Challenges and Opportunities for Large-Scale Electrode Processing for Sodium-Ion and Lithium-Ion Battery

Sodium-ion batteries are an emerging technology that is still at an early stage of development. The electrode processing for anode and cathode is expected to be similar to lithium-ion batteries (drop-in technology), yet a detailed comparison is not published. There are ongoing questions about the influence of the active materials on processing parameters such as slurry viscosity, coating thicknesses, drying times, and behavior during fast drying. Herein, the expected drying time for the same areal capacity of anodes (graphite vs. hard carbon) and cathodes (lithium iron phosphate vs. Prussian blue analogs) are compared based on respective specific capacities reported in the literature. Estimates are made for the materials' impact on production speed or dryer length. Within the experimental part, water-based slurries of the same composition are mixed using different active materials according to identical procedure and the viscosity is compared. When drying at a constant drying rate (0.75 g m-2 s-1), lithium iron phosphate electrodes with different areal capacities (1-3 mAh cm-2) are shown to have the highest adhesion. For high drying rates (3 g m-2 s-1) at constant areal capacity, especially the investigated electrodes based on hard carbon show that no binder migration occurs. LIB vs. SIB: This paper compares the expected drying time, production speed, dryer length based on specific capacities from the literature. For the same production speed, the drying time for SIB materials needs to be reduced. For a very high drying rate, especially the investigated hard carbon shows that no binder migration occurs.image