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。发展这种电池的一个主要问题是制造合适的复合阴极。材料和加工解决方案需要为电极提供高导电性，以尽量减少欧姆损耗，并提供弹性来补偿体积变化。此外，首选单离子电解质以避免极化效应。本课题旨在研究用于固态锂离子电池的新型无机-有机混合固态电解质，主要用作复合阴极的阴极电解质。从概念上讲，混合电解质可以结合晶体电解质的优点（高导电性）和聚合物电解质的优点（弹性）。这种概念的一个主要挑战是在复合材料中提供高导电性通道，这与两种不同组件材料的体积和界面特性有关。我们的方法是将具有改进体积性能的聚电解质和具有合适形态和表面化学性质的陶瓷电解质颗粒相结合，以制造具有高锂离子电导率和良好机械性能的复合材料。陶瓷电解质颗粒的表面化学因此被超薄涂层修饰，目的是改善跨越（或沿着）陶瓷-聚合物界面的传输。该项目的一个主要目的是建立界面结构和形态与离子输运的相互关系。为了理解与界面相关的锂离子输运现象，通过表面科学方法和电化学技术表征的二维模型界面（层堆栈），对界面形成和性质进行了基础研究。

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.