• 한국분말재료학회지
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• 제22권1호
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• pp.15-20
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• 2015

The composite of porous silicon (Si) and amorphous carbon (C) is prepared by pyrolysis of a nano-porous Si + pitch mixture. The nano-porous Si is prepared by mechanical milling of magnesium powder with silicon monoxide (SiO) followed by removal of MgO with hydrochloric acid (etching process). The Brunauer-Emmett-Teller (BET) surface area of porous Si ($64.52m^2g^{-1}$) is much higher than that before etching Si/MgO ($4.28m^2g^{-1}$) which indicates pores are formed in Si after the etching process. Cycling stability is examined for the nano-porous Si + C composite and the result is compared with the composite of nonporous Si + C. The capacity retention of the former composite is 59.6% after 50 charge/discharge cycles while the latter shows only 28.0%. The pores of Si formed after the etching process is believed to accommodate large volumetric change of Si during charging and discharging process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.453-454
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• 2016

The ESS(Energy Storage System) connected with distributed generation is drawing attention due to improving the quality load leveling, peak shaving for enhancing reliability of the power grid. The grid-connected inverter makes frequency adjustment to the active power's charge discharge according to the load variation. In addition, the inverter is possible to act as a reactive power compensation device to eliminate harmonic operates as power factor change inhibiting, anti-transient voltage fluctuation, active filter. In this paper, we propose a design method of igbt stack considering the reactive power supply capacity to improve the quality and reliability of the inverter. Moreover, the grid-connected inverter considering the four-quadrant rated operation designed stack and verified the feasibility of the design through a thermal analysis.

• 한국응용과학기술학회지
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• 제21권2호
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• pp.164-173
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• 2004

The capacity and long life of gel electrolyte batteries is connected with gas recombination producting $PbO_2$ and Pb electrode. We prepared with sulfuric acid gel electrolyte to know gel characteristics per density to assemble valve regulated lead-acid (VRLA) batteries. We studied on actions of sulphuric acid gel electrolyte by measuring electrolyte dispersion using Brewster-angle microscope (BAM), charge-discharge cycle, and electrode structure using scanning election microscope (SEM). Sulphuric acid density 1.210 showed excellent gel dispersion in sol condition, electrode condition after fifty cycles in this study.

• 전기화학회지
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• 제10권2호
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• pp.88-93
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• 2007

Nano-sized Sn particles were coated with Ni-P layer using an electroless deposition method and their anodic performance was tested for lithium secondary batteries. Uniform coating layers were obtained, of which the thickness was controlled by varying the $Ni^{2+}$ concentration in the plating bath. It was found that the Ni-P layer plays two important roles in improving the anodic performance of Sn powder electrode. First, it prevents the inter-particle aggregation between Sn particles during the charge/discharge process. Second, it provides an electrical conduction pathway to the Sn particles, which allows an electrode fabrication without an addition of conductive carbon. A pseudo-optimized sample showed a good cyclability and high capacity ($>400mAh\;g^{-1}$) even without conductive carbon loading.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.421-423
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• 2006

In this paper, we propose EDLC's high effective operating techniques. EDLC is energy storage device that has advantages of electrolytic capacitor and accumulation capacitor and that supplements defect such as energy storing accumulation capacity, life time and safety. But, EDLC needs for more complex control scheme because is influenced directly in efficiency and life time by charge and discharge control method. In this paper, DVR system's performance is proposed by EDLC's high effective operating technique.

• 한국응용과학기술학회지
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• 제20권4호
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• pp.296-308
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• 2003

The capacity and long life of gel electrolyte batteries is connected with gas recombination producting $PbO_2$ and Pb electrode. We were prepared with phosphoric acid gel electrolyte to know gel characteristics per density to assemble VRLA batteries. We studied by measuring electrolyte dispersion using Brewster-angle microscope(BAM), charge-discharge cycle and electrode structure using scanning election microscope(SEM) per electrolyte density. As a results, phosphoric acid density 1.210 was excellent gel dispersion in sol condition, electrode condition after fifty cycles in this study.

• 한국전기전자재료학회논문지
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• 제11권9호
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• pp.727-732
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• 1998

Ag-deposited graphite powder was prepared by a chemical reduction method of metal particles onto graphite powder. X-ray diffraction observation of Ag-deposited graphite powder revealed that silver existed in a metallic state, but not in an oxidized one. From SEM measurement, ultrafine silver particles were highly dispersed on the surface of graphite particles. Cylindrical lithium ion secondary battery was manufactured using Ag-deposited graphite anodes and $LiCoO_2$ cathodes. The cycleability of lithium ion secondary battery using Ag-deposited graphite anodes was superior to that of original graphite powder. The improved cycleability may be due to both the reduction of electric resistance between electrodes and the highly durable Ag-graphite anode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.289-289
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• 2007

Spinel structured $LiMn_2O_4$ is more economic and environmental friendly to be used as commercial active material for secondary battery compared to Co-oxide material active material, but spinel structure of $LiMn_2O_4$ is unstable and its capacitance decreases with increase of cycle. Therefore, the purpose of our sturdy is to improve the stability of $LiMn_2O_4$ spinel structure and increase its capacitance by using substituents or dopants. $LiMn_2O_4$ powder was synthesized by charging substituents or dopants mole fractions, and temperatures. Crystal state, structure and specific surface area of the synthesized powder were measured and also characteried electrochemically by measuring its impedance, charge-discharge capacitance and etc.

• Journal of Electrochemical Science and Technology
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• 제9권4호
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• pp.301-307
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• 2018

The current study fabricated magnetic functional reduced graphene oxide (MFRGO) by relying on ${FeCl_4}^-$ magnetic anion confined to cationic 1-methyl imidazolium. Furthermore, for improving the electrochemical performance of conductive polymer, hybrid poly ortho aminophenol (POAP)/ MFRGO films have then been fabricated by POAP electropolymerization in the presence of MFRGO nanorods as active electrodes for electrochemical supercapacitors. Surface and electrochemical analyses have been used for characterization of MFRGO and POAP/ MFRGO composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. Prepared composite film exhibited a significantly high specific capacity, high rate capability and excellent cycling stability (capacitance retention of ~91% even after 1000 cycles). These results suggest that electrosynthesized composite films are a promising electrode material for energy storage applications in high-performance pseudocapacitors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.124-126
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• 2020

다양한 기기에 적용된 리튬 이온 전지의 출력은 전력으로 계산되며, 리튬 이온 전지는 전류 기반의 해석뿐만 아니라 전력기반의 해석 또한 필수적이다. 본 논문은 리튬 이온 전지의 정전력 입력과 출력에 따른 전류 관점의 분석과 전력 관점의 분석을 수행하였다. 리튬 이온 전지에서 정전력 입력 및 출력 시, 충전 상태와 에너지 상태 변화의 차이를 및 용량과 에너지 변화를 분석하였다.