전고상박막전지를 위한 (Li,La)TiO₃ 고체전해질의 제조와 특성

안준구,윤순길 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.9

$({Li}_{0.5}0{La}_{0.5}){TiO}_3$ (LLTO) solid electrolyte was grown on LiCo{O}_2 (LCO) cathode films deposited on $Pt/Ti{O}-2/Si{O}_2/Si$ substrate using pulsed laser deposition for all-solid-state lithium microbattery. LLTO solid electrolyte exhibits an amorphous phase at various deposition temperatures. LLTO films deposited at 10$0^{\circ}C$ showed a clear interrace without any chemical reaction with LCO, and showed an initial discharge capacity of 50 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 90 % after 100 cycles with Li anode in 1mol$ LiCl{O}_4$ in propylene carbonate (PC). The increase of capacity retention in LLTO/LCO structure than LCO itself was attributed to the structural stability of LCO cathode films by the stacked LLTO. The cells of LLTO/LCO with LLTO grown at $100^{\circ}C$ showed a good cyclic property of 63.6 % after 300 cycles. An amorphous LLTO solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium microbattery.

Robust yarn electrodes for microbatteries with high areal capacity

Park, Sarang,Lee, Byoung-Sun,Kang, Tae-Hyung,Choi, In-Suk,Yu, Woong-Ryeol Elsevier 2019 Materials & Design Vol.166 No.-

<P><B>Abstract</B></P> <P>This work reports the design strategy of mechanically robust yarn electrodes having high areal capacity (ca. 14 mAh/cm<SUP>2</SUP>) as building blocks for microbatteries. Lithium iron phosphate (LiFePO<SUB>4</SUB>) was embedded into poly(acrylonitrile) nanofibers (NFs) via electrospinning. The obtained NFs were assembled into yarns via a yarning process, and were then thermally treated to produce carbon NF yarns. A hot-stretching process was used between the yarning and thermal treatment processes, improving the mechanical (tensile modulus of 1.03 GPa and strength of 38 MPa) and electrical (43.1 S/cm) properties of the yarn electrodes. The free-standing yarn electrodes with different mass loadings showed stable cycling performances with reasonable reversible capacity (ca. 112 mAh/g) up to 30 cycles. These mechanically robust and electrochemically excellent yarn electrodes could serve as building blocks for various structures in advanced microbatteries requiring high areal density.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Twisted nanofiber yarn was designed as a building block electrode for microbatteries. </LI> <LI> Yarn electrodes revealed excellent mechanical (tensile strength of 38 MPa) and electrical (43.1 S/cm) properties. </LI> <LI> Free-standing yarn electrodes showed high areal capacity (ca. 14 mAh/cm2) and cycling stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

전기뱀장어의 전기발생을 모사한 고전압 액체 전해질 미소전지

김문철(Mun Chul Kim),조영호(Young-Ho Cho) 대한기계학회 2009 大韓機械學會論文集A Vol.33 No.5

We present high-voltage liquid-electrolyte microbatteries, inspired from the high-voltage generation mechanism of electric eels using serially connected multiple-cell arrays. In the microbatteries, we purge air into the electrolyte filled in a channel layer to isolate serially connected multiple cell arrays using three surface-tension valves (cell-front, outlet, and cell-end valves). Compared to the previous multi-cell stack or interconnection, present microbatteries provide a reduced multi-cell charging time. We have designed and characterized four different prototypes C1, C10, C20, and C40 having 1, 10, 20, and 40 cells, respectively. In the experimental study, the threshold pressures of cell-front, outlet, and cell-end valves were measured as 460±47, 1,000±53, and 2,800±170 Pa, respectively. The average charging time for C40 was measured as 26.8±4.9 seconds where the electrolyte and air flow-rates are 100 and 10 ㎕/min, respectively. Microbatteries showed the maximum voltage of 12 V (C40), the maximum power density of 110 ㎼/㎠ (C40), and the maximum power capacity of 2.1 μAh/㎠ (C40). We also proposed a tapered-channel to remove the reaction gas from the cell chamber using a surface tension effect. The present microbatteries are applicable to high-voltage portable power devices.

리튬 미소전지용 $LiCoO_2$ 박막양극의 전기화학적 특성에 미치는 기판의 영향

이종기,이승주,백홍구,이성만,Lee Jong-Ki,Lee Seung-Joo,Baik Hong-Koo,Lee Sung-Man 한국전기화학회 2000 한국전기화학회지 Vol.3 No.3

기판의 변화가 박막전극의 전기화학적 특성에 미치는 영향을 조사하기 위해 박막 $LiCoO_2$ 양극을 alumina, chemically etched-Si그리고 flat-Si기판 위에 증착하였다. Alumina기판의 경우 산소 분위기, $800^{\circ}C$ 30분간 열처리 후 내부에 균열이 존재하는 매우 큰 결정이 형성되었으나 flat-Si 기판의 경우에는 미세하며 균일한 결정이 관찰되었다. Flat-Si 기판 위에 증착된 박막은 alumina또는 식각된 Si 기판의 경우에 비하여 peak potential증감 및 고 전류밀도 방출 능면에서 매우 우수한 특성을 나타내었으며 이는 열처리 후 형성된 결정립의 크기, 표면 형상 및 전류 집전체의 전기저항 차이에 기인한 것으로 생각되었다. In order to investigate the substrate effect on the electrochemical properties of thin-film electrode, $LiCoO_2$ was deposited onto the alumina, chemically etched-Si and flat-Si substrates. After annealing at $800^{\circ}C$ in $O_2$ for 30min, the film deposited on the alumina consisted of large particles with several cracks, whereas the film deposited on the flat-Si substrate was composed of very small and uniform particles. The films deposited on the flat-Si showed improved electrochemical properties such as peak potential divergence and rate-capability, over those deposited on the alumina and chemically etched-Si substrate, which can be attributed to the differences of the particle size surface morphology, and the electrical resistance of the current collector.

산소량에 따른 $SnO_x$ 박막의 음극 특성

문희수,성상현,김영일,박종완,Moon Hee-Soo,Seong Sang-Hyun,Kim Young-Il,Park Jong-Wan 한국전기화학회 2000 한국전기화학회지 Vol.3 No.3

본 실험에서는 리튬 이차 박막전지의 음극물질로 주석 산화물 박막을 RF magnetron sputter을 이용하여 증착하였다. RF power와 공정 압력을 각각 $2.5W/cm^2$와 10mTorr로 고정시키고 박막 중의 산소량을 조절하기 위해 산소 분압을 $0\~100\%$까지 조절하여 실험하였으며, 산소량을 더 줄이기 위해 주석 금속 칩을 사용하여 조절하였다. 산소량을 줄여 줌으로써 비가역적으로 형성되는 리튬산화물의 량을 줄이고 고용량의 $SnO_x$음극 박막을 제조하였다. 그 중 $SnO_{1.43}$일 때 가장 큰 가역용량(약$ 500{\mu}Ah/cm^2{\mu}m$) 얻었다. In this experiments, tin oxide thin film anode for microbattery was deposited by using RF magnetron sputtering. The RF power and operating pressure during deposition were fixed at $2.5W/cm^2$ and 10mTorr respectively. The partial pressure of oxygen was varied from $0\%\;to\;100\%$ to control oxygen content and metal Sn chips were used further reducing of oxygen content. According to reduction in the oxygen content formation of the irreversible $Li_2O$ was reduced a thin film anode of $SnO_x$ of high capacity was fabricated. The optimum $SnO_x$, thin film was $SnO_{1.43}$ which exhibited a reversible capacity of $ 500{\mu}Ah/cm^2{\mu}m$ and exhibited good reversibility.

R.F. 마그네트론 스퍼터링을 이용한 LiCoO2 양극활물질의 Ar 증착분압에 따른 박막전지 전극 특성

박호영,임영창,최규길,이기창,박기백,권미연,조성백,남상철 한국전기화학회 2005 한국전기화학회지 Vol.8 No.1

Ar 공정 분압에 따라 스퍼터링된 LiCoO2 박막 양극의 400℃ 저온 열처리를 통한 전기화학적 및 미세구조적 특성을 연구하였다. Ar 분압이 변화함에 따라 양극 박막의 미세구조 및 조성이 변화하였으며, Ar 분압이 증가할수록 LiCoO2 박막의 안정성 및 전기화학적 특성이 개선되었다. 순환전류전위법 및 정전류 충방전 시험에 의해 전극반응의 가역성 및 안정성 등을 고찰하였으며, 박막의 조성, 결정성, 표면 특성 등 물리적 특성은 ICP-AES, XRD, SEM 및 AFM을 통해 분석하였다.

Fabrication of Lithium Nickel Cobaltate Thin-film for the Cathode Material of Microbattery

Kim, Duksu,Kim, Mun-Kyu,Son, Jong-Tae,Kim, Ho-Gi The Korean Ceramic Society 2001 한국세라믹학회지 Vol.38 No.8

Electrochemically active lithium nickel cobalt oxide thin-film was not fabricated until now. The thin-film was deposited by RF magnetron sputtering at room temperature, and its initial phase was amorphous. By varying deposition condition, the different characteristics of thin-film were achieved. Using electrochemical analyses, the relationship between physical and electrochemical characteristics was identified. Crystallized thin-film by RTA (Rapid Thermal Annealing) was shown a good capacity and cycle property.

급속 열처리된 LiNi_(1-x)Co_xO_2 양극 박막을 이용한 전고상 박막형 마이크로 전지의 제작 및 특성 평가

金漢基,成泰連,尹榮秀 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.5

We report on fabrication of all solid-state thin film microbattery(TFB) that has a structure of Li/LiPON/ LiNi_(1-x)Co_xO_2/Pt/MgO/Si multilayer. The LiNi_(1-x)Co_xO_2 films were grown by radio-frequency(rf) magnetron reactive sputtering system using synthesized LiNi_(1-x)Co_xO_2 target in a 9:1 Ar/O_2 mixture gas. X-ray diffraction(XRD), transmission electron microscopy(TEM), and selective area diffraction(SAD) analysis show that rapid thermal annealed LiNi_(1-x)Co_xO_2 film has (101) and (104) preferred orientation with increasing film thickness. In addition, scanning electron microscopy(SEM), atomic force microscope(AFM), and Auger electron spectroscopy(AES) examination exhibit that the surface layer on as-deposited LiNi_(1-x)Co_xO_2 film was completely removed by rapid thermal annealing process. All solid state TFB, fabricated by using the annealed LiNi_(1-x)Co_xO_2 cathode film, shows stable cyclibility and high specific discharge capacity of 60.2 ㎂h/㎠-㎛. It was thought that the combined feature of a LiCoO_2 and a LiNiO_2 cathode caused fairly high capacity and stable cyclibility of the LiNi_(1-x)Co_xO_2 based TFB.

Fabrication of high-power lithium micro-batteries by modification with 2-dimensional nanosheets

Haena Yim,Hyun Seok Lee,Ji-Won Choi 한국진공학회 2019 한국진공학회 학술발표회초록집 Vol.2019 No.2

Fabrication of 3-Dimensional LiMn2O4 Thin Film

Bo Gun Park,Jea Hyeok Ryu,Won Youl Choi,Yong Joon Park 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.3

3-Dimensionally ordered macroporous LiMn2O4 thin film was prepared by a sol-gel and dip coating method on Pt/Ti/SiO2/Si substrate. An opal structure consisting of mono dispersed polystyrene beads (300 nm) was used as a template. After solution containing Mn and Li precursors was coated on the template-deposited substrate, the template and organic materials in the precursors was removed by calcination at 400 °C . And then the 3-dimensional LiMn2O4 thin film with spinel structure was fabricated by heat treatment at 700 °C . The structural and electrochemical property was investigated by XRD, SEM and charge-discharge cycler.