Preparation and performance of polyacrylonitrile-based nanofiber separator on surface of graphite electrode

Abstract

In order to make full use of the porous structure and overcome the shortcoming of low mechanical strength of nanofiber-based separators, polyacrylonitrile (PAN) separator was prepared directly on the surface of graphite anode by the electrospinning method. And an integrated separator/anode assembly (SAA) was formed. The microstructure, mechanical strength, electrolyte wettability, thermal resistance and battery performance were systematically investigated. The results show that the nanofibers in PAN separator are tightly bonded to the rough surface of graphite anode, resulting in a well-integrated interface structure (tensile strength higher than 200 MPa). Compared with polyolefin separators, SAA exhibits better electrolyte affinity and higher ion conductivity (1.9 mS/cm). The above advantages endow the LiCoO2/SAA full cell with better C-rate (capacity retention 44.3% at 32 C compared with that at 0.5 C) and cycling performances (capacity retention 98% after 200 cycles at 0.2 C) compared with those of 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.

Keywords

• lithium-ion battery
• nanofiber separator
• integrated assembly
• interface compatibility
• mechanical property
• charge-discharge performance