An integrated separator/anode assembly based on electrospinning technique for advanced lithium-ion batteries

Abstract In this work, polyacrylonitrile (PAN) nanofiber separator is fabricated directly on the surface of the graphite anode of lithium-ion batteries, resulting in an integrated separator/anode assembly (S A A). On one hand, the porous structure and polar surface of PAN nanofiber separator enable the S A A with superior electrolyte affinity and wettability. On the other hand, the interlocking structure at the interface between graphite anode and nanofiber separator enhances the mechanical and thermal stabilities of the separator as well as the interface compatibility. As a result, the S A A possesses an electrolyte contact angle of about 0 o and a thermal shrinkage of less than 2% at 150 °C for 0.5 h, resulting from the coupling effect between nanofiber separator and graphite anode. The above advantages endow the LiCoO2/S A A full cell with better C-rate (capacity retention 44.3% at 32.0 C compared with that at 0.5 C) and cycling performances (capacity retention 98.0% after 200 cycles at 0.2 C) as well as higher thermal resistance compared with those of the common LiCoO2/polyolefin separator/graphite battery. Consequently, this work provides an advanced separator/anode assembly and the corresponding fabrication method, which may be a new strategy for improving the charge-discharge performance and assembly efficiency of lithium-ion batteries.