Enhancing Binder Dispersion and Fibrillation in Lithium-Ion Battery Dry-Coated Cathodes via Graphene-Based Interfacial Engineering

Dry battery electrode (DBE) manufacturing avoids energy-intensive solvent evaporation and recapture while enabling high areal capacity and active material fraction for enhanced lithium-ion battery energy density. Shear-based fabrication of DBEs relies on fibrillation of polytetrafluoroethylene (PTFE) binder to support free-standing electrodes. Here, we use graphene-coated cathode active material (NMC811, LiNi0.8Mn0.1Co0.1O2) to improve PTFE fibrillation, carbon nanofiber dispersion, and cathode cohesion, while minimizing binder content and providing stability to 4.4 V. We identify that graphene-coated NMC811 strengthens interfacial interactions with PTFE compared to uncoated NMC811, driving enhanced PTFE fiber formation for strongly cohesive cathodes with 0.3 wt% PTFE. Exploiting this improved PTFE fibrillation, we fabricate thick, graphene-coated NMC811 DBEs with 99.2 wt% active material and high areal capacity (> 10 mAh/cm2, 170 µm thick) that possess high mechanical integrity and stable electrochemical cycling. Our findings demonstrate interfacial engineering as a key design variable for realizing high-energy-density DBEs with minimal inactive additives.