取向增强复合锂离子电池隔膜的制备及其性能

Preparation and properties of orientation reinforced composite separator for lithium-ion battery

为获得纵向拉伸性能优异的静电纺丝锂离子电池隔膜,首先在不同转速条件下制备聚丙烯腈(PAN)纤维膜,分析得出在700 r/min时,PAN纤维排列取向性最好。然后将在700 r/min条件下制备得到的PAN增强层纤维膜作为中间层,结合上下2层杂乱分布的聚酯(PET)纤维膜形成取向增强复合隔膜,在低速(100 r/min)条件下制备了PET/PAN/PET各向同性纤维膜作为对比膜。表征了2种隔膜的物理力学性能及电化学性能。结果表明:取向增强复合隔膜的吸液率为371%,热收缩率为4.1%,室温下离子电导率为0.553 mS/cm,电化学稳定窗口为5.27 V;由其制备的电池首次放电比容量为138.2 mA·h/g;纵向拉伸断裂强度为9.2 MPa,比对比膜提高了130%,该取向增强复合隔膜机械强度显著提高,综合性能优于PET/PAN/PET各向同性纤维膜。

In order to fabricate the electrospinning lithium-ion battery separator which possessed excellent mechanical properties in lengthways direction,polyacrylonitrile（ PAN） membranes 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 prepare orientation reinforced composite separators. 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 temperature reaches 0. 553 mS/cm and the electrochemical stability is 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.