Optimization of PTFE fibrillation in dry electrode process for scalable all-solid-state battery manufacturing

Abstract

This study investigates the scalability of the dry electrode process for all-solid-state battery (ASSB) cathodes, with a focus on optimizing fibrillation degree of polytetrafluoroethylene (PTFE) to improve the mechanical and electrochemical properties of the electrodes. Using a kneading time variation from 10 to 120 min, the degree of PTFE fibrillation was systematically controlled, showing that the optimized electrode achieved the highest discharge capacity (195.7 mAh/g) and excellent rate performance. Mechanical analysis revealed that excessive fibrillation weakened the electrode's tensile strength, while optimal fibrillation provided the best performance. The dry electrode process, achieved with only a few calendering cycles, demonstrated potential for mass production with a scalable roll-to-roll (R2R) approach, unlike previous lab-scale methods requiring repetitive film folding and calendering. The electrochemical performance of the optimized electrode in half-cell and pouch-type full-cell configurations further confirmed its superior capacity retention and stable cycling performance. These findings suggest that the dry electrode process is a promising method for the large-scale manufacturing of high-performance cathodes in all-solid-state batteries.