Dry Process for Green Manufacturing of Battery Electrodes: Structural Evolution of Freestanding Film During Roll-to-Roll Processing

Abstract The demand for cost-effective and sustainable battery manufacturing promotes interest in solvent-free electrode processing. Conventional slurry-based wet coating requires substantial energy for solvent evaporation and recovery, imposing process complexity and environmental burdens. By eliminating toxic organic solvents, dry electrode processing based on polytetrafluoroethylene (PTFE) fibrillation offers a sustainable alternative. Without solvents, structural formation depends on mechanical processes rather than liquid-phase assembly. This review examines the structural evolution of freestanding dry electrode films during roll-to-roll processing from a mechanical perspective. Force transmission mechanisms across mixing, kneading, grinding, and rolling are analyzed to establish how shear-driven PTFE fibrillation and compression-induced densification govern microstructure formation. Rolling-induced stress controls PTFE network formation and electrode mesostructure, which determines mechanical and electrochemical properties. Comparisons with slurry electrodes reveal fundamental structural differences in network formation. Also, we identify mechanical challenges for industrial scalability, including particle fracture during consolidation, tribological wear at processing interfaces, and process stability constraints. Extension to all-solid-state and lithium-sulfur batteries demonstrates cross-chemistry applicability of these mechanical design principles for sustainable manufacturing.