For new application of technical lignins as separator material for electric double-layer capacitor (EDLC), we tried first to prepare bipolyester film by melt-polycondensation of polyethylene glycol lignin (PEGL) and maleic anhydride. The EDLC assembled with this film, however, showed lower electrochemical performance than the reference EDLC with commercial cellulosic separator. Porous bipolyester film was then prepared and the resulting EDLC exhibited improved specific capacitance, but high intrinsic and charge transfer resistances. Non-porous terpolyester film was prepared next, using polyethylene glycol 500,000 to improve flexibility of the film, which might lower the resistances. This film was flexible enough and provided the resulting EDLC with superior electrochemical performance to the bipolyester film. EDLC with porous terpolyester film was finally prepared and showed the highest electrochemical performance, comparable to the reference EDLC. Porous morphology and flexibility were key factors to fabricate lignin-based self-standing film as separator material for high-performance EDLC.

中文翻译：

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木质素基三元聚酯薄膜的研制及其在双电层电容器隔板材料中的应用

对于工业木质素作为双电层电容器（EDLC）隔膜材料的新应用，我们首先尝试通过聚乙二醇木质素（PEGL）和马来酸酐的熔融缩聚制备双聚酯薄膜。然而，用这种薄膜组装的 EDLC 的电化学性能低于带有商用纤维素隔膜的参考 EDLC。然后制备多孔双聚酯薄膜，所得 EDLC 表现出改善的比电容，但具有高固有电阻和电荷转移电阻。接下来制备无孔三元聚酯薄膜，使用聚乙二醇 500,000 以提高薄膜的柔韧性，这可能会降低电阻。该薄膜足够柔韧，并为所得 EDLC 提供了比双聚酯薄膜优越的电化学性能。最终制备出具有多孔三元聚酯薄膜的 EDLC 并显示出最高的电化学性能，与参考 EDLC 相当。多孔形态和柔韧性是制造基于木质素的自支撑薄膜作为高性能 EDLC 的隔膜材料的关键因素。