Water-Based PVDF Binder for Improved Performance and Stability of Batteries

PVDF, a partially fluorinated semi-crystalline polymer, is one of the preferred choices as binder material for electrodes thanks to its stable and reliable performance in terms of longer cycle life, better power performance and higher energy density. Moreover PVDF brings advantages to the lithium battery industry in the design of the separators. However, PVDF usually requires the use of solvent-based processing such as NMP, which is both costly and toxic. Solvay introduces a novel fluorinated binder in aqueous dispersion with proprietary chemical modification for improved performance (in terms of adhesion and chemical resistance) and a sustainable manufacturing process. Differently from any other PVDF-based system, this novel PVDF latex ensures continuous film of binder between active material particles. The chemical modification in PVDF ensures also improved higher and more stable adhesion in combination with flexibility (cohesion) of the final electrode. In negative electrode, taking advantage of PVDF binder high adhesion and lower volume at equal weight compared to SBR, reduced amount of binder can be used in the formulation increasing the amount of active material (to exploit the theoretical capacity and energy density of the battery). In other hands, increased electrode cohesion and adhesion onto current collector ensures required chemical resistance and dimensional stability of electrodes in electrolyte even in stressful conditions. Moreover, chemical affinity of PVDF with commercial polyolefin separators allows to laminate (ensuring better interface) them together. SBR does not provide such advantage, due to lower polarity leading to lack of continuous contact at interface.