Exploring Interfaces in Li-ion All-Solid-State Batteries

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The necessary transition towards renewable energy resources requires the development of safe, reliable, and cost-efficient energy storage systems. However, the dominating commercial lithium batteries are usually based on liquid electrolytes (media that transports lithium ions during charge and discharge) that are flammable and/or toxic.One promising alternative to the current standard are solid electrolytes (SEs), the use of which would result in All-Solid-State Batteries (ASSBs). Unlike their liquid counterparts, SEs do not pose the same flammability and toxicity risks. To date, only little is known about the chemical mechanisms that underpin parameters such as Li-ion transport in solid electrolytes, the structures and compositions formed both in the active materials and their interfaces during synthesis and operation, and how the microscopic properties of the starting materials influence the electrochemical performance.The main goal of the research project is to provide insight into the reaction mechanisms at the interfaces within an ASSB in order to improve their performance. We will focus on realistic mixtures consisting of active materials (that can store lithium and thus energy) and SEs instead of only pure materials. We aim to use powder X-ray diffraction, solid state NMR spectroscopy, and electron microscopy to provide molecular-level insight into the chemical mechanisms related to structural and dynamic changes during synthesis as well as operation of ASSBs. The understanding of these mechanisms will lead to optimized ASSBs with improved capacity retention, charging rates, and lifetime.