• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.194-198
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• 2022

All-solid-state thin-film battery can realize the integration of electronic circuits into small devices. However, a high voltage cathode material is required to compensate for the low energy density. Therefore, it is necessary to study all-solid-state thin-film battery based on the high voltage cathode material LNMO. Nevertheless, the electrochemical properties deteriorate due to the problem of the interface between LiNi_0.5Mn_1.5O₄ (LNMO) and the solid electrolyte LiPON. In this study, to solve this problem, amorphous V₂O₅ was deposited as an interlayer between LNMO and LiPON. We confirmed the possibility of improving cycle performance of LNMO based thin-film battery. We expect that the results of this study can extend the battery lifespan of small devices using LNMO based all-solid-state thin-film battery.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.437-443
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• 2019

All-solid-state thin-film lithium-ion batteries are important in the development of next-generation energy storage devices with high energy density. However, thin-film batteries have many challenges in their manufacturing procedure. This is because there are many factors, such as substrate selection, to consider when producing the thin film multilayer structure. In this study, we compare the fabrication and performance of all-solid-state thin-film lithium-ion batteries with a $LiNi_{0.5}Mn_{1.5}O_4$ cathode/LiPON solid electrolyte/$Li_4Ti_5O_{12}$ anode structure using stainless steel and Si substrates with different surface roughness. We demonstrate that the smoother the surface of the substrate, the thinner the thickness of the all-solid-state thin-film lithium-ion battery that can be made, and as a result, the corresponding electrochemical characteristics can be improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.228-231
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• 1999

The preparation and electrical properties of LIPON electrolyte were investigated in order to fabricate all solid state thin film battery. The LIPON thin film was deposited by r.f. sputtering of Li$_3$PO$_4$ target in O$_2$-N$_2$ mixtures. The LIPON deposited at N$_2$+10% O$_2$ ratio had a conductivity at 25 $^{\circ}C$ of 1.8${\times}$10$\^$-6/S/cm. The ion conductivity of the LIPON films decreased as the O$_2$ content of the process gas increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.159-162
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• 1999

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$_2$O$\sub$5/Pt. The vanadium oxide thin films were formed by d.c. reactive sputtering on Pt current collector. After deposition of vanadium oxide films, in-situ growths of lithium phosphorus oxynitride film were conducted by r.f. sputtering of Li$_3$PO$_4$ target in mixture gas of N$_2$ and O$_2$. The pure metal lithium film was deposited by thermal evaporation on thin film LiPON electrolyte. The cell capacity was about 45${\mu}$Ah/$\textrm{cm}^2$ $\mu\textrm{m}$ after 200 cycle. No appreciable degradation of the cell capacity could be observed after 50 cycles .

• 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.

• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.593-598
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• 2004

To make the all-solid-state lithium thin film battery having less than 1 fm in thickness, LiCoO$_2$ thin films were deposited on Pt/TiO$_2$/SiO$_2$/Si substrate as a function of Li/Co mole ratio and the deposition temperature by Pulsed Laser Deposition (PLD). Especially, LiCoO$_2$ thin films deposited at 50$0^{\circ}C$ with target of Li/Co=1.2 mole ratio show an initial discharge capacity of 53 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 67.6％. The microstructural and electrochemical properies of (Li, La)TiO3 thin films grown on LiCoO$_2$Pt/TiO$_2$/SiO$_2$/Si structures by Pulsed Laser Deposition (PLD) were investigated at various deposition temperatures. The thin films grown at 10$0^{\circ}C$ show an initial discharge capacity of approximately 51 $\mu$Ah/cm$^2$-$\mu$m and moreover show excellent discharge capacity retention of 90％ after 100 cycles. An amorphous (Li, La)TiO$_3$ solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium thin film battery below 1 $\mu$m.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.409-409
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• 2011

All solid-state thin film lithium batteries have many applications in miniaturized devices because of lightweight, long-life, low self-discharge and high energy density. The research of cathode materials for thin film lithium batteries that provide high energy density at fast discharge rates is important to meet the demands for high-power applications. Among cathode materials, lithium manganese oxide materials as spinel-based compounds have been reported to possess specific advantages of high electrochemical potential, high abundant, low cost, and low toxicity. However, the lithium manganese oxide has problem of capacity fade which caused by dissolution of Mn ions during intercalation reaction and phase instability. For this problem, many studies on effect of various transition metals have been reported. In the preliminary study, the Sn-substituted LiMn2O4 thin films prepared by pulsed laser deposition have shown the improvement in discharge capacity and cycleability. In this study, the thin films of LiMn2O4 and LiSn0.0125Mn1.975O4 prepared by RF magnetron sputtering were studied with effect of deposition parameters on the phase, surface morphology and electrochemical property. And, all solid-state thin film batteries comprised of a lithium anode, lithium phosphorus oxy-nitride (LiPON) solid electrolyte and LiMn2O4-based cathode were fabricated, and the electrochemical property was investigated.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.93-93
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• 1997

• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.49.1-49.1
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• 2004

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.100-105
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• 2001

An all solid-state thin film battery (TFB) was fabricated by growing, undoped and Pt-doped vanadium oxide cathode film ( $V_2$ $O_{5}$ ) on I $n_2$ $O_3$: Sn coated glass, respectively. Room temperature charge-discharge measurements based on Li/Lipon/ $V_2$ $O_{5}$ full-cell structure with a constant current clearly shows that the Pt-doped $V_2$ $O_{5}$ cathode film is superior, in terms of cyclibility. X-ray diffraction (XRD) results indicate that the Pt doping process induces a more random amorphous structure than an undoped $V_2$ $O_{5}$ film. In addition to its modified structure, the Pt-doped $V_2$ $O_{5}$ film has a smoother surface than the undoped sample. Compared to an undoped $V_2$ $O_{5}$ film, the Pt doped $V_2$ $O_{5}$ cathode film has a higher electron conductivity. We hypothesize that the addition of Pt alters electrochemical performance in a manner of making more random amorphous structure and gives an excess electron by replacing the $V^{+5}$. Possible mechanisms are discussed for the observed Pt doping effect on structural and electrochemical properties of vanadium oxide cathode films, which are grown on I $n_2$ $O_3$: Sn coated glass.