Tracking Through-Thickness Dynamics in Lithium-Sulfur Batteries via Operando Raman Imaging and a Purpose-Built Cell

Abstract

Most existing operando methods lack the spatial resolution or measurement access required for cross-sectional analysis of battery electrodes. Here, we present a custom-designed operando electrochemical cell, enabling real-time, through-thickness investigations. Applied to a lithium-sulfur battery, this setup reveals gradual and spatially non-uniform sulfur utilization, dissolution, and reprecipitation. Depth-resolved measurements indicate highly nonuniform sulfur utilization, with earlier sulfur depletion near the current collector. Accessing the electrode cross-section provides critical insights into reaction heterogeneity and dynamics that are inaccessible via conventional measurements. This offers a deeper understanding of battery behavior and facilitates the design of cells with improved performance and durability.