• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.752-756
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• 2002

Green-emitting $Zn_2SiO_4:Mn$ phosphors for PDP(Plasma Display Panel) application were synthesized by colloidal seed-assisted spray pyrolysis process. The codoping with $Gd^{3+}/Li^+$, which replaces $Si^{4+}$ site in the willemite structure, was performed to improve the luminous properties of the $Zn_2SiO_4:Mn$ phosphors. The particles prepared by spray pyrolysis process using fumed silica colloidal solution had a spherical shape, small particle size, narrow size distribution, and non-aggregation characteristics. The $Gd^{3+}/Li^+$ codoping amount affected the luminous characteristics of $Zn_2SiO_4:Mn$ phosphors. The codoping with proper amounts of $Gd^{3+}/Li^+$ improved both the photoluminescence efficiency and decay time of $Zn_2SiO_4:Mn$ phosphor particles. In spray pyrolysis, the post-treatment temperature is another factor controlling the luminous performance of $Zn_2SiO_4:Mn$ phosphors. The $Zn_{1.9}SiO_4:Mn_{0.1}$ phosphor particles containing 0.1 mol% $Gd^{3+}/Li^+$ co-dopant had a 5% higher PL intensity than the commercial product and 5.7 ms decay time after post-treatment at $1,145^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.18-22
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• 2001

Spinel $LiMn_{2-y}Mn_{y}O_4$ powder was prepared solid-state method by calcining the mixture of $LiOH{\cdot}H_2O$, $MnO_2$ and MgO at $800^{\circ}C$ for 36h. To investigate the effect of temperature for cycle behaviour of cathode material during cycling, charge-discharge experiments and initial impedance spectroscopy performed by the condition of the charge-discharge temperature. Initial charge-discharge capacity was gradually increased by rising charge-discharge temperature. However, capacity was suddenly decreased at high temperature during cycling. Capacity at low temperature was almost constant during cycling. It confirmed because Mn dissolution is more serious at high temperature than at low temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.1029-1035
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• 2008

$LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ cathode materials prepared from different precursors in lithium rechargeable batteries were characterized by various analytical methods. $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ powders were synthesized by using solid-state reaction method and their physical and chemical properties were analyzed by XRD, SEM, particle size analyzer and TCP-AES. These materials showed different crystallinity, particle size, surface morphology and chemical composition. Also, the charge/discharge cycling of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ electrodes was carried out under various cut-off voltages and it showed different behaviors. It was found that the electrochemical cyclability of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ was strongly related to its crystallinity.

• 한국전기화학회:학술대회논문집
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• 1999.10a
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• pp.57-57
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• 1999

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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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.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1462-1464
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• 1997

The spinel $LiMn_2O_4$ has been synthesized by solid-state reaction. $LiMn_2O_4$ which includes 3 mix $Li_2CO_3$ or $LiNO_3$ and $MnO_2$ prepared by Prelim heating at $350^{\circ}C$ for 24hr. $LiMn_2O_4$ fired at temp range from $600^{\circ}C$ to $800^{\circ}C$ for 48hr. The structure a electrochemical characteristics of spinel $LiMn_2O_2$ wh fabricated by changing sintering condition from st materials are investigated. The spinel $LiMn_2O_4$ prepared by the mixture of L CMD at $800^{\circ}C$ for 48hr showed an initial charge ca of 146mAh/g. The spinel $LiMn_2O_4$ prepared by the m of $LiNO_3$/CMD at $600{\sim}800^{\circ}C$ for 48hr stabilized ch discharge capacity after 50th cycles.

• Journal of the Korean Electrochemical Society
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• v.11 no.3
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• pp.197-210
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• 2008

The cathode materials for lithium ion battery have been developed in accordance with the battery performance. $LiCoO_2$ initially adapted at lithium ion battery is going to be useful even at the charging voltage of 4.3 V by surface treatment or doping which drastically improved the performance of $LiCoO_2$. On the other hand, the complicate and multiple functions of recent electronic equipments required higher operational voltage and higher capacity than ever, which is going to be driving force for developing new cathode materials. Some of them are $LiNi_{1-x}{M_xO_2}$, $Li[Ni_{x}Mn_{y}Co_{z}]O_{2}$, $Li[{Ni}_{1/2}{Mn}_{1/2}]O_{2}$. Other new type of cathode materials having high safety is also developed to apply for HEV (hybrid electrical vehicle) and power tool applications. ${LiMn}_{2}{O}_{4}$ and $LiFePO_4$ are famous for highly stable material, which are expected to give contribution to make safer battery. In near future, the various materials having both capacity and safety will be developed by new technology, such as solid solution composite.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.35-39
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• 2003

This paper is contents on the orthorhombic crystalline calcined by the solid phase method with LiMnO$_2$ thin film structured as the result which an average pore diameter of power was 132.3${\AA}$ in porosity analysis. Voltage ranges are able to get the properties of charge and discharge for experimental results of LiMnO$_2$ thin film were 2.2V 4.3V. The current density and scan speed were 0. 1㎃/$\textrm{cm}^2$ and 0.2㎷/sec respectively. Properties of the charge and discharge are obtained by optimum experiment condition parameters. Li dense ratio of the LiMnO$_2$ thin film that discharged capacities were 87㎃h/g have been 96.9［ppm］ at 670.784［nm］ wavelength. The dense ratio of Mn analyzed to 837［ppm］ at 257.610［nm］ wavelength. It can be estimated the quality of the LiMnO$_2$ thin film as that the wrong LiMnO$_2$ thin film pulled up from cell of electrolyte and became dry it at 800$^{\circ}C$. The results of SEM and XRD were the same as that of original researchers.

• Journal of the Korean Ceramic Society
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• v.38 no.5
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• pp.424-430
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• 2001

Cut-off 전압 변화에 따른 충방전 특성을 알아보기 위하여 Mn을 다른 전이 금속이 Co와 Ni로 소량 치환시킨 Li(M $n_{1-{\delta}}$ $n_{\delta}$)$_2$ $O_4$(M=Ni, Co, $\delta$=0, 0.05, 0.1, 0.2)를 고상 반응법으로 80$0^{\circ}C$에서 48시간 동안 유지하여 합성하였다. 충방전의 cut-off 전압은 2.5~4.4V, 3.0~4.5V, 3.5~4.5V, 3.5V~4.7V의 네 가지 전압범위고 하였다. 충방전 실험결과, Li(M $n_{1-{\delta}}$ $n_{\delta}$)$_2$ $O_4$의 용량은 각각 Co와 Ni의 $\delta$=0.1에서 최대를 보였다. Co 치환 조성 재료와 순물질 모두에서 최대의 용량을 보인 cut-off 전압대는 3.5~4.5V 이었는데 이때의 Li(M $n_{0.9}$ $Co_{0.1}$)$_2$ $O_4$와 LiM $n_2$ $O_4$의 초기 충전용량과 초기 방전용량은 각각 118, 119mAh/g과 114, 104mAh/g 이었다. 또한 모든 cut-off 전압대에서 Li(M $n_{0.9}$ $Co_{0.1}$)$_2$ $O_4$는 순수한 LiM $n_2$ $O_4$보다 더 높은 용량과 우수한 싸이클 성능을 보였으며 그 결과는 밀착형 전지구성에서도 일치하였다.하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.125-128
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• 2007

In these recent years, low cost and stable battery electrode materials have been studied for HV/HEV application. Spinel cathode material $LiMn_2O_4$ is widely studied as a promising cathode material of lithium ion secondary batteries because of it is low cost, easily to be prepared and capable to be operated in high voltage range. In this study, $LiMn_2O_4$ was undergoing surface modification with spinel lithium titanium oxide by sol-gel method in order to enhance its capacity retention. Properties of both unmodified and surface-modified $LiMn_2O_4$ were characterized by XRD, SEM, particle size analyzer while their cycling performance was tested with charge and discharge tester.