Effect of the Physicochemical Properties of PVdF on Dry-Sprayed Graphite Electrodes for Lithium-Ion Batteries for Electric Vehicle Applications

Abstract

Abstract We investigated the fabrication of graphite/PVdF anodes using electrostatic dry spray-coating, employing two different PVdF binders with different physicochemical properties such as primary particle size, crystallinity, melting temperature, and viscosity. We examine and compare the morphological, mechanical, electrical, and electrochemical properties of the dry-sprayed electrodes (DSEs). Significant differences were observed, particularly in terms of adhesion/cohesion, electrical resistivity, tortuosity, and electrochemical performance, with the PVdF binder characterized by a smaller particle size (178 nm) and a slightly higher melting temperature range (165–172°C), demonstrating superior long-term cycling stability. Specifically, the best electrode made with this binder achieved 188.3 mAh g-1 with over 94.9% capacity retention after 200 cycles. In contrast, the best electrode made with the PVdF binder with a larger particle size (270 nm) and a lower melting temperature range (155–172°C), showed a performance of 173.9 mAh g-1 with 88.3% capacity retention under the same conditions. Our findings highlight the necessity of adjusting fabrication conditions according to the specific characteristics of each PVdF binder to optimize the overall performance of the DSEs.