Plasma Processing of Electrospun Li-Ion Battery Separators to Improve Electrolyte Uptake

Atmospheric pressure non-equilibrium plasma treatments of poly(vinylidene fluoride) (PVdF) solutions and electrospun Li-ion separators are implemented to improve fiber morphology and increase electrolyte uptake. Plasma pre-treatment of PVdF solutions increased the viscosity and induced a morphological change of polymer chains, enabling the production of defect-free mats with improved mechanical properties compared to those produced from non pre-treated solutions. The post-treatment of the electrospun separator induced a chemical modification of the PVdF surface and an increase of electrolyte uptake. A synergistic effect between the plasma treatments is reported: the electrolyte uptake of the pre&post-treated separators is about 1200%, ten times larger than that of commercial Celgard separators.