Evanescent wave spectroscopy in Lithium-sulfur pouch cell with fiber optical sensors

Abstract

The demand for efficient and sustainable energy storage solutions has grown in recent years. Lithium-sulfur (Li-S) batteries have emerged as promising candidates due to their high energy density and potential for cost-effective energy storage. However, to harness their full potential, it is imperative to gain a deeper understanding of the electrochemical processes occurring within these batteries. This thesis tailored to calibrated the fiber optical sensors, delving into various aspects of electrolyte preparation, Ultraviolet–visible (UV-VIS) spectroscopy, fiber optical sensors, and operando measurements. The journey begins with the meticulous preparation of electrolyte solutions tailored to enhance Li-S battery performance. This thesis presents a novel approach to investigate the dynamic behavior of Li-S pouch cells through the application of evanescent wave spectroscopy (EWS) with fiber optical sensors. EWS allows for real-time, non-invasive monitoring of chemical species near the electrode-electrolyte interface, offering insights into key electrochemical phenomena such as sulfur dissolution and precipitation, polysulfide formation, and the shuttle effect. Within the controlled controlled argon atmosphere of a glovebox, we construct pouch cells, providing the foundation for our operando measurements. Finally, we utilize Pythonbased data evaluation techniques to make sense of the complex operando measurements, extracting meaningful conclusions that contribute to the ongoing evolution of Li-S battery technology. In summary, this thesis takes you on a comprehensive journey through the world of Li-S batteries, from the laboratory bench to the data analysis desk. This work contributes to the fundamental understanding of Li-S battery chemistry and paves the way for the development of next-generation energy storage systems with enhanced performance and durability.