取向增强复合锂离子电池隔膜的制备及其性能

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138.0 mA?h/g；纵向拉伸断裂强度为9.2 KPa，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。

Preparation andproperties oforientation reinforced composite separatorfor lithium-ion battery

In order to fabricate the electrospinning Lithium-ion battery separator which possessed excellent mechanical properties in lengthways direction, polyacrylonitrile (PAN) membrane were fabricated atdifferent rotational speeds, concluding that the PAN membrane showed best orientation effect at 700 r/min. Then middle-orientation reinforced PAN membranewhich 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, andits overall properties are superior to isotropous PET/PAN/PET membranes.