静电纺丝制备锂离子电池用聚氨酯/有机硅复合隔膜

Preparation by Electrospinning Technique and Electrochemical Performance of Polyurethane/Silicone Separators

以聚氨酯与有机硅为原料,采用高压静电纺丝法制备了系列聚氨酯/有机硅复合纤维隔膜,通过傅里叶变换红外光谱及扫描电子显微镜等表征了纤维膜的结构、形貌与力学性能。结果表明,当有机硅加入量为10%时,纤维膜的拉伸强度达到10. 1 MPa,孔隙率为60. 9%,吸液率高达428. 7%,25℃离子电导率达到最佳值4. 5×10-3S/cm。以该隔膜组装成Li Fe PO4/Li电池测试,电流密度为0. 2 C时首次放电容量为152. 8 m A·h/g,1 C循环100次放电容量依旧能保持在135. 2m A·h/g,容量保持率为99. 2%,显示出较好的循环稳定性。

Nanofibrous membranes based on thermoplastic polyurethane（PU） doped with silicone were prepared by an electrospinning technique and the corresponding composite gel polymer electrolytes（GPEs） were obtained after activation in liquid electrolyte. Their morphology characteristics and structure were systematically investigated by scanning electron microscopy（SEM）,Fourier transform infrared spectroscopy（FT-IR）,thermal analysis（TGA）,galvanostatic charge-discharge and electrochemical impedance spectroscopy. The GPE based on PU/DC51-10% shows a high porosity and electrolyte uptake of 60. 9% and 428. 75%,high ionic conductivity of 4. 52 × 10-3 S/cm at 25 ℃,and a first discharge capacity of 152. 8 m A·h/g which is about 99. 2% of the theoretical capacity of Li FePO4. When the PU/DC51-10% film charging and discharging 100 times at 1 C,the film still has stable discharge capacity of 135. 2 m A·h/g. The PU/DC51-10% films present superior electrochemical and mechanical performances,which are very promising for application in polymer lithium ion batteries.