Effect of PVdF Binder Content on Dry-Sprayed Graphite Electrodes for Lithium-Ion Batteries for Electric Vehicle Applications

Abstract This study explores the fabrication of graphite/PVdF electrodes using electrostatic dry spray-coating, a solvent-free and energy-saving process. We analyzed the effects of different PVdF concentrations (1.5%, 3.0%, and 4.0% in weight) on the morphology, mechanical properties, and electrochemical performance of the electrodes fabricated. We found that increasing PVdF binder concentration enhances mechanical properties such as peel strength, elastic modulus, and hardness due to improved particle cohesion and mechanical interlocking. However, it also increases electrical resistivity and tortuosity, as the insulating binder disrupts electronic conduction pathways and obstructs ion diffusion. These properties were quantitatively linked to several morphological parameters: the fraction of PVdF covering graphite particles, the volume and contact surface area of PVdF agglomerates. An optimal PVdF concentration is crucial for balancing these properties. The electrode with 3.0% stands out, delivering superior performance with a delithiation capacity of 193 mAh g-1 and a capacity retention of 97% at the 100th cycle in 4 mAh cm-2 pouch-cell format full cells.