Novel ceramic-polymer hybrid electrolytes for Li-ion solid state batteries: interrelation of interface structure and morphology with ion transport

基于锂离子技术的固态电池是高能量密度、安全稳定的存储设备的潜在候选者。开发这种电池的一个主要问题是制造合适的复合阴极。需要材料和加工解决方案来为电极提供高导电性，以便将欧姆损耗降至最低，并提供弹性来补偿体积变化。此外，最好使用单离子电解液，以避免极化效应。该方案旨在研究用于固态锂离子电池的新型无机-有机杂化固体电解质，主要用作复合正极中的阴极。从概念上讲，混合电解质可以结合结晶电解质的优点(高电导率)和聚合物电解质的优点(弹性)。这一概念的主要挑战是在复合材料内提供与两种不同组成材料的块体和界面属性相关的高导电性通道。我们的方法是将具有改进的体积性能的聚电解质与具有合适的形貌和表面化学的陶瓷电解液颗粒相结合，以制备具有高锂离子导电性和良好的力学性能的复合材料。因此，陶瓷电解液颗粒的表面化学被超薄涂层修饰，目的是改善穿过(或沿)陶瓷-聚合物界面的传输。该项目的一个主要目标是建立界面结构和形态与离子传输的相互关系。为了理解与界面相关的锂离子输运现象，利用表面科学方法和电化学技术对二维模型界面(层堆栈)进行了界面形成和性质的基础研究。

Solid state batteries based on Li-ion technology are promising candidates for high energy density, safe and stable storage devices. A major issue for the development of such batteries is the manufacture of suitable composite cathodes. Material- and processing solutions are required to provide the electrode with high electric conductivity in order to minimize ohmic losses as well as provide elasticity to compensate volume changes. Also, single-ion electrolytes are preferred to avoid polarization effects. This proposal aims to investigate novel inorganic-organic hybrid solid state electrolytes for use in solid state Li-ion batteries, mainly as catholyte in the composite cathode. Conceptionally, hybrid electrolytes can combine the advantages of crystalline electrolytes (high conductivity) with the advantages of polymer electrolytes (elasticity). A major challenge for such a concept is to provide high conductivity channels within the composite, related to bulk and interface properties of the two different component materials. Our approach is to combine polyelectrolytes with improved bulk properties and ceramic electrolyte particles with suitable morphology and surface chemistry to fabricate composites with high Li-ion conductivity and good mechanical properties. The surface chemistry of the ceramic electrolyte particles is thereby modified by ultra-thin coatings with the aim to improve the transport across (or along) ceramic-polymer interfaces. A major aim of the project is to establish the interrelation of interface structure and morphology with ion transport. In order to understand interface-related Li-ion transport phenomena, fundamental investigations towards interface formation and properties is performed by means of 2D model interfaces (layer stacks), which are characterized by surface science methods and electrochemical techniques.