Unveiling the Structural Advantages in PTFE-Based Dry-Processed Electrodes for Sulfide-Based All-Solid-State Batteries via 3D Microstructure-Resolved Analysis.

All-solid-state batteries (ASSBs) employing sulfide-based solid electrolytes (SEs) are promising candidates for next-generation lithium-ion batteries owing to their high energy density and safety. Their electrochemical performance is strongly influenced by the electrode microstructure, and polytetrafluoroethylene (PTFE)-based dry electrode process has recently emerged as a promising strategy for constructing favorable electrode structure while offering a low-cost, energy-efficient, and eco-friendly approach. However, the structural characteristics of PTFE-based dry-processed electrodes remain insufficiently understood. Here, we quantitatively elucidate their structure through 3D digital twins reconstructed from high-resolution FIB-SEM tomography. Incorporation of 0.2 wt.% PTFE induced SE coating on cathode active material particles, increasing surface coverage from 35% to 59%. Moreover, it promoted a more homogeneous spatial distribution of all electrode components, establishing well-connected ion and electron transport pathways within the electrode. These PTFE-induced structural advantages yielded enhanced capacity and improved cycling stability. Even at the high mass loading of 45 mg cm-2, the 0.2 wt.% PTFE-incorporated dry-processed electrode delivered excellent areal capacities under high-rate conditions (6.42 mAh cm-2 at 3.6 mA cm-2), demonstrating strong potential for realizing high-energy-density ASSBs. These findings provide an in-depth understanding of the structural characteristics of PTFE-based dry-processed electrodes, offering a viable pathway toward the commercialization of practical, high-energy-density ASSBs.