• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.169-169
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• 2017

Due to key roles for the electrochemical stability and charge capacity the solid-electrolyte interphase (SEI) has been extensively studied in anodes of a Li-ion battery cell. There is, however, few of investigation for cathodes. Using first-principles based calculations we describe atomic-level process of the SEI layer formation at the interface of a carbonate electrolyte and $LiMn_2O_4$ spinel cathode. Furthermore, using beyond the conventional density functional theory (DFT+U) calculations we examine the work function of the cathode and frontier orbitals of the electrolyte. Based on the results we propose that proton transfer at the interface is an essential mechanism initiating the SEI layer formation in the $LiMn_2O_4$. Our results can guide a design concept for stable and high capacity Li-ion battery cell through screening an optimum electrolyte fine-tuned energy band alignment for a given cathode.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1995.10a
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• pp.105-109
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• 1995

In this paper, we persents a new PAM method without the input transformer for reducing harmonics in input AC line currents of converter. This system can reduce the harmonics like conventional 12-pulse converter. the dual bridge circuits are controlled with the shifted firing angle and connected 2 tap interphase reactor. the input current using 2 tap changing on interphase reactor is controlled with the different two values in order to make the input current waveform 12 pulses. The chracteristics of this system were confirmed through the computer simulation and the experiments.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.105-108
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• 2011

The cycling behavior of $Li_4Ti_5O_{12}$ electrode in the ionic liquid (IL)-based electrolytes containing 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide and a small amount of additive (vinylene carbonate, ethylene carbonate, fluoroethylene carbonate) was investigated. The $Li_4Ti_5O_{12}$ electrode in the IL electrolyte with an additive exhibited reversible cycling behavior with good capacity retention. Electrochemical impedance spectroscopy and FTIR studies revealed that an electrochemically stable solid electrolyte interphase was formed on the $Li_4Ti_5O_{12}$ electrode in the presence of vinylene carbonate and ethylene carbonate during cycling.

• Ceramist
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• v.9 no.6
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• pp.18-23
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• 2006

In this article, the present activities regarding research and development of continuous SiC fiber reinforced ceramic matrix composites (CFCC) in Japan are reviewed. The key technologies in SiC fiber composites are interphase between fiber and matrix and its oxidation resistance. To improve oxidation resistance of interphase, various kinds of technologies such as environment barrier coating, high dense matrix, unti-oxidation matrix, multi-layered intephase have been developed. It is suggested that high performance, affordable processing cost, and excellent reliability will be important factors to be in practical use of CMCs in future.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.11
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• pp.640-645
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• 1999

This paper proposes a new series-connected diode rectifier which draws sinusoidal input currents. The proposed rectifier system is configured by adding an auxiliary circuit to the conventional 12-pulse series-connected diode rectifier and employing a current injection technique. A low kVA($0.02P_{\circ}$(PU) ) active current source injects a triangular current into the interphase reactor of the diode rectifier. The current injection results in near sinusoidal input current from the utility with less than 1% THD. The resulting system is suitable for high voltage and high power applications. Experimental and simulation results are provided from a 220V, 3kVA prototype rectifier system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.1
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• pp.25-32
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• 1988

In this paper, a new method for reducing harmonics in input AC line currents of converter is presented, which is due mainly to the equipment of 2-4 switching taps on interphase reactor. When this method is applicable to conventional 12 pulse converter, the 24 pulse converter, the 24 pulse or 48 pulse converter is controlled by firing angles. The former is performe in 2 tap method when less than 15 degrees, and the letter in 4tap method when more than 15 degrees. Therefore, the proposed method has the advantages of reducing harmonics in full range of control angle and comparison with the conventional 3 tap method. We proved the validity of that theoretically and experimentally.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.506-509
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• 2001

A high power U.P.S system utilizing the parallel connection of low power U.P.S is developed. For the purpose of elimination the circular current between U.P.S.s, a digital circuit is employed. Furthermore a double phase synchronization and an interphase reactor are used to eliminate the circular current and the voltage ripples caused by the system parameter unbalances of parall connected U.P.S.s. The digital controller is implemented with ADSP21061 as aspect of a functional convenience.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.565-572
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• 2013

The fabrication methods and requirements of the fiber, interphase, and matrix of nuclear grade $SiC_f/SiC$ composites are briefly reviewed. A CVI-processed $SiC_f/SiC$ composite with a PyC or $(PyC-SiC)_n$ interphase utilizing Hi-Nicalon Type S or Tyranno SA3 fiber is currently the best combination in terms of the irradiation performance. We also describe important material issues for the application of SiC composites to LWR fuel cladding. The kinetics of the SiC corrosion under LWR conditions needs to be clarified to confirm the possibility of a burn-up extension and the cost-benefit effect of the SiC composite cladding. In addition, the development of end-plug joining technology and fission products retention capability of the ceramic composite tube would be key challenges for the successful application of SiC composite cladding.

• Journal of Industrial Technology
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• v.43 no.1
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• pp.43-48
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• 2023

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) has been considered as one of most promising cathode material, because of its low-cost and competitive energy density. However, 4.7V vs. Li/Li⁺ of high operating potential facilitates electrolyte degradation on cathode-electrolyte interface during charge-discharge process. In particular, commercial polyvinylidene fluoride (PVDF) is not sutaible for LNMO cathode binder because its weak van der waals force induces thick and non-uniform coverage on the cathode surface. In this review, we study high performance binders for LNMO cathode, which forms uniform coating layer to prevent direct contact between electrolyte and LNMO particle as well as modifying high quality cathode electrolyte interphase, improved cell performace.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.295-300
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• 2012

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.