3에 대하여는 이온 전도도 만이 존재한다. 망간이 혼입된 층상구조의 $Na_{1.9}Li_{0.1}Ti_3O_7$에서 Loss 탄젠트 (Tan$\delta$)는 전자 전도도와 쌍극자의 위치, 그리고 공간 전하 분극화에 기인한다. 상대적 유전율의 증가는 층간 에 쌍극자 수의 증가에 기인하고 반면 상대적 유전율의 감소는 높은 혼입율에 따른 누전 전류의 증가에 기인한다.

• E2M - 전기 전자와 첨단 소재
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• 제11권11호
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• pp.9-17
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• 1998

The dependence of the ionic conductivity on the B-site ion substitution in (Li0.5La0.5)Ti1-xMxO3 (M=Sn, Zr, Mn, Ge) system has been studied. Same valence state and various electronic configuration and ionic radius of Sn4+, Zr4+, Mn4+ and Ge4+(4d10(0.69$\AA$), 4p6(0.72$\AA$), 3d10(0.54$\AA$) and 3d3(0.54$\AA$), respectively) induced the various crystallographic variaton with substitutions. So it was possibleto investigate the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic variations. We found that the conductivity increased with decreasing the radii of B-site ions or vice versa and octahedron distortion disturb the ion conduction. The reason for this reciprocal proportion of conductivity on the radius of B-site ions has been examined on the base of the interatomic bond strength change due to the cation substitutions. The results were good in agreement with the experimental results. Therefore it could be concluded that the interatomic bond strength change due to the cation substitutions may be the one of major factors influencing the lithium ion conductivity in perovskite(Li0.5La0.5) TiO3system.

• Journal of Electrochemical Science and Technology
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• 제12권1호
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• pp.1-20
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• 2021

In-depth knowledge of electrode processes is crucial for determining the electrochemical performance of lithium-ion batteries (LIBs). In particular, the conduction mechanisms of charged species in the electrodes, such as lithium ions (Li+) and electrons, are directly correlated with the performance of the battery because the overall reaction is dependent on the charge transport behavior in the electrodes. Therefore, it is necessary to understand the different electrochemical processes occurring in electrodes in order to elucidate the charge conduction phenomenon. Thus, it is essential to conduct fundamental studies on electrochemical processes to resolve the technical challenges and issues arising during the ionic and electronic conduction. Furthermore, it is also necessary to understand the transport of charged species as well as the predominant factors affecting their transport in electrodes. Based on such in-depth studies, potential approaches can be introduced to enhance the mobility of charged entities, thereby achieving superior battery performances. A clear understanding of the conduction mechanism inside electrodes can help overcome challenges associated with the rapid movement of charged species and provide a practical guideline for the development of advanced materials suitable for high-performance LIBs.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.230-236
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• 2021

Ionic conduction mechanism of Mg-Al layered double hydroxides (LDHs) intercalated with CO₃^2- (Mg-Al CO₃^2- LDH) was studied. The electromotive force for the water vapor concentration cell using Mg-Al CO₃^2- LDH as electrolyte showed water vapor partial pressure dependence and obeyed the Nernst equation, indicating that the hydroxide ion transport number of Mg-Al CO₃^2- LDH is almost unity. The ionic conductivity of Mg(OH)₂, MgCO₃ and Al₂(CO₃)₃ was also examined. Only Al₂(CO₃)₃ showed high hydroxide ion conductivity of the order of 10^-4 S cm^-1 under 80% relative humidity, suggesting that Al₂(CO₃)₃ is an ion conducting material and related to the generation of carrier by interaction with water. To discuss the ionic conduction mechanism, Mg-Al CO₃^2- LDH having deuterium water as interlayer water (Mg-Al CO₃^2- LDH(D₂O)) was prepared. After the adsorbed water molecules on the surface of Mg-Al CO₃^2- LDH(D₂O) were removed by drying, DC polarization test for dried Mg-Al CO₃^2- LDH(D₂O) was examined. The absorbance attributed to O-D-stretching band for Mg-Al CO₃^2- LDH(D₂O) powder at around the positively charged electrode is larger than that before polarization, indicating that the interlayer in Mg-Al CO₃^2- LDH is a hydroxide ion conduction channel.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.288-295
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• 1999

Partial conductivities contributed by electron holes, oxygen ions, and protons were caluclated in $SrZr_{0.95}Y_{0.05}O_{2.975}$, using the reported formulae derived from the defect chemistry of HTPCs. Required parameters were obtained from the graphical analysis of total conductivity variation against partial pressure of water vapor and oxygen. Predicted overall conductivities showed a reasonable agreement with experimental measurements. The conductivity of the material showed a linear increase with square root of the water vapor pressure. This increase was due to proton conduction in an almost pure ionic conductivity. The calculation of partial conductivities at $800^{\circ}C$ resulted in an almost pure ionic conductivity at $P_{02}=10^{-10}$ atm and a predominant hole conductivity at $P_{02}=10^{-10}$ atm. Pure proton conduction was not expected at this temperature, contrary to the earlier reports. Discussions were made in relation with reported thermodynamic data and defect structure of the material. It was shown that from the total conductivity dependence on water vapor pressure, the pure ionic conductivity at low oxygen partial pressures could be separated into protonic and oxygen ionic conductivity in $ZrO_2$-based HTPCs.

• 한국세라믹학회지
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• 제33권6호
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• pp.645-652
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• 1996

The ionic conductivity of NASICON (Na Super Ionic Conductor) solid electrolyte was simulated by using Monte Carlo Method (MCM)based on a hopping model. We assumed that the conduction path of Na ions is Na1→mid-Na→Na2 where the mid-Na sites are shallow potential sites to induce 'a breathing-like movement' of Na ions in the NASICON framework. The minimum of charge correlation factor Fc and the maximum of appeared at nearby x=2.0 The occupancy of mid-Na site affected the depth of potential barrier and the conduc-tivity of the NASICON. At above x=0.3 ln σT vs. 1/T* plots have been shown Arrhenius behavior but in (VWfc)vs. 1/T* have been shown the Arrhenius type tendency at x=1 MCM results accorded with the experi-mental procedure. The role of mid-Na on Na+ ion conduction could be explained by an additional driving force and a breating-like movement model for motions of Na+ ions in the NASICON framework. As we couldn't clearly remarked the model which is the better it seems reasonable to conclude that these hypothesies are suitable to explain the FIC behavior at NASICON.