• Title/Summary/Keyword: Thin film batteries

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Electrochemical Behavior of TiO2 Nanotube/Ti Prepared by Anodizing for Micro-Lithium Ion Batteries

  • Park, Soo-Gil;Yang, Jeong-Jin;Rho, Jin-Woo;Kim, Hong-Il;Habazaki, Hiroki
    • Journal of the Korean Electrochemical Society
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    • v.17 no.1
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    • pp.13-17
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    • 2014
  • The $TiO_2$ nanotube/Ti electrode are used as an anode in thin-film lithium microbatteries is known to have high oxidation-reduction potential of 1.8 V (vs. $Li/Li^+$). It can prevent from dendrite growth of lithium during charging. The $TiO_2$ nanotube/Ti electrode was prepared by anodizing at constant voltages for thin-film lithium microbatteries. The capacities of $TiO_2$ nanotube/Ti anode prepared by anodizing at 10 V, 20 V and 30 V were observed to be $23.9{\mu}Ah\;cm^{-2}$, $43.1{\mu}Ah\;cm^{-2}$ and $74.0{\mu}Ah\;cm^{-2}$. We identified it was found that the capacity of $TiO_2$ nanotube/Ti increases with increasing anodizing voltage and the anatase structure of $TiO_2$ nanotube/Ti compared with amorphous structure has batter cycle performance than amorphous $TiO_2$ nanotube/Ti.

Layered Nickel-Based Oxides on Partially Oxidized Metallic Copper Foils for Lithium Ion Batteries

  • Chung, Young-Hoon;Park, Sun-Ha;Kim, Hyun-Sik;Sung, Yung-Eun
    • Journal of Electrochemical Science and Technology
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    • v.2 no.4
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    • pp.204-210
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    • 2011
  • Thin film electrodes have been intensively studied for active materials and current collectors to enhance the electrochemical performance. Here, porous structures of nickel-based oxide films, consisting of nickel oxide and copper (II) oxide, which was derived from the copper substrate during the annealing process, were deposited on metallic copper foils. The half-cell tests revealed excellent capacity retention after $80^{th}$ charge/discharge cycles. Some films showed an excess of the theoretical capacity of nickel oxides, which mainly originate from partially oxidized copper substrates during annealing. These results exhibit that both a preparation method of an active materials and partially oxidized current collectors could be important roles to apply thin film electrodes.

Electrochemical Characteristics of $V_2O_5$ based All Solid State Thin Film Microbattery by Ex-situ Sputtering Method (Ex-situ 스퍼터링법에 의한 $V_2O_5$ 전 고상 박막전지의 전기화학적 특성)

  • Lim Y.C.;Nam S.C.;Jeon E.J.;Yoon Y.S.;Cho W.I.;Cho B.W.;Chun H.S.;Yun K.S.
    • Journal of the Korean Electrochemical Society
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    • v.3 no.1
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    • pp.44-48
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    • 2000
  • Amorphous $V_2O_5$ cathode thin films were prepared by DC-magnetron sputtering at room temperature and the thin film rechargeable lithium batteries were fabricated with the configuration of $V_2O_5/LIPON/Li$ using sequential ex-situ thin film deposition techniques. The electrochemical characteristics of $V_2O_5$ cathode materials Prepared at 80/20 of $Ar/O_2$ ratio showed high capacity and cycling behaviors by half cell test. LIPON solid electrolytes films were prepared by RF-magnetron sputtering using the self-made $Li_3PO_4$ target in pure $N_2$ atmosphere, and it was very stable for lithium contact in the range of 1.2-4.0 V vs. Li. Metallic lithium were deposited on LIPON electrolyte by thermal evaporation methode in dry room. Vanadium oxide based full cell system showed the initial discharge capacity of $150{\mu}A/cm^2{\mu}m$ in the range of $1.2\~3.5V$.

Electrochemical properties and Estimation of $LiMnO_{2}$ Active Material Synthesis for Secondary Batteries (2차 전지용 $LiMnO_{2}$ 활물질 합성의 전기화학적 특성과 평가)

  • Wee, Sung-Dong;Gu, Hal-Bon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.210-215
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    • 2002
  • This thesis is contents on the crystal grown by the solide phase method at $925^{\circ}C$ with orthorhombic structure that $LiMnO_{2}$ active material synthesised with precurse $Mn_{2}O_{3}$ and $LiOH.H_{2}O$ material to get three voltage level. The porosity analysis of the grown crystal in secondary batteries $LiMnO_{2}$ thin film is $1.323E+02\AA$ of the average pore diameter of powder particles and its structure to be taken the pore diameter was prepared. Adding voltage area to get properties of charge and discharge of which experiment result of $LiMnO_{2}$ thin film area 2.2V~4.3V, current and scan speed were 0.1mAh/g and $0.2mV/cm^{2}$ respectively, and properties of the charge and discharge to be got optimum experiment condition parameter and density rate of Li for analyze that unit discharge capacity with metal properties is 87mAh/g was 96.9[ppm] at 670.784[nm] wavelength, and density rate of Mn analyzed 837[ppm] at 257.610[nm]. It can be estimated the quality of thin film that wrong cell reject from the bottle of electrolyte. The results of SEM and XRD were the same that of original researchers.

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Synthesis and characterization of LiCoO2 thin film by sol-gel process (Sol-gel법에 의한 LiCoO2 박막의 합성과 특성평가)

  • Roh, Tae-Ho;Yon, Seog-Joo;Ko, Tae-Seog
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.24 no.3
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    • pp.94-98
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    • 2014
  • $LiCoO_2$ thin film has received diverse attention as cathodes material of thin-film micro-batteries. In this study, $LiCoO_2$ thin films were synthesized on Au substrates by sol-gel spin coating method and an annealing process. Their structures were studied using X-ray diffraction and Raman Spectroscopy. The particle morphologies of these thin films were observed by Scaning electron microscope. From the results of X-ray diffractometry and Raman Spectroscopy analyses, it was found that as-grown films had the structure of spinel (LT-$LiCoO_2$) and layered-Rock-salt (HT-$LiCoO_2$) at $550^{\circ}C$ and $750^{\circ}C$ respectively. The annealed films at $650^{\circ}C$ were presumed to be the mixed state of these two types. Throlugh the scanning electron microscope, It was estimated that the particle size in as-grown films at $750^{\circ}C$, were larger crystilline particle than in those at the other lower temperature and well distributed in the film.

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

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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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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Fabrication and Electrochemical Characterization of All Solid-State Thin Film Micro-Battery by in-situ Sputtering (In-situ 스퍼터링을 이용한 잔고상 박막 전지의 제작 및 전기화학적 특성 평가)

  • Jeon Eun Jeong;Yoon Young Soo;Nam Sang Cheol;Cho Won Il;Shin Young Wha
    • Journal of the Korean Electrochemical Society
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    • v.3 no.2
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    • pp.115-120
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    • 2000
  • All solid-state thin film micro-batteries consisting of lithium metal anode, an amorphous LiPON electrolyte and cathode of vanadium oxide have been fabricated and characterized, which were fabricated with cell structure of $Li/LiPON/V_2O_5Pt$. The effect of various oxygen partial pressure on the electrochemical properties of vanadium oxide thin films formed by d.c. reactive sputtering deposition were investigated. The vanadium oxide thin film with deposition condition of $20\%\;O_2/Ar$ ratio showed good cycling behavior. In in-siか process, the LiPON electrolyte was deposited on the $V_2O_5$ films without breaking vacuum by r.f. magnetron sputtering at room temperature. After deposition of the amorphous LiPON, the Li metal films were grown by a thermal evaporator in a dry room. The charge-discharge cycle measurements as a function of current density and voltage variation revealed that the $Li/LiPON/V_2O_5$ thin film had excellent rechargeable properly when current density was $7{\mu}A/cm^2$. and cut-off voltage was between 3.6 and 2.7V In practical experiment, a stopwatch ran on this $Li/LiPON/V_2O_5$ thin film micro-battery. This result means that thin film micro-battery fabricated by in-siか process is a promising for power source for electronic devices.

The development of conductive 10B thin film for neutron monitoring (중성자 모니터링을 위한 전도성 10B 박막 개발)

  • Lim, Chang Hwy;Kim, Jongyul;Lee, Suhyun;Jung, Yongju;Choi, Young-Hyun;Baek, Cheol-Ha;Moon, Myung-Kook
    • Journal of Radiation Protection and Research
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    • v.39 no.4
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    • pp.199-205
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    • 2014
  • In the field of neutron detections, $^3He$ gas, the so-called "the gold standard," is the most widely used material for neutron detections because of its high efficiency in neutron capturing. However, from variable causes since early 2009, $^3He$ is being depleted, which has maintained an upward pressure on its cost. For this reason, the demands for $^3He$ replacements are rising sharply. Research into neutron converting materials, which has not been used well due to a neutron detection efficiency lower than the efficiency of $^3He$, although it can be chosen for use in a neutron detector, has been highlighted again. $^{10}B$, which is one of the $^3He$ replacements, such as $BF_3$, $^6Li$, $^{10}B$, $Gd_2O_2S$, is being researched by various detector development groups owing to a number of advantages such as easy gamma-ray discrimination, non-toxicity, low cost, etc. One of the possible techniques for the detection is an indirect neutron detection method measuring secondary radiation generated by interactions between neutrons and $^{10}B$. Because of the mean free path of alpha particle from interactions that are very short in a solid material, the thickness of $^{10}B$ should be thin. Therefore, to increase the neutron detection efficiency, it is important to make a $^{10}B$ thin film. In this study, we fabricated a $^{10}B$ thin film that is about 60 um in thickness for neutron detection using well-known technology for the manufacturing of a thin electrode for use in lithium ion batteries. In addition, by performing simple physical tests on the conductivity, dispersion, adhesion, and flexibility, we confirmed that the physical characteristics of the fabricated $^{10}B$ thin film are good. Using the fabricated $^{10}B$ thin film, we made a proportional counter for neutron monitoring and measured the neutron pulse height spectrum at a neutron facility at KAERI. Furthermore, we calculated using the Monte Carlo simulation the change of neutron detection efficiency according to the number of thin film layers. In conclusion, we suggest a fabrication method of a $^{10}B$ thin film using the technology used in making a thin electrode of lithium ion batteries and made the $^{10}B$ thin film for neutron detection using suggested method.

Preparation of Electrolytic Tungsten Oxide Thin Films as the Anode in Rechargeable Lithium Battery (리튬 이차전지용 텅스텐 산화물 전해 도금 박막 제조)

  • Lee, Jun-Woo;Choi, Woo-Sung;Shin, Heon-Cheol
    • Korean Journal of Materials Research
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    • v.23 no.12
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    • pp.680-686
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    • 2013
  • Tungsten oxide films were prepared by an electrochemical deposition method for use as the anode in rechargeable lithium batteries. Continuous potentiostatic deposition of the film led to numerous cracks of the deposits while pulsed deposition significantly suppressed crack generation and film delamination. In particular, a crack-free dense tungsten oxide film with a thickness of ca. 210 nm was successfully created by pulsed deposition. The thickness of tungsten oxide was linearly proportional to deposition time. Compositional and structural analyses revealed that the as-prepared deposit was amorphous tungsten oxide and the heat treatment transformed it into crystalline triclinic tungsten oxide. Both the as-prepared and heat-treated samples reacted reversibly with lithium as the anode for rechargeable lithium batteries. Typical peaks for the conversion processes of tungsten oxides were observed in cyclic voltammograms, and the reversibility of the heat-treated sample exceeded that of the as-prepared one. Consistently, the cycling stability of the heat-treated sample proved to be much better than that of the as-prepared one in a galvanostatic charge/discharge experiment. These results demonstrate the feasibility of using electrolytic tungsten oxide films as the anode in rechargeable lithium batteries. However, further works are still needed to make a dense film with higher thickness and improved cycling stability for its practical use.

Effects of deposition temperature on the properties of SnO2:Eu3+ thin films grown by radio-frequency magnetron sputtering (증착 온도가 라디오파 마그네트론 스퍼터링으로 성장한 SnO2:Eu3+ 박막의 특성에 미치는 영향)

  • Shinho Cho
    • Journal of the Korean institute of surface engineering
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    • v.56 no.3
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    • pp.201-207
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    • 2023
  • Eu3+-doped SnO2 (SnO2:Eu3+) phosphor thin films were grown on quartz substrates by radio-frequency magnetron sputtering. The deposition temperature was varied from 100 to 400 ℃. The X-ray diffraction patterns showed that all the thin films had two mixed phases of SnO2 and Eu2Sn2O7. The 880 nmthick SnO2:Eu3+ thin film grown at 100 ℃ exhibited numerous pebble-shaped particles. The excitation spectra of SnO2:Eu3+ thin films consisted of a strong and broad peak at 312 nm in the vicinity from 250 to 350 nm owing to the O2--Eu3+ charge transfer band, irrespective of deposition temperature. Upon 312 nm excitation, the SnO2:Eu3+ thin films showed a main emission peak at 592 nm arising from the 5D07F1 transition and a weak 615 nm red band originating from the 5D07F2 transition of Eu3+. As the deposition temperature increased, the emission intensities of two bands increased rapidly, approached a maximum at 100 ℃, and then decreased slowly at 400 ℃. The thin film deposited at 200 ℃ exhibited a band gap energy of 3.81 eV and an average transmittance of 73.7% in the wavelength range of 500-1100 nm. These results indicate that the luminescent intensity of SnO2:Eu3+ thin films can be controlled by changing the deposition temperature.