• Title/Summary/Keyword: Electrode microstructure

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Development of prepareation technology of materials for high temperature electrolysis (고온수전해용 전극물질 개발)

  • Seo, Min-Hye;Hong, Hyun-Seon;Kang, Kyoung-Hoon;Kim, Jong-Min;Lee, Sung-Koo;Yun, Yong-Seung
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.61-64
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    • 2007
  • Ni/YSZ ($Y_{2}O_{3}-stabilized$ $ZrO_{2}$), Cu/YSZ and CuO/YSZ composite powder for a cathode material in high temperature electrolysis (HTE) was synthesized by a mechanical alloying method with Ni (or Cu, CuO, Co) and YSZ powder. Microstructure of the composite for HTE reaction has been analyzed with various techniques of XRD, SEM to investigate effects of fabrication conditions. And conductivity of electrode was measured, Cu/YSZ cermet showed the higher electrical conductivity value than Ni/YSZ.

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Comparison of the Power Generating Characteristics of KIST- and FZ-Julich SOFCs (KIST와 FZ-Julich SOFC간의 출력성능 비교)

  • Jung, Hwa-Young;Lee, Sang-Cheol;Tietz, Frank;Kim, Hae-Ryoung;Lee, Hae-Weon;Lee, Jong-Ho
    • Journal of the Korean Ceramic Society
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    • v.44 no.12
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    • pp.703-709
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    • 2007
  • We evaluate and compare the power generating characteristics of the anode supported SOFCs which have been fabricated from KIST and FZ-Julich in Germany. The performance and electrochemical property of each unit cell was characterized at the temperature range of $650-850^{\circ}C$ under same operating conditions and its microstructural property was thoroughly investigated via SEM after the performance test. According to the investigation, KIST- and FZJ SOFC showed different power generating characteristics in their temperature dependances due to their different design of electrode microstructure, especially the cathode microstructure. FZJ SOFC showed better performance at high temperature while showed lower performance at lower temperature. From the investigation about the correlation between microstructure and electrochemical property, we found that the superior performance of FZJ SOFC at high temperature was mainly due to its lower cathodic polarization resistance whereas better performance of KIST SOFC at lower temperature was mostly attributed to the lower ohmic resistance.

Alternative Sample Preparation Method for Large-Area Cross-Section View Observation of Lithium Ion Battery

  • Kim, Ji-Young;Jeong, Young Woo;Cho, Hye Young;Chang, Hye Jung
    • Applied Microscopy
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    • v.47 no.2
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    • pp.77-83
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    • 2017
  • Drastic development of ubiquitous devices requires more advanced batteries with high specific capacitance and high rate capability. Large-area microstructure characterization across the stacks of cathode, electrolyte and anode might reveal the origin of the instability or degradation of batteries upon cycling charge. In this study, sample preparation methods to observe the cross-section view of the electrodes for battery in SEM and several imaging tips are reviewed. For an accurate evaluation of the microstructure, ion milling which flats the surface uniformly is recommended. Pros and cons of cross-section polishing (CP) with Ar ion and focused ion beam (FIB) with Ga ion were compared. Additionally, a modified but new cross-section milling technique utilizing precision ion polishing system (PIPS) which can be an alternative method of CP is developed. This simple approach will make the researchers have more chances to prepare decent large-area cross-section electrode for batteries.

Effect of Ti Adhesion Layer on the Electrical Properties of BMNO Capacitor Using Graphene Bottom Electrodes (그래핀 하부전극을 이용하여 BMNO 케페시터의 특성 향상을 위한 Ti Adhesion Layer의 효과)

  • Park, Byeong-Ju;Yoon, Soon-Gil
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.12
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    • pp.867-871
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    • 2013
  • The Ti adhesion layers were deposited onto the glass substrate for transparent capacitors using $Bi_2Mg_{2/3}Nb_{4/3}O_7$ (BMNO) dielectric thin films. Graphene was transferred onto the Ti/glass substrate after growing onto the Ni/$SiO_2$/Si using rapid-thermal pulse CVD (RTPCVD). The BMNO dielectric thin films were investigated for the microstructure, dielectric and leakage properties in the case of capacitors with and without Ti adhesion layers. Leakage current and dielectric properties were strongly dependent on the Ti adhesion layers grown for graphene bottom electrode.

Microstructural Properties of PZT Heterolayered Thin Films Prepared by Sol-Gel Method (솔-젤법으로 제작한 PZT 이종층 박막의 구조적 특성)

  • 이성갑;김경태;정장호;박인길;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.311-314
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    • 1999
  • Ferroelectric PZT heterolayered thin films were fabricated by spin coating method on the Pt/Ti/SiO$_2$/Si substrate using PZT(10/90) and PZT(90/10) metal alkoxide solutions. All PZT heterolayered films showed a homogeneous grain structure without presence of the rosette structure. It can be assumed that the lower PZT layers a role of nucleation site or seeding layer for the formation of the upper PZT layer. Zr and Ti diffusion into the Pt electrode were mainly distributed at the surface of Pt electrode beneath the PZT/Pt interface. The PZT/Pt interfacial layer showed a microstructure characterized by a grain phase surrounded by a Pb-deficient pyrochlore matrix phase. The relative dielectric constant and the dielectric loss of the PZT-6 film were 567 and 3.6, respectively.

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A Study on Structural and Electrical Properties of ZnO Thick Films on the Glass Substrate and PET Film (Glass Substrate와 PET Film위에 Screen Printing된 ZnO Thick Film의 구조적 전기적 특성)

  • Lee, Ku-Tak;Jeon, Min-Cheol;Chae, Moon-Soon;Lee, Kyung-Ju;Moon, Byung-Moo;Koh, Jung-Hyuk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.5
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    • pp.355-358
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    • 2011
  • As a II-IV compound semiconductor, ZnO has a wide band gap of 3.37 eV with transparent properties. Due to this transparent properties, ZnO materials can be also employed as the transparent conducting electrode materials. Recently, rapid progress has been made in the field of DSSC (dye sensitized solar cell)area. Therefore, strong demands have been required for the transparent electrodes with low temperature processing and cheap cost. In this paper, we will prepare ZnO thick films on the PET substrates for the electrode applications. We will investigate the structural and microstructure properties through the XRD, and SEM analysis, respectively. Also, we will study the electrical of specimens to apply the conducting electrode.

Bending Properties of the Flexible BMNO (Bi2Mg2/3Nb4/3O7) Capacitor Using Graphene Electrode (그래핀 전극을 이용한 유연한 BMNO (Bi2Mg2/3Nb4/3O7) 캐패시터의 굽힘 특성)

  • Song, Hyun-A;Park, Byeong-Ju;Yoon, Soon-Gil
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.5
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    • pp.387-391
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    • 2012
  • Graphene was fabricated onto Ni/Si substrate using a rapid-thermal pulse CVD and they were transferred onto the Ti/PES flexible substrate. For top electrode applications of the BMNO dielectric films, graphene was patterned using a argon plasma. Through an AFM image and a leakage current density of the BMNO films grown onto various bottom electrodes before and after bending test, BMNO films grown onto the graphene bottom electrode showed no change of the microstructure and the leakage current density after the bend.

Effects of 27.12 MHz Radio Frequency on the Rapid and Uniform Tempering of Cylindrical Frozen Pork Loin (Longissimus thoracis et lumborum)

  • Choi, Eun Ji;Park, Hae Woong;Yang, Hui Seon;Kim, Jin Se;Chun, Ho Hyun
    • Food Science of Animal Resources
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    • v.37 no.4
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    • pp.518-528
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    • 2017
  • Quality characteristics of frozen cylindrical pork loin were evaluated following different tempering methods: 27.12 MHz curved-electrode radio frequency (RF) at 1000 and 1500 W, and forced-air convection (FC) or water immersion (WI) at $4^{\circ}C$ and $20^{\circ}C$. The developed RF tempering system with the newly designed curved-electrode achieved relatively uniform tempering compared to a parallel-plate RF system. FC tempering at $4^{\circ}C$ was the most time-consuming process, whereas 1500 W RF was the shortest. Pork sample drip loss, water holding capacity, color, and microbiological quality declined after WI tempering at $20^{\circ}C$. Conversely, RF tempering yielded minimal sample changes in drip loss, microstructure, color, and total aerobic bacteria counts, along with relatively uniform internal sample temperature distributions compared to those of the other tempering treatments. These results indicate that curved-electrode RF tempering could be used to provide rapid defrosting with minimal quality deterioration of cylindrical frozen meat block products.

Dielectric and Electrical Properties of $Sr_{0.9}Bi_{2+x}Ta_2O_9$ Thin Films on $IrO_2$ Electrode ($IrO_2$를 하부전극으로 사용한 $Sr_{0.9}Bi_{2+x}Ta_2O_9$ 박막의 유전 및 전기적 특성)

  • 박보민;송석표;정병직;김병호
    • Journal of the Korean Ceramic Society
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    • v.37 no.3
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    • pp.233-239
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    • 2000
  • Sr0.9Bi2+xTa2O9(x=0, 0.1, 0.2, 0.3) thin films on IrO2/SiO2/Si or Pt/Ti/SiO2/Si substrate were prepared by spin coating method using SBT stock solutions synthesized by MOD process. SBT thin films on IrO2 transformed to layered perovskite phase at $700^{\circ}C$, but showed low breakdown voltage due to their porous microstructure. The smaple of Sr0.9Bi2+xTa2O9 composition showed the best dielectric and electrical properties. When the sample of the same composition was annealed at 80$0^{\circ}C$, the dielectric and electric properties were improved due to the grian growth and dense surface. the remanent polarization values(2Pr) at $\pm$3 V for IrO2 and Pt electrodes were 10.5, 7.15$\mu$C/$\textrm{cm}^2$, respectively. The SBT thin film with IrO2 electrode showed the lower coercive field. The leakage current density and breakdown voltage of SBT thin films on IrO2 were higher than those on Pt.

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Effect of Thermal Treatment Temperature on Electrochemical Behaviors of Ni/trimesic Acid-based Metal Organic Frameworks Electrodes for Supercapacitors (수퍼커패시터용 니켈/트리메식 산 기반 금속-유기구조체 전극의 전기화학적 거동에 열처리 온도가 미치는 효과)

  • Kim, Jeonghyun;Jung, Yongju;Kim, Seok
    • Applied Chemistry for Engineering
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    • v.30 no.1
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    • pp.11-16
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    • 2019
  • Ni-benzene-1,3,5-tricarboxylic acid based metal organic frameworks were successfully synthesized by hydrothermal method and thermally treated at various temperature. The electrochemical performance of composites was investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Among all prepared composites, the samples annealed at $250^{\circ}C$ showed the highest capacitance with a low resistance, and high cycle stability. It was possible to obtain the low electrical resistance and high electric conductivity of the electrode by improved microstructure and morphology after the thermal annealing at $250^{\circ}C$. The samples annealed at $250^{\circ}C$ also displayed the maximum specific capacitance with a value of $953Fg^{-1}$ at a current density of $0.66A/g^{-1}$ in 6 M KOH electrolyte. Moreover, a 86.4% of the initial specific capacitance of the composite was maintained after 3,000 times charge-discharge cycle tests. Based on these properties, it can be concluded that the composite could be applied as potential supercapacitor electrode materials.