A facile route for the fabrication of polypropylene separators for lithium ion batteries with high elongation and strong puncture resistance

A facile route for fabrication of polypropylene separators for lithium ion batteries with high elongation and strong puncture resistance has been proposed in this work. Polypropylene separators immersing in paraffin wax have been prepared to introduce small molecules into separators. The influence of small molecules on mechanical properties of separators are studied in this work. The elongation at break stretched in transverse direction of separators significantly increases for more than 300% while puncture depth and force raise 50% after treatment with paraffin wax for two hours. Meanwhile, no clear change of pore structure can be seen after treatment. The behind mechanism has been discussed as well. Moreover, comprehensive performance of batteries equipped with modified separators has been evaluated. The modified separators exhibit same electrochemical performances compared to original separators. Generally, paraffin modification is a facile and effective route for mechanical enhancement of separators w...