快离子导体Li10GeP2S12结构与离子导电机理的核磁共振研究

项目名称： 快离子导体Li10GeP2S12结构与离子导电机理的核磁共振研究

项目编号： No.11474314

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 冯继文

作者单位： 中国科学院武汉物理与数学研究所

项目金额： 105万元

中文摘要： 超离子导体Li10GeP2S12是目前室温电导率最高的固体电解质。其结构特征为典型的一维Li 离子通道结构、且一维通道具有较高的空位浓度。除此之外，还可能存在连接一维通道的其它导电途径，从而形成导电的三维网络。本研究的目的是以超离子导体Li10GeP2S12作为模型化合物来研究与超离子导电性有关的结构要素和所涉及的一些重要的基本物理问题。首先，改进和发展直接测量离子对扩散的相关函数的NMR方法。在此基础上 研究一维通道中离子扩散性质：完全无规的离子扩散或协同离子迁移的基本规律和NMR特征，如绳索型（string-like）。探索一维导电到三维导电度越的可能途径和规律：通过骨架Li位点渗流通道；通过骨架间隙位点通道；阳离子迁移与阴离子集团的转动偶合（paddle-wheel模型）。为材料的改性以及设计和开发新一代高性能固体电解质提供依据。

中文关键词： 快离子导体；核磁共振；微观结构；导电机理

英文摘要： uperionic conductor Li10GeP2S12 exhibits the highest room-temperature ionic conductivity among the reported solid-state Li ionic electrolytes.The feature of the Li10GeP2S12 structure is its one-dimensional Li ionic channels in which vacancy concentration is high.Besides, there may also exist other ionic diffusion pathway which connects two adjacent one-dimensional channels to form the three-dimensional network. The purpose of this proposal is to investigate the key structural features relative to extremely high ionic conductivity and to understand some physical fundamentals of the present superionic conductor, by taking Li10GeP2S12 as a model compound. The first step is to improve and develop the NMR method for measuring the correlation function of diffusion of ionic pairs.The above methods are ued to investigate chacteristics of the ionic diffusion in one-dimensional channels: random ionic hop with a distribution of jump rates or cooperative ionic motion (such as string-like diffusion). Finally,we will explore the possible diffusion pathways associated with 1D-3D crossover: diffusion pathway connects Li sites on backbone and Li in channel; diffusion pathway connects interstitial sites on backbone and Li sites in channel; Li+ migration in dynamically coupled to anion reorientations(paddle-wheel model).

英文关键词： Fast ionic condutor;NMR;micro-structure;Conductive Mechanism