GeS2-Ga2S3-Li2S-LiI硫化物玻璃陶瓷的锂离子传输特性与机理研究

研制具有高锂离子电导率的硫化物固态电解质是发展新一代高安全性、大容量锂硫电池的重要途径。本项目以具有较好化学稳定性的GeS2-Ga2S3-Li2S-LiI体系为研究对象，拟利用高能球磨非平衡制备手段，突破传统玻璃形成区限制，在更宽成分范围内优化玻璃相离子电导，同时利用微晶化处理协同发挥微晶玻璃的离子传输增强效应，获得高离子电导率的硫化物固体电解质。为区分玻璃相与微晶相在微晶玻璃总离子电导中的贡献，阐明各自的离子传输机理，本项目一方面在扩大的成玻区内研究玻璃近程、中程结构以及离子传输特性随成分的变化趋势，从而以玻璃网络结构的角度分析玻璃相离子传输机制；另一方面在实现可控微晶化的基础上，着眼于研究微晶/玻璃相界面的微观结构与局部离子电导的关系、三维拓扑结构与整体平均电导的关系，以期揭示由相界面构成的离子传输通道在微晶玻璃离子电导中的关键作用。本项目研究有望为理解硫化物玻璃/微晶玻璃中的离子传输

Research on chalcogenide solid state electrolyte with high ionic conductivity is a very important way to develop high security and large capacity Li-S batteries. In this project, a chemically stable system GeS2-Ga2S3-Li2S-LiIis supposed to be researched. The ionic conductivity in glassy phase will be optimized in a broader glass forming region whose limit could be broken by high-energy milling synthesis. Glass-ceramic phase formed by controllable crystallization can be cooperated with to play the ionic transport enhancement effect. Consequently, chalcogenide solid state electrolyte with high ionic conductivity could be synthesized. .In order to distinguish the contribution to conductivity from glassy phase or glass-ceramic phase and to clarify the mechanism of ionic transport, in the one hand, the composition dependence of the short/medium-range structure and the ionic transport characteristics of the glassy phase will be studied in the enlarged glass forming region, so that the ionic transport mechanism in glassy phase could be analyzed in the view of glass network structure. In the other hand, on the base of controllable crystallization, the two relationships, i.e., microstructure of crystallite/glass interface – local ionic conductivity, and 3D topology structure –bulk average ionic conductivity, will be focused on to reveal the key role of ionic transport pathway formed by interfaces in the glass-ceramic ionic conduction. This project is expected to achieve a profound understanding on the ionic transport in chalcogenide glass/glass-ceramic.