• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.439-442
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• 2007

A solid state Hg(Au)/HgO reference electrode was prepared utilizing gold amalgam solid particles. Solid fine powder of the gold amalgam was prepared by chemical reduction of Au(III) with NaBH4 followed by reduction of Hg(II) in the presence of gold fine particles. The solid content in the suspension of the gold amalgam particles and fine mercury oxide particles in DMF containing PVC was precipitated by the addition of a large amount of water to give solid Hg(Au)/HgO/PVC mixture. After drying, the mixture was pressure-molded to a physically stable Hg(Au)/HgO composite reference electrode material. The electrochemical characteristics of the electrode as a reference electrode were very similar to an ordinary Hg/HgO reference electrode. The electrode material can be molded and fabricated in any desired shape and size. The surface can be renewed by a simple polishing process whenever contaminated or deactivated. The applicability of the electrode in the electrochemical detection of carbohydrates after anion exchange separation was evaluated.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3128-3132
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• 2010

A disposable solid-state pH sensor was realized by utilizing two nanoporous Pt (npPt) electrodes and a copolyelectrolytic junction. One nanoporous Pt electrode was to measure the pH as an indicating electrode (pH-IE) and the other assembled with copolyelectrolytic junction was to maintain constant open circuit potential ($E_{oc}$) as a solid-state reference electrode (SSRE). The copolyelectrolytic junction was composed of cationic and anionic polymers immobilized by photo-polymerization of N,N'-methylenebisacrylamide, making buffered electrolytic environment on the SSRE. It was expected to make. The nanoporous Pt surrounded by a constant pH excellently worked as a solid state reference electrode so as to stabilize the system within 30 s and retain the electrochemical environment regardless of unknown sample solutions. Combination between the SSRE and the pH-IE commonly based on nanoporous Pt yielded a complete solid-state pH sensor that requires no internal filling solution. The solid state pH sensing chip is simple and easy to fabricate so that it could be practically used for disposable purposes. Moreover, the solid-state pH sensor successfully functions in calibration-free mode in a variety of buffers and surfactant samples.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.295-298
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• 1996

In this study, we have fabricated all solid state electrochromic devices using WO$_3$ film as the working electrode, V$_2$O$\_$5/ film as the counter electrode and PEO-LiClO$_4$-PC film as the solid electrolyte. The WO$_3$ thin films for working electrode and V$_2$O$\_$5/ thin films for counter electrode were deposited onto ITO glass by vacuum evaporation and were shown good electrochromic and state properties after 1x10$\^$5/ cycles. PEO-LiClO$_4$-PC polymer electrolyte can easily be formed into thin films, do not absorb in the visible region of the light. Therefore, such electrolyte have electrochromic properties suitable for large-scale all solid-state electrochromic devices. All solid-staeelectrochromic devices fabricated in this polymer electrolyte have optical modulation of 20%∼30% at 1.5 V.

• 세라미스트
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• 제22권2호
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• pp.170-181
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• 2019

All-solid-state batteries have received increasing attention because of their high safety aspect and high energy and power densities. However, the inferior solid-solid interfaces between solid electrolyte and active materials in electrode, which cause high interfacial resistance, reduce ion and electron transfer rate and limit battery performance. Recently, spark plasma sintering is emerging as a promising technique for fabricating solid electrolytes and composite-electrodes. Herein, this paper focuses on the overview of spark plasma sintering to fabricate solid electrolytes and composite-electrodes for all-solid-state batteries. In the end, future opportunities and challenges associated with SPS technique for all-solid-state batteries are described.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.57-58
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• 2022

Reinforced concrete (RC) structures play a significant role in the construction industries. An embeddable solid-state reference electrode (ESSRE) was used to evaluate the corrosion status of steel rebar in the concrete of various cover thicknesses that exposed to the maritime environment (3.5 % NaCl) in this study. From the open circuit potential measurement (OCP), the passive state, the corrosion uncertainty, and the 90% probability of corrosion state of the steel rebars in the concrete were monitored by ESSRE. From the electrochemical impedance spectroscopy (EIS) method, severe corrosion was observed at the exposure period of 1510, 1847, 2350, and 3020 h for C10, C15, C20, and C30 concrete, respectively. The results confirm that the ESSRE can be useful to identify the corrosion occurrence and severe corrosion of steel rebar embedded in different cover depth concrete structures.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.147-148
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• 2018

In order to compare the electrochemical performance with that of Calomel Electrode, MnO2 solid-state-electrode was fabricated and its potential and impedance were measured in chloride aqueous solution. As a result, the SCPS without chloride ions showed a potential of -200 mV or more and an impedance over 2000 Ωcm, but the potential below -600 mV and the impedance below -200 Ωcm showed as the chloride concentration in the solution increased. It is considered electrochemical studies on the corrosion of rebar are necessary for the MOE, which shows the same tendency as SCE and exhibits electrochemical performance, over the Mortar level in the future.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3253-3256
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• 2013

Lithium is a highly attractive material for high-energy-concentration batteries, since it has low weight and high potential. Rechargeable lithium-ion batteries (LIBs), which have the extremely high gravimetric and volumetric energy densities, are currently the most preferable power sources for future electric vehicles and various portable electronic devices. In order to improve the efficiency and lifetime, new electrode compounds for lithium intercalation or insertion have been investigated for rechargeable batteries. Solid-state nuclear magnetic resonance (NMR) is a very useful tool to investigate the structural changes in electrode materials in actual working lithium-ion batteries. To detect the in-situ microstructural changes of electrode and electrolyte materials, $^7Li-^{19}F$ double-resonance solid-state NMR probe with a static solenoidal coil for a 600-MHz narrow-bore magnet was designed, constructed, and tested successfully.

• ETRI Journal
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• 제42권1호
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• pp.129-137
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• 2020

All-solid-state batteries are promising energy storage devices in which high-energy-density and superior safety can be obtained by efficient cell design and the use of nonflammable solid electrolytes, respectively. This paper presents a systematic study of experimental factors that affect the electrochemical performance of all-solid-state batteries. The morphological changes in composite electrodes fabricated using different mixing speeds are carefully observed, and the corresponding electrochemical performances are evaluated in symmetric cell and half-cell configurations. We also investigate the effect of the composite electrode thickness at different charge/discharge rates for the realization of all-solid-state batteries with high-energy-density. The results of this investigation confirm a consistent relationship between the cell capacity and the ionic resistance within the composite electrodes. Finally, a concentration-gradient composite electrode design is presented for enhanced power density in thick composite electrodes; it provides a promising route to improving the cell performance simply by composite electrode design.

• 전기화학회지
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• 제22권4호
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• pp.139-147
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• 2019

고에너지밀도 대용량 리튬이온전지를 채용한 전기자동차 및 에너지저장시스템에서 발생하고 있는 발화사고로 인해, 고안전성 전고체 리튬이차전지(All-solid-state Lithium Secondary Battery, ALSB)에 대한 연구가 국내외에서 활발히 진행되고 있다. 하지만, 단순히 액체전해질을 고체전해질로만 바꾸는 것이 아니라, 이로 인해 수반되는 전극 및 전지 설계와 해석이 크게 달라진다는 점에서 해결해야 될 이슈들이 산재해 있다. 특히, 전지는 전극 설계에 따라 그 성능이 굉장히 상이함에도 불구하고, 실질적인 전고체 전지 실험 구현의 어려움으로 전고체 전극(All-solid-state Electrode, ASSE) 설계에 따른 성능 차이를 체계적으로 비교 분석하여 최적화하는 연구는 매우 제한적이다. 이를 극복하기 위한 방안으로, 가상의 3차원 전고체 전극 구조체를 형성하고, 형성된 구조체를 바탕으로 다양한 성능 결정 파라미터를 도출하며, 더불어 분석 전극을 포함한 전지의 성능까지 예측할 수 있는 기술을 개발하는 연구가 주목을 받기 시작했다. 본 총설에서는 3차원 전고체 전극 구조체 형성부터 전고체 리튬이차전지의 성능을 예측하는 기술까지 각각의 기술들이 갖고 있는 장단점을 폭넓게 다룰 것이며, 나아가 본 기술이 나아갈 최종적인 목표까지 간략히 기술하고자 한다.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.413-418
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• 2018

All-solid-state lithium batteries (ASSBs) using inorganic sulfide-based solid electrolytes are considered prospective alternatives to existing liquid electrolyte-based batteries owing to benefits such as non-flammability. However, it is difficult to form a favorable solid-solid interface among electrode constituents because all the constituents are solid particles. It is important to form an effective electron conduction network in composite cathode while increasing utilization of active materials and not blocking the lithium ion path, resulting in excellent cell performance. In this study, a mixture of fibrous VGCF and spherical nano-sized Super P was used to improve rate performance by fabricating valid conduction paths in composite cathodes. Then, composite cathodes of ASSBs containing 70% and 80% active materials ($LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$) were prepared by a solution-based process to achieve uniform dispersion of the electrode components in the slurry. We investigated the influence of binary carbon additives in the cathode of all-solid-state batteries to improve rate performance by constructing an effective electron conduction network.