Preparation of PAN/PI Composite Nanofiber Separator by Electrospinning and Its Application in Lithium-Sulfur Batteries

与商用聚烯烃类膜相比，静电纺丝聚丙烯腈(PAN)膜有更高的孔隙率、电解质吸收率、热稳定性和离子电导率。然而较差的机械性能和阻硫能力限制了静电纺丝PAN膜在锂硫电池中的实际应用。本研究通过静电纺丝制备了PAN/聚酰亚胺(PI)复合纳米纤维隔膜，以改善其机械性能和电化学性能。结果表明，复合膜具有优异的热稳定性，并且表现出比纯PAN膜更好的机械性能(拉伸强度提高了1.8倍)，同时还能有效抑制多硫化物的穿梭。PI的加入可以明显提高孔隙率和电解质吸收率。此外，复合膜具有高离子电导率(1.31 × 10−3 S/cm)、宽电化学窗口(4.7 V)和优异的循环性能。在0.1 C下循环100圈后，它仍能保持594.38 mAh/g的放电比容量。静电纺丝PAN/PI膜可能成为锂硫电池隔膜有潜力的候选者。Electrospinning polyacrylonitrile (PAN) separators have higher porosity, electrolyte uptake, thermal stability, and ionic conductivity than commercial polyolefin-based separators. However, the poor mechanical properties and sulfur-blocking ability limit the practical application of electrospinning PAN separators in lithium-sulfur batteries. In this study, PAN/polyimide (PI) composite nanofiber separators were prepared by electrospinning to improve their mechanical and electrochemical properties. The results show that the composite separator has excellent thermal stability and exhibits better mechanical properties than the pure PAN separator (1.8-fold increase in tensile strength), as well as effective inhibition of polysulfide shuttling. The incorporation of PI significantly improves the porosity and electrolyte uptake. In addition, the composite separator has a high ionic conductivity (1.31 × 10−3 S/cm), a wide electrochemical window (4.7 V) and excellent cycling performance. It maintains a discharge specific capacity of 594.38 mAh/g after cycling 100 cycles at 0.1 C. The electrospinning PAN/PI separator may be a promising candidate for lithium-sulfur battery separators.