Heating Effect on Physical and Electrochemical Properties of Nanofibrous Polyacrylonitrile Separator for Lithium Batteries

Nanofibrous polyacrylonitrile (PAN) membranes as nonwoven separators were prepared by electrospinning followed by a thermal treatment to improve their physical properties. The effect of the thermal treatment on the physical and electrochemical properties of the PAN separators was investigated. With increasing heating time, the PAN nanofiber separators became denser with decreasing size of fully interconnected pores. The tensile strength and modulus of the nanofibrous PAN separators varied with the heating temperature and heating time. The maximum tensile strength and modulus were obtained at a heating temperature and heating time of 170 degrees C and 5 h, respectively. The cell assembled with the PAN separator prepared at 170 degrees C for 5 h exhibited high capacity retention and stable cycle performance, even at higher discharge current densities.