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

Abstract

ABSTRACT 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.