Dry Electrode Processing for Sodium-Ion Batteries: Transition from PFAS-Based to PFAS-Free Binders

The growing demand for advanced energy storage systems to address future challenges has intensified the search for alternative battery technologies. Sodium-ion batteries (SIB) have garnered significant attention due to their cost-effectiveness, evenly distributed raw materials, potential low cost, similarity to Lithium-ion-battery (LIB) chemistries, and convincing performance.[1] The optimization of the manufacturing process of SIBs can further increase economic and environmental competitiveness with modern LiFePO4-based batteries, e.g., by transitioning to low solvent or solvent-free processes. At the Fraunhofer ISE, by employing different innovative dry or semi-dry electrode processing techniques, we are able to demonstrate that PFAS-free binders can achieve comparable or superior electrochemical performance compared to PFAS-containing electrodes. The resulting electrodes exhibit tunable morphologies, including porosity control, adjustable layer thicknesses from µm to mm scale, and good structural stability. The developed (semi-)dry coating process for battery electrodes reduces the environmental impact associated with fluorinated materials. Overall, within this presentation, the findings highlight the effectiveness of PFAS-free binders in maintaining electrode integrity and enhancing overall battery performance.