Visualising the Effect of Areal Current Density on the Performance and Degradation of Lithium Sulfur Batteries Using Operando Optical Microscopy

The degradation of lithium sulfur (Li-S) batteries poses significant challenges to their commercial viability and occurs largely due to the complex electrochemical reactions and structural transformations that take place during charge-discharge cycles. This study employs optical microscopy techniques to investigate and quantify the degradation mechanisms in Li-S batteries. By capturing high-resolution, time-lapsed images of both electrodes and the electrolyte-filled interelectrode space, key morphological changes can be identified and analysed, such as the formation and growth of lithium dendrites, sulfur dissolution, and electrode-electrolyte interface degradation. Quantitative image analysis is conducted to measure the extent of these changes, providing insights into their impact on battery performance. Our findings reveal critical correlations between specific morphological features and electrochemical inefficiencies, contributing to a deeper understanding of the degradation pathways in Li-S batteries. This optical microscopy approach offers a non-destructive, cost-effective, real-time method to monitor battery health, potentially guiding the development of more durable and efficient Li-S batteries.