报告题目：Ion transport in lithium-ion conducting solid electrolytes: Oxides and composites
报 告 人：郭新 教授
郭新，华中科技大学材料学院教授，中国固态离子学会理事，国际期刊 “Solid State Ionics”编委，国际固态离子学会（International Society for Solid State Ionics）学术奖评审委员。回国前任德国于利希研究中心（Research Center Juelich）终身高级研究员，之前，他曾在德国马普固体研究所（Max Planck Institute for Solid State Research）从事研究工作多年。2005年获美国陶瓷协会Ross Coffin Purdy Award。在国际学术会议（如MRS, E-MRS, ECS, MS&T, SSI等）及国际著名高校和研究机构（如麻省理工学院、斯坦福大学、瑞士联邦工学院、德国马普研究所等）作过数十场邀请报告，并多次在国际会议上担任分会主席。在包括“Science”的学术期刊发表论文百余篇。研究领域可概括为“固态离子导体与混合导体及其在信息、环境与能源等领域的应用”，具体研究领域有: 1. 人工智能器件，2. 全固态锂电池，3. 气敏传感器。
In this talk, I am going to discuss a few issues about the ion transport in oxide ceramics with garnet and perovskite structures, and oxide-polymer composites. These issues include:
1. Ionic conduction in the grain bulk of Li7La3Zr2O12 (LLZO) garnets, and the strategy to enhance the ionic conductivity by proper doping. Herein, the influence of Ga doping on the properties of LLZO garnets is investigated, with the determined concentration and mobility of lithium ions shedding light on the origin of the high conductivity of Li7-3xGaxLa3Zr2O12.
2. Physical origin of the low grain boundary conductivity of Li3xLa0.67-x0.33-2xTiO3 (LLTO, 0.12 ≤ 3x ≤ 0.50, represents the A-site vacancy). Although the bulk conductivity of LLTO perovskites reaches the level of 10-3 S/cm, the grain boundary conductivity is orders of magnitude lower; the origin of the low grain boundary conductivity should be understood as a prerequisite to improve the overall conductivity.
3. Ionic conduction in oxide-polymer composites. Oxides often exhibit a high ionic conductivity, large electrochemical window and favorable thermal stability, but high brittleness. However, polymers are flexible, but suffer from low ionic conductivity, small ionic transference number as well as poor thermal and electrochemical stability. A fundamental strategy to address the above issues is to develop oxide-polymer composites, in which oxide particles are dispersed in the polymer matrix. The composite shows higher flexibility than ceramic oxides, meanwhile the ionic conductivity, ionic transference number and electrochemical stability are much higher than those of polymers. We use the LLZO-PEO composite as a model system and develop a conduction model based on the two-phase mixture theory.