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At present, we suffer from various environmental issues such as air pollution and rapid weather change. Air pollution is usually caused by the use of fossil fuels. To overcome the environmental issues, LIBs are reasonable candidates. In these days, lithium ion batteries (LIB) are very promising power suppliers for electronic devices, electrical vehicles (EV), and energy storage system (ESS) because of their high power densities.[1] Although the LIB has advantages compared to other power sources, LIBs with a liquid electrolyte have safety issues such as explosion and fire contributed by thermal or chemical instability. All-solid-state batteries are the solution to the problem of LIBs with liquid electrolytes. All-solid-state batteries have many advantages such as high energy densities, high stability, and applying high voltages compared to conventional LIBs.[2] As the portable and miniaturization of electronic devices and the development of wearable devices are to be in the spotlight, the development of a power supply for drive them is indispensable. The type of batteries that can meet this demand is an all-solid-state thin-film battery. Thickness of thin-film batteries is about 10 μm, which makes it suitable for power source of miniaturized electronic devices such as smart cards, RFID tags and medical devices. All-solid-state thin-film batteries also have better thermal stability than conventional Li-ion batteries. Higher capacity of thin-film batteries can be realized by applying high voltages. The key to the performance of all-solid-state thin-film batteries is a solid electrolyte. In order to deposit thin-film electrolytes, there are various available techniques such as a sputter, plasma laser deposition (PLD), e-beam evaporator, and so on. Among these techniques, the sputtering technique has an advantage compared to other deposition techniques. The sputtering techniques could deposit oxide and nitride materials. In addition, sputtering techniques are simple process and can be deposition with thin films uniformly. Comparing PLD and molecular beam epitaxy (MBE), the sputtering techniques are lower cost and low temperature for deposition. Therefore, sputters are suitable for commercialization. Generally, solid electrolytes are classified under oxide system and sulfide system. While sulfide electrolytes have high ionic conductivity and instability, oxide electrolytes have low ionic conductivity and high stability. A lot of oxide based solid state electrolytes were researched. The oxide-based solid electrolytes include LiPON, Li7La3Zr2O12 (LLZO), Li1+xAlxTi2-x(PO4)3(LATP), and lithium boron oxynitride. Among them, LiPON thin-film electrolytes are representative and commonly used as a thin-film electrolyte. However, since the ionic conductivity of LiPON is relatively low, it is necessary to improve the low ionic conductivity. In this study, a new lithium silicon oxynitride (LiSiON) thin-film electrolyte was deposited by RF sputtering technique. Surface morphologies and cross-sectional views of the thin-film electrolyte were characterized by field emission scanning electron microscope (FESEM). The thin film showed smooth surface without any cracks and pinholes. It can be thought that the smooth surface could decrease interfacial resistance between electrolyte and electrodes. In addition, surface morphologies were also characterized by atomic force microscopy (AFM). The sputtering rates were calculated by thickness of thin films on cross sectional views. Structural properties of the thin films were characterized by x-ray diffraction (XRD). The thin film showed amorphous properties compared to the target material which is a crystalline material. In addition, structural properties of the thin film were also characterized by transmission electron microscope (TEM). The thin film showed also amorphous properties with partially crystalline in LiSiON structures deposited by RF sputtering. Ionic conductivity of LiSiON was measured by electrochemical impedance spectroscopy (EIS). Cu thin films used as blocking electrodes with 150nm thickness were deposited by a direct current (DC) magnetron sputtering using a target with 2-inch diameter. The DC power and working pressure were set on 30W and 7 mTorr in Ar atmosphere, respectively. LiSiON thin film was deposited by an RF magnetron sputter at 200W power using Li4SiO4 target with 4-inch diameter in Ar/N2 (2:8) atmosphere. Ionic conductivity of the LiSiON thin film showed 2.47 ´ 10-6 (S/cm) which is similar to other lithium oxide thin films. For this reason, LiSiON thin-film electrolytes are research-worthy materials for use in all-solid-state thin-film batteries. Reference [1] M. Armand, J. Tarascon, Nature, 451, 652 (2008). [2] Q. Wang, P. Ping, X. Zhao, G. Chu, J. Sun, et al., J. Power Sources, 208, 210 (2012).

The necessity of developing new types of energy conversion and storage systems is evident by the rapidly decreasing fossil fuels and the continuously growing environmental issues. Coupling of lithium ion secondary batteries and photovoltaic cells is a reasonable candidate of new types of energy transform and storage system to reduce environmental concerns. Solar cells can ensure sustainable access to electrical power for charging LIBs anywhere around the world with no air pollution, hazardous waste or noise. Accordingly, the solar cell technology that generates electricity from the sunlight [1], could offer a viable approach to ‘self-charging’ of LIBs. However, most current solar cells, especially polymer solar cells, generally show low current densities and power conversion efficiencies, and to improve this we used perovskite solar cell for power supply of self-chargeable batteries. The recent availability of high-performance perovskite solar cells (PSCs) could not only facilitate the development of highly efficient (up to ~ 20 %) [2] and low cost solar cells for practical applications but also allow for the integration of PSCs into various energy systems. One of the important problems of PSC-LIB coupling is that when charging, the voltage of the PSCs must be higher than the operating voltage of the LIBs. If the above conditions are not established, PSCs may cause discharge of the LIBs. The most structurally stable LiFePO4(LFP)-LTO(Li4Ti5O12) batteries were used for coupling. In the case of LFP-LTO batteries, the OCV(open circuit voltage) value has a low voltage of 1.85V. It was confirmed that stable self-charging is achieved by connecting it to a manufactured PSCs pack with a charging voltage of 2.1 V. This work clearly indicates that the PSC-LIB units developed in this study hold great promise for potential applications as self-chargeable batteries to various portable electronics. In this study, we have fabricated lithium-ion pouch cell and coin cell based on LFP and (LTO) as a cathode and an anode, respectively. The cathode was fabricated by blending LFP powder with carbon black (Super P) and polyvinylidene difluoride (PVDF) at a weight ratio of 8:1:1. The anode was also prepared in the same way as the cathode using LTO powder and N-Methyl-2-pyrrolidone (NMP) was used as the solvent, respectively. The Electrolyte was used 1.2 M LiPF6 in a 1:1(v/v, %) mixture of ethylene carbonate and dimethyl carbonate. Pouch cell was fabricated with size of 3 cm x 5 cm. Ni and Al were used as cathode and anode lead tabs, respectively. The LIBs were assembled as the CR 2032 coin-type cells and pouch cells in an Ar-filled glove box. Structural properties and chemical compositions of LFP and LTO powders were investigated by x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The XRD pattern shows that the LiFePO4 cathode sheets are crystalline. The powder and surface morphologies of electrode sheet were characterized by FE-SEM. The primary particles size was identified as approximately 50 to 150 nm and the secondary particles size approximately 10mm. The electrochemical performance of LFP and LTO half cells and the LFP-LTO full cell were conducted by cyclic voltammetry and charge/discharge cycle tests at various current densities in the voltage ranges. Electrochemical impedance spectroscopy (EIS) was performed in frequency range from 0.1 Hz to 1 MHz, using 10 mV ac signals at room temperatures. LFP-LTO pouch cells showed good cycling stability a wide range of C-rates from 0.1 to 1.0 C with charge/discharge capacities of 142/138 mAhg-1 at 0.1 C and 152/144 mAhg-1 at 1.0 C. As a result, LiB-PSC coupling enabled the implementation of self-chargeable batteries. Finally, Perovskite solar cells and the Li-ion battery coupling were tested for a self-chargeable device. References Green, M. A. Solar cells: Operating Principles, Technology, and System Applications (Prentice-Hall, 1982). Lee, M. M., Teuscher, J ., Miyasaka, T., Murakami, T. N. & Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338, 643-647 (2012)

The advent of ubiquitous computing environments enables users to access their digital contents when they want at any time once their devices are connected to the Internet. For efficient management of remote contents, we need a replication technique among servers. However, th existing approaches focus on shared contents using the access heuristics of groups of users. In this paper, we propose a personalized replication scheme especially for contents owned by one user. The proposed scheme selects target replication servers according to both the user’s past behavior and future movement plan. We periodically analyze each user’s access location in order to figure out where the user usually accesses contents. A user also can register his/her schedule information on personal or business trips to our system, which then expects that the user will be likely to access contents at a different location during the specified dates. With this simple reasoning, our replication scheme additionally replicates contents to another replication server near to the user’s destination. Simulations show that the proposed scheme reduces the expense of storage usage because we replicate contents only to selective servers, and it keeps content access time low because contents are accessed from nearby replication servers with high probability based on the user’s past and future location information. The proposed approach can be applied to distributed storage and personal content synchronization applications. Especially, it is appropriate to storage service for a photographer, who travels all over the world and deals with large amount of photograph data. As personal content management has been one of promising services in cloud computing systems, we expect that the proposed scheme also can be adopted in cloud computing nodes in order to efficiently manage contents as well.