• Journal of the Korean Ceramic Society
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• v.33 no.4
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• pp.405-410
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• 1996

The partial substitution of LiTaO3 with Al2O3 caused the variation of dielectric properties and a lower melting temperature yielding an easier growth of single crystal. The lattice constants and Raman band broadening were measured for the LiTaO3 solid solution in which the cations of Li+ and Ta5+ were partially substituted by Al3+ cation. The LiTaO3 type limit phases were obtained. ; Li1.15Al0.45Ta0.7O3 for cationic excess Li1.15Al0.45Ta0.7O3 for stoichiometry Li0.85Al0.05TaO3 for cationic deficit. The second phase was formed beyond the solubility limit. The limit phase (Li0.85Al0.05TaO3) in the region of cationic deficit showed the lowest Cuire temperature of 61$0^{\circ}C$ and melting point of 152$0^{\circ}C$ compared to the solid solutions in other regions (TMp=1$650^{\circ}C$, Tc=69$0^{\circ}C$ for LiTaO3)

• Journal of the Korean Electrochemical Society
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• v.8 no.4
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• pp.172-176
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• 2005

Recently, many researches on the high-voltage 5 V class cathode material have focused on $LiNi_{0.5}Mn_{1.5}O_4$, where $Mn^{3+}$ in the existing $LiMn_2O_4 (Li[Mn^{3+}][Mn^{4+}]O_4)$ is replaced by $Ni^{2+}(Li[Ni^{2+}]_{0.5}[Mn^{4+}]_{1.5}O_4)$ in order to utilize $Ni^{2+}/Ni^{4+}$ redox reaction in the 5V region. The partial substitution of Mn in $LiMn_2O_4$ for other transition metal element, $LiM_yMn_{1-y}O_4$(M=Cr, Al, Ni, Fe, Co, Cu, Ga etc) is known as a good solution to overcome the problems associated with $LiMn_2O_4$ like the gradual capacity fading. In this study, we synthesized $LiNi_{0.5}Mn_{1.5}O_4$ through a mechanochemical process and investigated its morphological, crystallographic and electrochemical characteristics. The results showed that 4 V peaks had been found in the cyclic volammograms of the synthesized powders due to the existence of $Mn^{3+}$ from the incomplete substitution of $Ni^{2+}$ for $Mn^{3+}$ implying that the mechanochemical activation alone was not good enough to synthesize an exact stoichiometric compound of $LiNi_{0.5}Mn_{1.5}O_4$. The synthetic condition of mechanochemical process, such as type of starting materials, ball-mill and calcination condition was optimized for the best electrochemical performance.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.137.1-137.1
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• 2011

올리빈 구조의 $LiFePO_4$ 정극 활물질은 $650^{\circ}C$에서 고상법으로 제조되었다. $LiFePO_4$의 전자전도도를 향상시키기 위하여 graphite nanofiber(GNF)를 각각 3wt%, 5wt%, 7wt%, 9wt% 첨가하여 $LiFePO_4$-C를 제조하였다. 제조된 분말의 입자 형태를 확인하기 위하여 X-ray diffraction(XRD)과 File Electronic Scaning Electromicroscopy(FE-SEM)를 측정하였다. XRD결과로부터 제조된 분말은 모두 순수한 결정 구조를 나타내었고 입자의 크기는 약 200nm였다. 5wt% GNF를 첨가한 $LiFePO_4$-C는 기타 첨가량에 비해 방전용량이 가장 높았다. 첫 사이클의 용량은 151.73mAh/g 나타났고 50 사이클 뒤에도 92% 이상을 유지하고 있었다. 첨가하지 않은 것에 비해 43% 증가하였다. $LiFePO_4$-C(3wt%), $LiFePO_4$-C(7wt%), $LiFePO_4$-C(9wt%)의 첫 사이클 방전용량은 각각 147.94mAh/g, 136.64mAh/g, 121.07mAh/g 나타났다. $LiFePO_4$-C(5wt%)에 비해 용량은 떨어쪘지만 순수한 $LiFePO_4$보다 많이 높았다. 임피던스 결과를 보면 기타 첨가량에 비해 $LiFePO_4$-C(5wt%)의 저항 제일 낮았다. 이는 충방전 결과와 일치하였다. graphite nanofiber의 첨가로 인하여 $LiFePO_4$ 정극 활물질의 전자전도도가 높아지고, 따라서 전기화학적 특성도 크게 향상되었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.3
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• pp.120-123
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• 2005

The 5 mol% ZnO doped $LiNbO_3$ film and the 2 mol% MgO doped $LiNbO_3$ film were grown on the $LiNbO_3$ (001) substrate by liquid phase epitaxy (LPE) method with $Li_2CO_3-V_2O_5$ flux system. The crytsallinity and the lattice mismatch between $Zn:LiNbO_3$, film and $Mg:LiNbO_3$, film were analyzed by x-ray rocking curve (XRC). In addition, the ZnO and MgO distribution in the cross-section of the multilayer thin films was observed using electron probe micro analyzer (EPMA).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.27-30
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• 2002

ZnO co-doped Er:$LiNbO_3$ single crystal thin films have been grown on $LiNbO_3$ (001) substrate by liquid phase epitaxy (LPE) method. The melts of ZnO co-doped Er:$LiNbO_3$ was fixed $Er_2O_3$, concentration (1 mol%) and different ZnO concentrations 3 and 5 mol%. The crystallinity of ZnO co-doped Er :$LiNbO_3$ films became better than the $LiNbO_3$ substrate. At ZnO 5 mol% concentration, the surface of ZnO co-doped Er:$LiNbO_3$ film is affected by compressive stress along both the perpendicular and the parallel direction. Also the surface of ZnO 3 mol% co-doped Er:$LiNbO_3$film is smoother than the original $LiNbO_3$ substrate surface.

• Journal of the Korean Electrochemical Society
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• v.14 no.1
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• pp.16-21
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• 2011

$Li_4Sn_xTi_{5-x}O_{12}$ was manufactured by high energy ball milling (HEBM) and used as an anode material for lithium ion battery. Various amount of $SnO_2$was added to $Li_4Ti_5O_{12}$ and heated at different temperatures. The purpose of this research was to see the effect of $SnO_2$ addition into $Li_4Ti_5O_{12}$. Manufactured samples were analyzed by TGA, XRD, SEM, PSA. Battery cycler was used to test the charge/discharge properties of active materials. Heat treatment temperature of $800^{\circ}C$ was needed to make a stable structure of $Li_4Sn_xTi_{5-x}O_{12}$ and the particle size distribution was $0.2{\sim}0.6\;{\mu}m$. Charge/discharge process was repeated for 50 cycles at room temperature. The initial capacity was 168mAh/g and the voltage plateau was observed at 1.55V(Li/$Li^+$).

• Clean Technology
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• v.21 no.4
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• pp.265-270
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• 2015

In order to increase the capacity of the lithium ion battery, the capacity of the anode should be increased. SnO₂ and Li₄Ti₅O₁₂ were studied to replace the graphite as the anode materials. In this study, SnO₂/Li₄Ti₅O₁₂ composite materials were synthesized by solid-state method. The study reported here attempts to enhance the electrochemical capacity of Li₄Ti₅O₁₂ through the incorporation of SnO₂. Sn-based Li ion storage materials are loaded on Li₄Ti₅O₁₂ surface. The SnO₂/Li₄Ti₅O₁₂ composite material has higher capacity than Li₄Ti₅O₁₂, but the cycling capacity was decreased due to SnO₂.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.268-268
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• 2009

Li-Mn spinel의 고온수영 특성을 향상을 위해 졸-겔법으로 $V_2O_5$를 Li-Mn spinel 표면에 코팅을 하였다. $V_2O_5$의 코팅양은 1, 3, 5wt%로 조절하여 코팅 양에 따른 특성변화를 조사하였다. XRD분석결과 $V_2O_5$가 코팅된 Li-Mn spinel을 $400^{\circ}C$에서 열처리시 $Mn(VO_3)_2$가 생성되는 것을 확인하였다. 충방전 테스트결과, 고온에서 $V_2O_5$를 코팅한 Li-Mn spinel이 우수한 수명을 나타냈다. 하지만 코팅량이 1wt%까지는 용량의 변화가 거의 없었고, 5wt% 코팅시 현격히 용량이 감소하였다.

• 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.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.200-205
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• 1993

We generated the second harmonic of Ti:sapphire laser in LiI$O_3$ and BBO crystals. Two LiI$O_3$, crystals and a BBO crystal were used, and the lengths of LiI$O_3$ crystals were 5, 10 mm and that of BBO was 7 mm. We measured the conversion efficiencies of LiI$O_3$ and BBO in the wavelength range of 780-810 nm, and compared with the caculation of theory. The measured second harmonic conversion coefficients were (1.06${\pm}0.05){\times}10^4\;W^1$(10mm), (5.28${\pm}0.33){\times}10^5\;W^1$(5mm), and (2.96${\pm}0.05){\times}10^5\;W^1$(BBO, 7 mm) at the fundamental wavelength of 794 nm.