Dry electrode coating technology is emerging as a lower cost and more sustainable alternative to traditional lithium-ion battery (LIB) manufacturing. Desire for lower cost cells is also driving interest and the selection of LFP as the active material. Dry coating technology offers benefits such as lower energy consumption, solvent-free processing, and reduced manufacturing footprint. Polytetrafluoroethylene (PTFE) fibrillation – a unique feature of this polymer – is required to cohesively bind electrode powder constituents in solvent-free manufacturing. Fibrillation is largely induced by shear and temperature; however, raw material selection, electrode process steps, and inherent binder properties may affect fibril formation and the resulting electrode properties.

Controlling PTFE fibrillation during solvent-free electrode manufacturing is critical to alleviate some of the challenges associated with the use of small particle (D50 ~ 1µm) active materials, such as LFP. The challenge with small particle active materials is that they lead to poor film cohesiveness and poor mechanical properties, due to inhomogeneous powder dispersion and poor fibril networks. Small particles can disrupt the uniform distribution of binder and other constituents and negatively affect electrode cohesion, flexibility, and overall performance metrics.

Herein, we highlight property – performance relationships for advanced fluoropolymer binders developed for small particle active material systems, such as LFP. By leveraging a combination of high-resolution microscopic techniques and rapid in-line characterization methods, this research systematically investigates how the degree of PTFE fibrillation impacts the electrode structure and properties. This work provides guidance for incorporating advanced fluoropolymer binders in small particle active material systems to advance dry electrode technology, enabling more reliable, high-performance, and environmentally sustainable industrial LIB electrode production.