Effect of thermal processing conditions on the structure and properties of porous PENK/PVDF composite films and its application as lithium-ions separators

Abstract

By developing high-performance lithium-ion battery technology, the demands on the design of separator modification have increased. However, battery performance and safety are limited by conventional polyolefin separators' poor thermal resistance and electrolyte wettability. Biphenyl-type poly (arylene ether nitrile ketone) (BP-PENK) is synthesized. PENK polymers are a class of poly (aryl ether) with excellent properties of both Poly (aryl ether nitrile) (PEN) and Poly (ether ketone) (PEEK). The BP-PENK/PVDF composite film is further processed by non-solvent induced phase separation (NIPS), and the impact of annealing temperatures on the thermal resistance and crystalline phase structure of composite separators has been studied. The composite separator owns enhanced ionic conductivity, excellent electrolyte wettability, and superior thermal durability. The cell equipped with the composite separator has a discharge-specific capacity of 146.5 mAh·g−1 and a capacity retention rate of 86.64 %. In this way, A novel approach to producing lithium-ion battery separators that possess outstanding electrochemical properties and high thermal durability is provided.