• Journal of Electrochemical Science and Technology
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• 제2권3호
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• pp.180-185
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• 2011

The layered lithium-manganese oxide ($Li_2MnO_3$) as a cathode material of lithium ion secondary batteries was prepared and characterized the physico-chemical and electrochemical properties. The morphological and structural changes of MnO(OH) and $Li_2MnO_3$ are closely connected to the changes of electrochemical properties. The crystallinity of $Li_2MnO_3$ is enhanced as the annealing temperature increase, but its capacity is reduced due to the easier structural changes of less crystalline $Li_2MnO_3$ than highly crystalline one. Moreover, the addition of buffer material such as MnO(OH) into cathode causes to reduce the morphological and structural changes of layered $Li_2MnO_3$ and increase the discharge capacity and cycleability.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.46-46
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• 2007

There has been rapid progress in the portable electronics industry. which has led to a great increase for a demand of portable, lightweight power sources. Lithium 2'nd batteries have met these demand. and many studies on the cahtod materials for the lithium 2,nd batteries have been reported during the last decade. Possible candidates for the cathode materials for lithium 2,nd batteries are $LiCoO_2$, $LiNiO_2$, and $LiMn_2O_4$. Currently $LiCoO_2$ is widely used. but $LiMn_2O_4$ is an excellent alternative material in view of its several advantages such a low cost as well as the wasy availability of raw materials and environmental benignity. In this study, find the most suitable synthesis method that satisfied high capacitor and stability cycle character, etc in Li-Mn oxide for 2'nd batteries. And also made an experiment on doping the $LiMn_2O_4$ spinel with a small amount of metal ions has a remarkable effect on the electrochemical properties and characterics of powder, BET, PSA, Porosity, etc.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.180-186
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• 2018

We report the discovery of Li-rich $Li_{1+x}[(Ni_{0.225}Co_{0.15}Mn_{0.625})_{1-y}V_y]O_2$ as a cathode material for rechargeable lithium-ion batteries in which a small amount of tetravalent vanadium ($V^{4+}$) is selectively and completely incorporated into the manganese sites in the lattice structure. The unwanted oxidation of vanadium to form a $V_2O_5-like$ secondary phase during high-temperature crystallization is prevented by uniformly dispersing the vanadium ions in coprecipitated $[(Ni_{0.225}Co_{0.15}Mn_{0.625})_{1-y}V_y](OH)_2$ particles. Upon doping with $V^{4+}$ ions, the initial discharge capacity (>$275mA\;h\;g^{-1}$), capacity retention, and voltage decay characteristics of the Li-rich layered oxides are improved significantly in comparison with those of the conventional undoped counterpart.

• 대한화학회지
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• 제37권9호
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• pp.837-844
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• 1993

N-Arylmethylideneglycine N-oxide alkyl esters(1)를 THF 용매내에서 lithium hexamethyldisilazide로 처리한 다음 할로겐화 알킬과 반응시켜 알킬화하고 이를 히드록실아민으로 분해시켜 N-hydroxy-${\alpha}$-amino acid esters(7)를 합성하였다.

• Journal of Electrochemical Science and Technology
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• 제11권4호
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• pp.399-405
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• 2020

Hollow copper oxide/multi-walled carbon nanotubes (CuO/MWCNT) composites were fabricated via an optimized infiltration-reduction-oxidation method, which is more facile and easy to control. The crystalline structure and morphology were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The as-prepared CuO/MWCNT composites deliver an initial capacity of 612.3 mAh·g^-1 and with 80% capacity retention (488.2 mAh·g^-1) after 100 cycles at a current rate of 0.2 A·g^-1. The enhanced electrochemical performance is ascribed to the better electrical conductivity of MWCNT, the hollow structure of CuO particles, and the flexible structure of the CuO/MWCNT composites.

• 한국재료학회지
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• 제12권4호
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• pp.240-247
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• 2002

Tin oxide thin films doped with silicon as anodes for lithium secondary battery were fabricated by R.F. magnetron sputtering technique. The electrochemical results showed that the irreversible capacity was reduced during the first discharge/charge cycle, because the audition of silicon decreased the oxidic state of Tin. Capacity was increased with the increase of substrate temperature, however decreased with the increase of RTA temperatures. The reversible capacity of thin films fabricated under the substrate temperature of $300^{\circ}C$ and the Ar:$O_2$ratio of 7:3 was 700mA/g.

• 대한전자공학회논문지
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• 제24권3호
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• pp.510-516
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• 1987

An analysis and numerical computations relating to the coupling of optical modes between two neighboring waveguides are discussed. The waveguides are fabricated with Lithium Niobate as guide 1 and Vanadium Oxide as guide 2. In a wave guide system that incorporates two lossless guides, a complete transfer of power from one guide to another can occur when the waveguides are (1) identical or (2) the modes in each guide have identical phase constants. Here we discuss the coupling effects when the guides are dissimilar with respect to both geometry and losses. In thers results, we show that power transfer can occur between the two guides, one lossy and the other lossless, provided the phase matched condition is satisfied. When properly coupled, the power attenuation varies according to the amount of coupling.

• Journal of the Optical Society of Korea
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• 제1권1호
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• pp.19-22
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• 1997

The photorefractive properties of 4% mol magnesium oxide doped lithium niobate have been investigated at room temperature. The recording and erasing time constants were measured as a function of intensity and analyzed by using the two active species (electron-hole) model. The results were used to compute the exposure schedule for multiple hologram recording. We have recorded grating of five holograms by angular multiplexing at room temperature and fixed them by means of a thermal cycling procedure. The highest diffraction efficiency of a fixed grating is up to 50% of an unfixed one.

• Nuclear Engineering and Technology
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• 제35권4호
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• pp.309-317
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• 2003

The mass balance of the unit processes of the Advanced spent fuel Conditioning Process was calculated to obtain basic information. Based on this mass balance, the changes in decay heat and radioactivity of the spent fuel due to the metallization in the high temperature molten salt system were estimated. The decay heat and the radioactivity were calculated by using the ORIGEN2 computer code, and the result showed that the decay heat and the radioactivity of the metallized spent fuel ingot were $24.27\%\;and\;24.24\%$, respectively, compared to those of oxide spent fuel.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.257-260
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• 2014