聚乙烯-乙烯醇磺酸锂/聚偏氟乙烯-六氟丙烯锂离子电池隔膜的制备及性能

《复合材料学报》优先在线发表论文。

摘  要：以聚乙烯-乙烯醇的磺化物(EVOH-SO3Li)和聚偏氟乙烯-六氟丙烯(PVDF-HFP)为原料，利用高压静电纺丝技术纺制成高孔隙率、纤维粗细均匀的EVOH-SO3Li/PVDF-HFP复合隔膜材料。利用FTIR、SEM、万能拉伸试验仪、TGA、BMP3电化学工作站和电池检测系统对隔膜进行测试分析。测试结果表明：EVOH-SO3Li/PVDF-HFP隔膜形成致密的三维网络结构，纤维粗细均匀，孔径均一，EVOH-SO3Li/PVDF-HFP隔膜的孔隙率和吸液率分别为85%和437%；与纯EVOH-SO3Li隔膜相比，复合隔膜的拉伸强度最大值从2.17 MPa提高至8.33 MPa，起始热分解温度升高至310℃，并表现出良好的电化学性能和电池性能。其中电化学稳定窗口由5.6 V增至5.8 V，界面阻抗由425.51 Ω降低至115.24 Ω，离子电导率由1.592×10-3 S/cm提高至3.102×10-3 S/cm；采用EVOH-SO3Li/PVDF-HFP隔膜组装的锂离子电池在0.5 C放电电流下循环100次后容量保持率为96.65%。

关键词：锂离子电池隔膜；聚偏氟乙烯-六氟丙烯；EVOH-SO3Li；高压静电纺丝；电化学性能

Abstract: High-porosity, uniform-thickness composite separator was prepared by high-pressure electrospinning using polyethylene-vinyl alcohol sulfonate (EVOH-SO3Li) and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) as raw materials. The performance of the separator was characterized by FTIR, SEM, universal tensile tester, TGA, BMP3 electrochemical workstation and battery testing system. The test results show that the EVOH-SO3Li/PVDF-HFP separator forms a dense three-dimensional network structure with uniform fiber thickness and uniform pore size. The porosity and liquid absorption rate of EVOH-SO3Li/PVDF-HFP separator are 85% and 437%, respectively; Compared with pure EVOH-SO3Li separator, the maximum tensile strength of EVOH-SO3Li/PVDF-HFP composite separator is increased from 2.17 MPa to 8.33 MPa. The initial thermal decomposition temperature is also raised to 310 ℃. The excellent performance of electrochemical and battery is exhibited. The electrochemical stability window is increased from 5.6 V to 5.8 V, and the interfacial impedance is reduced from 425.51 Ω to 115.24 Ω, and the ionic conductivity is increased from 1.592×10-3 S/cm to 3.102×10-3 S/cm; Lithium-ion batteries assembled with EVOH-SO3Li/PVDF-HFP separators have a capacity retention rate of 96.65% after 100 cycles at 0.5 C discharge current.

Keywords: lithium-ion battery separator; poly(vinylidene fluoride-hexafluoropropylene); polyethylene-SO3Li; electrospinning; electrochemical property

作者：巩桂芬等，哈尔滨理工大学 材料科学与工程学院，哈尔滨

通讯作者：巩桂芬，哈尔滨理工大学 材料科学与工程学院，哈尔滨

全文详见中国知网学术期刊优先数字出版。