• Title/Summary/Keyword: anode materials

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TiN Anode for Electrolytic Reduction of UO2 in Pyroprocessing (TiN 양극을 이용한 파이로프로세싱 UO2 전해환원)

  • Kim, Sung-Wook;Choi, Eun-Young;Park, Wooshin;Im, Hun Suk;Hur, Jin-Mok
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.13 no.3
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    • pp.229-233
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    • 2015
  • Developing novel anode materials to replace the Pt anode currently used in electrolytic reduction is an important issue on pyroprocessing. In this study, the electrochemical behavior of TiN was investigated as the conductive ceramic anode which evolves O2 gas during the reaction. The feasibility and stability of the TiN anode was examined during the electrolytic reduction of UO2. The TiN anode could electrochemically convert UO2 to metallic U in a LiCl–Li2O molten salt electrolyte. No oxidation of TiN was observed during the reaction; however, the formation of voids in the bulk section appeared to limit the lifetime of the TiN anode.

Effect of Target Angle and Thickness on the Heel Effect and X-ray Intensity Characteristics for 70 kV X-ray Tube Target

  • Kim, Gyehong;Lee, Rena
    • Progress in Medical Physics
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    • v.27 no.4
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    • pp.272-276
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    • 2016
  • To investigate the optimum x-ray tube design for the dental radiology, factors affecting x-ray beam characteristics such as tungsten target thickness and anode angle were evaluated. Another goal of the study was to addresses the anode heel effect and off-axis spectra for different target angles. MCNPX has been utilized to simulate the diagnostic x-ray tube with the aim of predicting optimum target angle and angular distribution of x-ray intensity around the x-ray target. For simulation of x-ray spectra, MCNPX was run in photon and electron using default values for PHYS:P and PHYS:E cards to enable full electron and photon transport. The x-ray tube consists of an evacuated 1 mm alumina envelope containing a tungsten anode embedded in a copper part. The envelope is encased in lead shield with an opening window. MCNPX simulations were run for x-ray tube potentials of 70 kV. A monoenergetic electron source at the distance of 2 cm from the anode surface was considered. The electron beam diameter was 0.3 mm striking on the focal spot. In this work, the optimum thickness of tungsten target was $3{\mu}m$ for the 70 kV electron potential. To determine the angle with the highest photon intensity per initial electron striking on the target, the x-ray intensity per initial electron was calculated for different tungsten target angles. The optimum anode angle based only on x-ray beam flatness was 35 degree. It should be mentioned that there is a considerable trade-off between anode angle which determines the focal spot size and geometric penumbra. The optimized thickness of a target material was calculated to maximize the x-ray intensity produced from a tungsten target materials for a 70 keV electron energy. Our results also showed that the anode angle has an influencing effect on heel effect and beam intensity across the beam.

H2S tolerance effects of Ce0.8Sm0.2O2-δ modification on Sr0.92Y0.08Ti1-xNixO3-δ anode in solid oxide fuel cells

  • Kim, Kab In;Kim, Hee Su;Kim, Hyung Soon;Yun, Jeong Woo
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.187-195
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    • 2018
  • $Sr_{0.92}Y_{0.08}Ti_{1-x}Ni_xO_{3-{\delta}}$ (SYTN) was investigated in the presence of $H_2S$ containing fuels to assess the feasibility of employing oxide materials as alternative anodes. Aliovalent substitution of $Ni^{2+}$ into $Ti^{4+}$ increased the ionic conductivity of perovskite, leading to improved electrochemical performance of the SYTN anode. The maximum power densities were 32.4 and $45.3mW/cm^2$ in $H_2$ at $900^{\circ}C$ for the SYT anode and the SYTN anode, respectively. However, the maximum power densities in 300 ppm of $H_2S$ decreased by 7% and by 46% in the SYT and the SYTN anodes, respectively. To enhance the sulfur tolerance and to improve the electrochemical properties, the surface of SYTN anode was modified with samarium doped ceria (SDC) using the sol-gel coating method. For the SDC-modified SYTN anode, the cell performance was mostly recovered in the pure $H_2$ condition after 500-ppm $H_2S$ exposure in contrast to the irreversible cell performance degradation exhibited in the unmodified SYTN anode.

Electrical and Mechanical Characteristics of Ni-YSZ Tubular Support Fabricated by Extrusion (압출공정에 의해 제조된 Ni-YSZ 원통형 음극 지지체의 특성)

  • Yu, Ji-Haeng;Kim, Young-Woon;Park, Gun-Woo;Seo, Doo-Won;Lee, Shi-Woo;Woo, Sang-Kuk
    • Journal of the Korean Ceramic Society
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    • v.43 no.12 s.295
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    • pp.768-774
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    • 2006
  • The microstructure of Ni-YSZ cermets was controlled with fine and coarse starting powders (NiO and YSZ) to obtain a optimum strong and conductive tubular anode support for SOFCs. Three types of cermets with different microstructures, i.e., coarse Ni-fine YSZ, fine Ni-coarse YSZ, and fine Ni-fine YSZ, were fabricated to investigate their electrical and mechanical properties. The cermets from fine NiO powder showed high electrical conductivity due to the enhanced percolation of Ni particles. The cermet by foe Ni and coarse YSZ showed excellent electrical conductivity (>1000 S/cm) despite its high porosity $(\sim40%)$ but it showed poor mechanical strength due to the lack of percolation by YSZ particles and due to large pores. Thus fine NiO and YSZ powders were used to make strong and conductive Ni-YSZ support tube by extrusion. The microstructure of the anode tube was modified by the amount of polymeric additives and carbon black, a pore former. Ni-YSZ tube (porosity $\sim34%$) with the finer microstructure showed better performance both in electrical conductivity (>1000 S/cm) and fracture strength $(\sim140\;MPa)$. Either flat or circular NiO-YSZ tubes with the length from 20 to 40cm were successfully fabricated with the optimized composition of materials and polymeric additives.

Synthesis of Various Biomass-derived Carbons and Their Applications as Anode Materials for Lithium Ion Batteries (다양한 바이오매스 기반의 탄소 제조 및 리튬이온전지 음극활물질로의 응용)

  • Chan-Gyo Kim;Suk Jekal;Ha-Yeong Kim;Jiwon Kim;Yeon-Ryong Chu;Hyung Sub Sim;Chang-Min Yoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.31 no.3
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    • pp.27-34
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    • 2023
  • In this study, various plant-based biomass are recycled into carbon materials to employ as anode materials for lithium-ion batteries. Firstly, various biomass of rice husk, chestnut, tea bag, and coffee ground are collected, washed, and ground. The carbonization process is followed under a nitrogen atmosphere at 850℃. The morphological and chemical properties of materials are investigated using FE-SEM, EDS, and FT-IR to compare the characteristic differences between various biomass. It is noticeable that biomass-derived carbon materials vary in shape and degree of carbonization depending on their precursor materials. These materials are applied as anode materials to measure the electrochemical performance. The specific capacities of rice husk-, chetnut-, tea bag-, and coffee ground-derived carbon materials are evaluated as 65.8, 80.2, 90.6, and 104.7 mAh g-1 at 0.2C. Notably, coffee ground-based carbon exhibited the highest specific capacity owing to the difference in elemental composition and the degree of carbonization. Conclusively, this study suggests the possibility of utilizing as energy storage devices by employing various plant-based biomass into active materials for anodes.