• 제목/요약/키워드: Si film anode

검색결과 41건 처리시간 0.022초

알루미늄 실리콘 나노분말을 이용한 리튬이온전지 음극재료에 관한 연구 (The Research on Aluminum and Silcon Nanoparticles as Anode Materials for Lithium Ion Batteries)

  • 김형조;;김형진;박원조
    • 동력기계공학회지
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    • 제17권1호
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    • pp.110-115
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    • 2013
  • The electrochemical performance and microstructure of Al-Si, Al-Si/C was investigated as anode for lithium ion battery. The Al-Si nano composite with 5 : 1 at% ratio was prepared by arc-discharge nano powder process. However, some of problem is occurred, when Al nano composite was synthesized by this manufacturing. The oxidation film is generated around Al-Si particles for passivating processing in the manufacture. The oxidation film interrupts electrical chemistry reaction during lithium ion insertion/extraction for charge and discharge. Because of the existence the oxidation film, Al-Si first cycle capacity is very lower than other examples. Therefore, carbon synthsized by glucose ($C_6H_{12}O_6$) was conducted to remove the oxidation film covered on the composite. The results showed that the first discharge cycle capacity of Al-Si/C is improved to 113mAh/g comparing with Al-Si (18.6mAh/g). Furthermore, XRD data and TEM images indicate that $Al_4C_3$ crystalline exist in Al-Si/C composite. In addition the Si-Al anode material, in which silicon is more contained was tested by same method as above, it was investigated to check the anode capacity and morphology properties in accordance with changing content of silicon, Si-Al anode has much higher initial discharge capacity(about 500mAh/g) than anode materials based on Aluminum as well as the morphology properties is also very different with the anode based Aluminum.

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • 황창묵;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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Studies of Lithium Diffusivity of Silicon-Based Film Electrodes for Rechargeable Lithium Batteries

  • Nguyen, Cao Cuong;Song, Seung-Wan
    • Journal of Electrochemical Science and Technology
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    • 제4권3호
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    • pp.108-112
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    • 2013
  • Lithium diffusivity of the silicon (Si)-based materials of Si-Cu and $SiO_x$ (x = 0.4, 0.85) with improved interfacial stability to electrolyte have been determined, using variable rate cyclic voltammetry with film model electrodes. Lithium diffusivity is found to depend on the intrinsic properties of anode material and electrolyte; the fraction of oxygen for $SiO_x$ (x = 0.4, 0.85), which is directly related to electrical conductivity, and the electrolyte type with different ionic conductivity and viscosity, carbonate-based liquid electrolyte or ionic liquid-based electrolyte, affect the lithium diffusivity.

Top Emitting Organic Light Emitting Diode with a Cr Anode on Flexible Substrate

  • Chung, Sung-Mook;Hwang, Chi-Sun;Lee, Jeong-Ik;KoPark, Sang-hee;Yang, Yong-Suk;Do, Lee-Mi;Chu, Hye-Yong
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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    • pp.1374-1377
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    • 2005
  • Top-emitting organic light-emitting diode (TEOLED) was fabricated on flexible substrate of PES film. Aluminum and Chromium multilayer was used as an anode of TEOLED and the TEOLEDs of Cr(20nm)/Al(100nm)/Cr(20nm)/NPB(60nm)/Alq(60nm)/LiF(1nm)/Al(2nm)/Ag(20nm)/NPB(200nm) has been fabricated on PES film and Si wafer for control device. The TEOLED on PES film which had good anode surface morphology, showed very similar device characteristics to that on Si wafer.

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리튬 이차전지에서 Si 음극박막의 스퍼터링 증착조건에 따르는 구조적, 전기화학적 특성 연구 (Influence of Sputtering Conditions on Structural and Electrochemical Properties of the Si Anode Film for Lithium Secondary Batteries)

  • 주승현;이성래;조병원;조원일
    • 한국재료학회지
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    • 제19권2호
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    • pp.73-78
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    • 2009
  • This study investigated the dependence of the various sputtering conditions (Ar pressure: $2{\sim}10\;mTorr$, Power: $50{\sim}150\;W$) and thickness ($50{\sim}1200\;nm$) of Si thin film on the electrochemical properties, microstructural properties and the capacity fading of a Si thin film anode. A Si layer and a Ti buffer layer were deposited on Copper foil by RF-magnetron sputtering. At 10 mTorr, the 50 W sample showed the best capacity of 3323 mAh/g, while the 100 W sample showed the best capacity retention of 91.7%, also at 10 mTorr. The initial capacities and capacity retention in the samples apart from the 50W sample at 10 mTorr were enhanced as the Ar pressure and power increased. This was considered to be related to the change of the microstructure and the surface morphology by various sputtering conditions. In addition, thinner Si film anodes showed better cycling performance. This phenomenon is caused by the structural stress and peeling off of the Si layer by the high volume change of Si during the charge/discharge process.

Li0.5La0.5TiO3와 Si박막을 갖는 구리 집전체의 Li free 음극으로써의 전기화학적 특성 (Electrochemical Properties of Cu Current Collector with Li0.5La0.5TiO3 or Si Thin Film as a Li Free Anode)

  • 이재준;김수호;이종민;윤영수
    • 전기화학회지
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    • 제9권1호
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    • pp.34-39
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    • 2006
  • Li free 음극으로써 구리 foil 집전체에 $Li_{0.5}La_{0.5}TiO_3$ 및 Si 박막을 r.f, 스퍼터링법을 이용하여 증착하고 양극 물질로는 $Li[Co_{0.1}Ni_{0.15}Li_{0.2}Mn_{0.55}]O_2$를 이용하여 전기화학적 특성을 평가하였다. 박막 증착시 플라즈마 내(in-plasma)와 밖(out of plasma)에 구리 foil을 각각 위치시켰다. X-ray 회절 분석의 경우 각각의 조건에서 $Li_{0.5}La_{0.5}TiO_3$ 및 Si 모두 결정 특성의 차이를 발견할 수 없었다. $Li_{0.5}La_{0.5}TiO_3$의 경우 플라즈마 내에서 증착된 경우 그리고 Si 경우는 플라즈마 밖에서 증착된 경우 각각 싸이클 특성이 우수한 것으로 나타났다. 이는 $Li_{0.5}La_{0.5}TiO_3$ 경우 결정성이 존재할 경우 이온전도 특성이 우수하며 Si 경우 플라즈마 내에서 성장된 박막이 더욱 치밀하여 충방전 중 부피변화에 더욱 민감하였기 때문으로 판단된다. 이상의 결과로부터 (1)전지 용량을 갖는 5게 의한 표면 개질의 경우 구조적으로 안정할 수 있는 비정질 상의 Si이 보다 더 바람직하며 (2) 이온전도 특성을 보이는 $Li_{0.5}La_{0.5}TiO_3$와 같은 소재를 이용하여 표면 개질을 할 경우 Li의 확산이 더욱 용이한 구조가 바람직할 것으로 판단된다.

Active-Matrix Field Emission Display with Amorphous Silicon Thin-Film Transistors and Mo-Tip Field Emitter Arrays

  • Song, Yoon-Ho;Hwang, Chi-Sun;Cho, Young-Rae;Kim, Bong-Chul;Ahn, Seong-Deok;Chung, Choong-Heui;Kim, Do-Hyung;Uhm, Hyun-Seok;Lee, Jin-Ho;Cho, Kyoung-Ik
    • ETRI Journal
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    • 제24권4호
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    • pp.290-298
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    • 2002
  • We present, for the first time, a prototype active-matrix field emission display (AMFED) in which an amorphous silicon thin-film transistor (a-Si TFT) and a molybdenum-tip field emitter array (Mo-tip FEA) were monolithically integrated on a glass substrate for a novel active-matrix cathode (AMC) plate. The fabricated AMFED showed good display images with a low-voltage scan and data signals irrespective of a high voltage for field emissions. We introduced a light shield layer of metal into our AMC to reduce the photo leakage and back channel currents of the a-Si TFT. We designed the light shield to act as a focusing grid to focus emitted electron beams from the AMC onto the corresponding anode pixel. The thin film depositions in the a-Si TFTs were performed at a high temperature of above 360°C to guarantee the vacuum packaging of the AMC and anode plates. We also developed a novel wet etching process for $n^+-doped$ a-Si etching with high etch selectivity to intrinsic a-Si and used it in the fabrication of an inverted stagger TFT with a very thin active layer. The developed a-Si TFTs performed well enough to be used as control devices for AMCs. The gate bias of the a-Si TFTs well controlled the field emission currents of the AMC plates. The AMFED with these AMC plates showed low-voltage matrix addressing, good stability and reliability of field emission, and good light emissions from the anode plate with phosphors.

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Carbon Film 전기적 특성 (Characteristics of Carbon Thin Film Using Electrochemical Method)

  • 이상헌;최용
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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    • pp.126-127
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    • 2007
  • In this study, the fabrication technique of a plannar field emission structure with DLC were studied Electric properties of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The DLC film deposited on the Si substrate, plannar $SiO_2$ was obtained due to the shape of bottom electrode.

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Thermal Stability of Lithiated Silicon Anodes with Electrolyte

  • Park, Yoon-Soo;Lee, Sung-Man
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.145-148
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    • 2011
  • The thermal behavior of lithiated Si anodes has been investigated using differential scanning calorimetry (DSC). In particular, the effect of Si particle size on the thermal stability of a fully lithiated Si electrode was investigated. For DSC measurements, a lithiated Si anode was heated in a hermetically sealed high-pressure pan with a polyvinylidene fluoride (PVDF) binder and a 1 M $LiPF_6$ solution in an ethylene carbonate (EC)-diethyl carbonate (DEC) mixture. The thermal evolution around $140^{\circ}C$ increases with lithiation and with decreasing particle size; this phenomenon is attributed to the thermal decomposition of the solid electrolyte interface (SEI) film. Exothermic peaks, following a broad peak at around $140^{\circ}C$, shift to a lower temperature with a decrease in particle size, indicating that the thermal stability of the lithiated Si electrode strongly depends on the Si particle size.