Abstract:

In order to fabricate the electrospinning Lithium-ion battery separator which possessed excellent mechanical properties in lengthways direction, polyacrylonitrile (PAN) membrane were fabricated at different rotational speeds, concluding that the PAN membrane showed best orientation effect at 700 r/min. Then middle-orientation reinforced PAN membrane which was collected at 700 r/min and two layers of disordered polyester (PET) membrane were combined to pripare orientation reinforced compositeseparators.  Meanwhile, isotropous PET/PAN/PET membrane was fabricated at 100 r/min as contrast membrane. The mechanical and electrochemical properties were evaluated. The results show that the electrolyte uptake is 371%, and the thermal shrinkage is 4.1%. The ionic conductivity at room tempertature reaches 0.553 mS/cm and electrochemical stability was 5.27 V. The initial discharge capacity of battery is 138.2 mA?h/g. The breaking strength of the orientation reinforced composite separators is 9.2 MPa in lengthways direction, which is 130% higher than contrast membrane. The mechanical strength of the orientation reinforced composite separator increases observably, and its overall properties are superior to isotropous PET/PAN/PET membranes.

Key words: Iithium-ion baery separator, electrospinning, oriented nanofibrous membrane,  electrochemical property