Lignin has been demonstrated as the tribopositive nanofillers in boosting the triboelectric performances of biopolymer-based triboelectric nanogenerators (TENGs). However, the complex structures of lignin caused the unclear understanding how the molecular structures of lignin affected the output performances of TENGs. Herein, for the first time, five fractionated lignin with different structures were innovatively employed as the tribopositive nanofillers in CMC. Computational simulations and experimental results verified that the lignin with more S units, A-type linkage and large molecular weight give rise to the higher dielectric constant as well as the triboelectric performances. Relying on this principle, the acetone lignin possessed the highest dielectric behavior and the constructed TENG delivered the maximum V of 204.34 V, I of 6.86 µA, Q of 70.27 nC and instantaneous output power density of 836.64 mW/m under contact frequency of 1 Hz. Moreover, such biofilm can be dissolved in water and the regenerated film delivered stable output performances at least 5 times. Our findings not only provided the in-depth understanding of the relationship between triboelectrification behaviors and molecular structures of lignin, but also boosted the rational designing high-performance lignin-based tribopositive nanofillers for self-powered sensing or mechanical energy harvesting.

中文翻译：

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揭示木质素纳米填料提高摩擦纳米发电机性能的机制

木质素已被证明是摩擦正纳米填料，可以提高基于生物聚合物的摩擦纳米发电机（TENG）的摩擦电性能。然而，木质素的复杂结构导致人们对木质素的分子结构如何影响TENGs的输出性能尚不清楚。在此，首次创新性地采用五种不同结构的分馏木质素作为CMC中的摩擦正性纳米填料。计算模拟和实验结果证实，具有更多S单元、A型键和大分子量的木质素具有更高的介电常数和摩擦电性能。依靠这一原理，丙酮木质素具有最高的介电性能，构建的TENG在1 Hz接触频率下的最大V为204.34 V，I为6.86 µA，Q为70.27 nC，瞬时输出功率密度为836.64 mW/m 。此外，这种生物膜可以溶解在水中，并且再生膜可提供至少5倍的稳定输出性能。我们的研究结果不仅提供了对木质素摩擦起电行为与分子结构之间关系的深入理解，而且促进了用于自供电传感或机械能收集的高性能木质素基摩擦正纳米填料的合理设计。