共纺聚乙烯-乙烯醇锂-热塑性聚氨酯锂离子电池隔膜热力学及电化学性能

为了改善锂离子电池隔膜的热力学和电化学等性能,以聚乙烯-乙烯醇锂(EVOH-Li)和热塑性聚氨酯(TPU)为原料,利用高压静电纺丝法进行双针头同时纺丝,制备了两种不同纤维丝相互缠结的EVOH-LiTPU共纺膜。其中,EVOH-Li具有自由脱嵌的锂离子,可以增加电池隔膜的离子导电性;TPU具有良好的力学性能和韧性,可以增加锂离子电池隔膜的抗穿刺性,从而提高其安全性。研究了EVOH-Li-TPU共纺膜的微观形貌、力学性能、吸液率、孔隙率、热学性能及电化学性能,并与EVOH-Li和TPU单纺膜的相关性能进行对比。结果表明,EVOH-Li-TPU共纺膜的拉伸强度和断裂伸长率分别达到6.09 MPa和79.26%,孔隙率和吸液率分别达到84%和321%,室温离子电导率为4.41×10^–4 S/cm,界面阻抗相比EVOH-Li和TPU单纺膜显著降低,电化学窗口为5.0 V,EVOH-Li-TPU共纺膜相比于EVOH-Li和TPU单纺膜,各种性能均有所增强。

Thermodynamic and electrochemical properties of co-spun polyvinyl-vinyl alcohol lithium-thermoplastic polyurethane lithium ion battery separator

In order to improve the thermodynamic and electrochemical properties of lithium ion battery separators,polyvinyl-vinyl alcohol lithium(EVOH-Li) and thermoplastic polyurethane(TPU) were used as the raw materials.High voltage electrospinning was used to spin two needles simultaneously. The EVOH-Li-TPU co-spinning separators for lithium ion batteries were prepared. The EVOH-Li has free de-intercalation lithium ions. The ionic conductivity of battery separator is increased. The TPU has good mechanical properties and toughness. The puncture resistance of lithium ion battery separator is increased, and its security is improved. The morphology,mechanical properties, liquid absorption, porosity, thermal properties and electrochemical properties of the EVOH-Li-TPU co-spinning separators were studied, and compared with EVOH-Li and TPU mono-spun membranes. The results show that the tensile strength and elongation at break of the EVOH-Li-TPU co-spinning separator reach to 6.09 MPa and 79.26%, the porosity and liquid absorption reach to 84% and 321%, the ionic conductivity at room temperature is 4.41×10^-4 S/cm, the interfacial impedance is reduced compared with the EVOH-Li and TPU mono-spun membranes, and the electrochemical window is 5.0 V. Comparing with EVOH-Li and TPU single spinning, the properties of EVOH-Li-TPU co-spinning separators is improved.