Anisotropic semi-aligned PAN@PVdF-HFP separator for Li-ion batteries.

Compared with the common electrospun nanofibers, the alignment of the nanofibers exhibits interesting anisotropic mechanical properties and structural stability. In this paper, semi-aligned PAN@PVdF-HFP nanofiber separators were prepared by a modified electrospinning method. The composite separators exhibit anisotropic mechanical properties and enhanced electrochemical performance compared with electrospun PAN films. The PAN@PVdF-HFP nanofiber separator can deliver an ionic conductivity of 1.2 mSccm-1 with electrochemical stability up to 5.0 V. The LiFePO4/Li cell with semi-aligned PAN@PVdF-HFP separator shows excellent cycling performance, good rate capability, as well as high discharge capacity.