Porous PAN micro/nanofiber membranes with potential application as Lithium-ion battery separators: physical, morphological and thermal properties

The porous PAN micro/nanofiber membranes with an average diameter of 700–800 nm were produced in one step by electrospinning a ternary system of PAN/DMF/H₂O with phase separation mechanism. Also, non-porous PAN micro/nanofiber membranes with a similar diameter were prepared. Physical, morphological, mechanical and thermal properties of the porous PAN micro/nanofiber membranes were characterized and compared with those of non-porous PAN membranes. Thermal shrinkage of the porous PAN micro/nanofiber membranes and the Celgard PP separators were examined to be 15% and 95%, respectively, after treating for 45 min at 200 °C. The porosity impacts of porous PAN micro/nanofiber membranes were explored on some of the effective properties in battery performance. The results revealed that the porous PAN micro/nanofiber membranes had a higher air permeability value than the Celgard PP separators, indicating that the porosity, interconnected pores and ionic conductivity were higher. The porous PAN micro/nanofiber membranes had an enhanced electrolyte wettability, small contact angle and large electrolyte uptake leading to be the most promising candidate for Li-ion battery (LIB) separators.