Basic study for the fabrication of all solid lithium battery

全固态锂二次电池作为具有高性能的新型电源被强烈期望，因为这些无溶剂系统比具有液体电解质的常规锂二次电池具有更高的安全性和更高的可靠性。Thio-LISICON（锂超离子导体），Li 4-x Gel-x Px S4是无机材料中发现的最好的锂离子导电固体之一，具有足够高的电导率，传输数，分解电位和热稳定性，可用于电池中的实际应用。本研究的目的是开发在高电流密度下具有优异充放电性能的全固态电池，并表征各种阳极/电解质界面的界面行为。通过X射线衍射、X射线光电子能谱、交流阻抗和扫描电子显微镜分析，发现在Li-Al合金/Li3.25Ge0.25P0.75S4界面处存在固体电解质界面。以层状岩盐型LiMO_2（M=Co，Ni）和尖晶石型LiMn_2O_4氧化物为阴极材料，研究了锂离子电池嵌锂电极的表面反应和反应机理。用PLD法在SrTiO_3单晶衬底上成功地制备了电极薄膜。外延膜的取向由衬底取向控制。通过同步辐射X射线衍射和反射率测量，阐明了它们的嵌锂反应和表面反应的各向异性特征。

All-solid state lithium secondary batteries are strongly desired as novel power sources with high performances because these solvent-free systems have higher safety and higher reliability than conventional lithium secondary batteries with liquid electrolytes. Thio-LISICON (LIthium SuperIonic CONductor), Li4-x Gel-x Px S4 is one of the best lithium ion conductive solids ever found in inorganic materials, and has sufficiently high conductivity, transport number, decomposition potential and thermal stability for practical use in battery. The purpose of the present study is to develop the all solid-state battery having excellent charge-discharge performance at high current density, and to characterize the interfacial behavior at various anode/electrolyte interfaces. The solid electrolyte interface (SEI) was found at Li-Al alloy/Li3.25Ge0.25P0.75S4 interface by x-ray diffraction pattern, x-ray photoelectron spectroscopy, ac impedance, and scanning electron microscopy. The SEI allowed the fastest electrochemical reaction between the anode and the electrolyte during charge-discharge process.The surface reaction and reaction mechanism of the lithium intercalation electrodes were studied using epitaxial cathode films of LiMO_2 (M=Co, Ni) and LiMn_2O_4 oxides with the layered rock-salt type and the spinel structure, respectively. The electrode films were successfully deposited on single crystal SrTiO_3 substrates by PLD method. The orientation of the epitaxial films was controlled with the substrate orientation. The anisotropic characteristics of lithium intercalation reaction and surface reaction for their cathode materials were clarified by in-situ synchrotron X-ray diffraction and reflectivity measurements in beam-line 14B1 at SPring-8.