Preparation of polystyrene-grafted poly(vinylidene fluoride) membranes for lithium secondary batteries

Polystyrene-grafted poly(vinylidene fluoride) (PVDF-g-PS) membranes were prepared by simultaneous γ-irradiation-induced graft polymerization. The morphological changes of the prepared membranes were investigated by scanning electron microscopy. The degree of grafting (DOG) increased with increasing absorption doses. The degree of crystallinity upon grafting was found to decrease due to the formation of amorphous polystyrene layer. The grafted membranes showed better electrolyte uptake and retention ability compared to the ungrafted membrane. The ionic conductivity of the membrane with LiClO4/γ-butyrolactone-based electrolyte increased with the increase in the DOG and reached 2.50 mS/cm for the highest sample.