Industrial dry coating of NMC battery electrodes enabled by continuous extrusion mixing

Dry coating of battery electrodes is a promising technology for reducing the environmental footprint and the cost of lithium-ion battery cell manufacturing. However, obtaining a homogeneous electrode microstructure without a solvent is a key challenge. Here, we demonstrate the potential of twin-screw extrusion as a solvent-free, continuous dry-mixing method enabling precise polytetrafluoroethylene (PTFE) fibrillation and carbon black dispersion during NMC electrode production. Through in-depth microstructural characterization, we reveal a strong correlation between the microstructure of the extrudates and the calendered electrodes, underscoring the crucial role of mixing in controlling microstructure. Electrochemical cycling of high-areal-capacity (5.9 mAh cm-2) dry-coated NMC622 electrodes paired with graphite in coin cells yields 150 mAh g-1 upon discharge at C/2 with 79% capacity retention after 500 cycles. Our results highlight the industrial potential of twin-screw extrusion for continuous dry coating of battery electrodes.