• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.713-716
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• 2001

In many papers, the electrochemical analysis of LiMn$_2$O$_4$shows the transition results of Mn$^{3+}$ ion. Charge ordering is accompanied by simultaneous orbital ordering due to the Jahn-Teller effect in Mnl$^{3+}$ ions. To analyze the cycle performance of LiMn$_{2-x}$Cu$_{x}$ O$_4$as the cathode of 4 V class lithium secondary batteries, XRD, TGA analysis were conducted. Although the cycle performance of the LiMn$_{2-x}$Cu$_{x}$ O$_4$was improved from pure LiMn$_2$O$_4$, the discharge capacity was significantly lower than LiCoO$_2$. In this paper, We study the Electrochemical characterization and enhanced stability of Cu-doped spinels in the LiMn$_{2-x}$Cu$_{x}$ O$_4$upon initial cycling.l cycling.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.287-287
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• 2010

휴대용 기기의 사용이 증가하면서 배터리의 고용량화와 소형화가 요구되고 있다. 특히 내시경 캡슐과 같은 의료용 센서 기기에서는 소형화가 매우 중요하며 인체에 해로운 액체전해질이 들어가지 않는 것이 바람직하다. 최근 무선센서, RFID 태그, 스마트 카드 등을 위하여 고체전해질을 사용하는 박막 마이크로 배터리가 개발되고 있으나, 에너지 저장용량이 작아 응용분야가 제한적이다. Si wafer 위에 형성된 고단차의 3차원 구조 위에 박막 배터리를 형성한다면 표면적 증가에 의해 에너지 저장용량 역시 크게 증가할 것이며, Si 기반의 반도체, 디스플레이, 태양전지 등과 쉽게 집적이 가능할 것이다. 본 연구에서는 펄스 레이저 증착법(Pulsed Laser Deposition)으로 리튬 배터리의 cathode 물질인 $LiCoO_2$를 박막으로 제조하고 그 특성을 연구하였다. 펄스 레이저 증착법은 저온 증착이 가능하고 타겟 물질과 같은 조성의 박막을 증착하는 것이 용이한 장점이 있다. Pt, TiN 등의 기판 위에 $LiCoO_2$ 박막을 증착하고 증착 온도와 산소($O_2$) 분압이 박막의 조성, 미세구조, 결정성, 그리고 전하저장용량에 미치는 영향을 고찰하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.202-203
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• 2005

To recognize whether admixture affects some $(Ba_{0.6}Sr_{0.4})TiO_3$, powder in this research $Li_2CO_3$, MgO, $MnO_2$ adding each 3 wt % by Tape casting method thick film make. Sitering temperature lowered 1300$^{\circ}C$ adding $Li_2CO_3$, and density is 5.942g/$cm^3$, and specific inductive capacity increases about decuple and displayed 4000. Climbed sitering temperature 1400$^{\circ}C$ adding MgO, specific inductive capacity reduced 1/2 times. Lowered sintering temperature 1325$^{\circ}C$ low adding $MnO_2$.

• 한국세라믹학회지
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• 제38권9호
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• pp.777-781
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• 2001

$LiCoO_{2}$ thin films have received attention as cathodes of thin film microbatteries in these days. In this study, $LiCoO_{2}$ thin films are fabricated by a sol-gel spin coating method followed by a post-annealing process. The thermal decomposition behaviour of precursor is investigated by TG/DTA analysis. The change of crystallinity, microstructure and electrochemical properties of final films as the drying temperature changes are also studied by XRD, SEM and galvanostatic charge/discharge cycling test. The relationship between the discharge capacity and the drying temperature are intensively investigated in this work.

• Environmental Engineering Research
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• 제25권1호
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• pp.88-95
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• 2020

An investigation of rare metals recovery from LiNi_xCo_yMn_zO₂ cathode material of the end-of-life lithium-ion batteries is presented. To determine the influence of reductant on the leach process, the cathode material (containing Li 7.6%, Co 20.4%, Mn 19.4%, and Ni 19.3%) was leached in H₂SO₄ solutions either with or without H₂O₂. The optimal process parameters with respect to acid concentration, addition dosage of H₂O₂, temperature, and the leaching time were found to be 2.0 M H₂SO₄, 4 vol.% H₂O₂, 70℃, and 150 min, respectively. The yield of metal values in the leach liquor was > 99%. The leach liquor was subsequently treated by precipitation techniques to recover nickel as Ni(C₄H₇N₂O₂)₂ and lithium as Li₂CO₃ with stoichiometric ratios of 2:1 and 1.2:1 of dimethylglyoxime:Ni and Na₂CO₃:Li, respectively. Cobalt was recovered by solvent extraction following a 3-stage process using Na-Cyanex 272 at pH_eq ~5.0 with an organic-to-aqueous phase ratio (O/A) of 2/3. The loaded organic phase was stripped with 2.0 M H₂SO₄ at an O/A ratio of 8/1 to yield a solution of 114 g/L CoSO₄; finally recovered CoSO₄.xH₂O by crystallization. The process economics were analyzed and found to be viable with a margin of $476 per ton of the cathode material.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.511-516
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• 2004

A Li$[Co_{0.17}Li_{0.28}Mn_{0.55}]O_2$ cathode compound was prepared by a simple combustion method. The X-ray diffraction pattern showed that this compound could be classified as ${\alpha} -NaFeO_2$ structure type with the lattice constants of a = 2.8405(9) ${\AA}$ and c = 14.228(4) ${\AA}$. According to XANES analysis, the oxidation state of Mn and Co ions in the compound were 4+ and 3+, respectively. During the first charge process, the irreversible voltage plateau at around 4.65 V was observed. The similar voltage-plateau was observed in the initial charge profile of other solid solution series between $Li_2MnO_3\;and\;LiMnO_2$ (M=Ni, Cr...). The first discharge capacity was 187 mAh/g and the second discharge capacity increased to 204 mAh/g. As the increase of cycling number, one smooth discharge profile was converted to two distinct sub-plateaus and the discharge capacity was slowly decreased. From the Co and Mn K-edge XANES spectra measured at different cyclic process, it can be concluded that irreversible transformation of phase is occurred during continuous cycling process.

• 한국재료학회지
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• 제12권10호
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• pp.771-775
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• 2002

$Gd_2$$O_3$:Eu phosphor particles with nano-sized and non-aggregation characteristics were prepared by spray pyrolysis using the spray solution containing polymeric precursor and $Li_2$$CO_3$ flux material. Nano-sized $Gd_2$$O_3$:Eu phosphor particles had higher brightness than the commercial $Y_2$$O_3$:Eu phosphor particles. The $Gd_2$$O_3$:Eu phosphor particles had nano-size and non-aggregation characteristics after heat-treatment at $1000^{\circ}C$ when the addition amount of $Li_2$$CO_3$ flux was 1 wt.% and 3 wt.%. The mean size of particles were 200 nm and 400 nm when the amount of flux was 1 wt.% and 3 wt.%, respectively. The prepared phosphor particles had higher photoluminescence intensity than that of the commercial product regardless of the content of$ Li_2$$CO_3$ flux and had the maximum brightness when the content of flux was 5 wt %. The photoluminescence intensity of the nano-sized $Gd_2$$O_3$:Eu phosphor particles containing 3 wt.% $Li_2$$CO_3$ flux was 125% in comparison with that of the micron-sized $Y_2$$O_3$:Eu commercial product.

• 전기화학회지
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• 제20권4호
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• pp.67-74
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• 2017

층상구조의 Ni-rich NCM계 양극활물질 $Li[Ni_xCo_{(1-x)/2}Mn_{(1-x)/2}]O_2$ ($x{\geq}0.6$)은 $LiCoO_2$ 대비 높은 에너지밀도와 가격 경쟁력의 장점을 가진다. Ni 함량에 비례하여 가역 방전용량이 증가하는 장점이 있는 반면, 합성 중에 발생하는 양이온 혼합으로 인해 안정적인 전기화학성능을 구현하기 어려운 문제가 있다. 본 연구에서는 합성 분위기, 리튬 원료물질, 합성 시간, 합성 온도, Li/M (M=transition metal) 비율 등의 다양한 합성조건을 변수로 하여 Ni 함량 증가에 따라 최적의 층상구조 Ni-rich NCM을 각각 합성하고 이에 대한 전기화학성능을 보고하였다. $Li[Ni_{0.6}Co_{0.2}Mn_{0.2}]O_2$ (NCM6)을 기준으로 Ni 함량이 증가한 $Li[Ni_{0.7}Co_{0.15}Mn_{0.15}]O_2$ (NCM7)와 $Li[Ni_{0.8}Co_{0.1}Mn_{0.1}]O_2$ (NCM8)의 합성시 전이금속 중 Ni의 비율이 증가함에 따라 양이온 혼합이 증가하는 것이 관찰되었고, 이는 전기화학 성능에 부정적인 영향을 끼치는 것으로 확인되었다. Ni 비율별 NCM에 대한 연구결과 비율 내확인한 최적의 조건에서 NCM6은 $180mAh{\cdot}g^{-1}$, 96.2% (50회), NCM7은 $187mAh{\cdot}g^{-1}$, 94.7% (50회), NCM8은 $201mAh{\cdot}g^{-1}$, 92.7% (50회)의 초기 방전용량 및 수명평가 후 용량유지율 값을 각각 구현하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.64-65
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• 2008

3D microbattery에 사용할 수 있는 $LiMn_2O_4$ 3차원 박막전극을 제조하여 그 전기화학적 특성을 관찰하였다. 3차원 구조의 형성을 위하여 먼저 polystyrene(PS) microsphere를 platinum이 증착된 Si/$SiO_2$ 기판위에 dip-coating 방식으로 코팅시켜 template로 사용하였다. 그 위에 sol-gel법을 이용, 박막을 형성시킨 후 template 를 제거하는 방식으로 $LiMn_2O_4$ 3차원 박막전극을 형성하였는데 이때 solution은 Lithium acetylacetonate[$LiCH_3CO-CHCOCH_3$], Manganese(III) acetylacetonate [Mn$(CH_3COCHCOCH_3)_3$]를 source 물질로 1-butanol과 acetic acid를 solvent로 활용하여 제조하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.7-9
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• 2006

$(BaSr)TiO_3$ thick films were prepared by tape casting method using $BaTiO_3$ and $SrTiO_3$ powder slurry in order to investigate dielectric properties and low temperature sintering. Sintering density was $5.7\;g/cm^3$ and the BST sample exhibited the maximum dielectric constant, tunability at temperatures near phase transition point. The dielectric constant was increased and curie temperature was shifted to higher temperature with increasing of annealing temperature.