Chaobo Liang, Jie He, Yali Zhang, Wei Zhang, Chunlei Liu, Xiangteng Ma, Yaqing Liu* and Junwei Gu*. MOF-derived CoNi@C-silver nanowires/cellulose nanofiber composite papers with excellent thermal management capability for outstanding electromagnetic interference shielding. Composites Science and Technology, 2022, 224: 109445. 2021IF=9.879.（1区材料科学Top期刊）

https://doi.org/10.1016/j.compscitech.2022.109445

Abstract

High-performance electromagnetic interference (EMI) shielding materials with excellent flexibility and superior thermal management properties are ideal candidates for aerospace, communication industry, artificial intelligence, and wearable electronics. Herein, MOF-derived CoNi@C-silver nanowires/cellulose nanofiber (MAg/CNF) composite papers with Janus structure were prepared using a combination of two-step vacuum filtration and hot pressing. The resulting composite papers exhibit distinct electrical differences on both sides. The electrical conductivity of the CoNi@C/CNF side is 8.35×10-12 S/cm, while that of the AgNWs/CNF side is 990 S/cm. EMI shielding effectiveness (SE) of the MAg/CNF composite papers reaches 82 dB in the X-band, benefiting from effective double-layer structure, the AgNWs conductive network and the CoNi@C permeability network for adequate dissipation of electromagnetic waves. Excellent EMI shielding performance is maintained even after being subjected to low temperature of -196℃ and bending cycles of 1000 times. In addition, the MAg/CNF composite paper-based electric heaters exhibit satisfactory heating temperatures at absolutely safe operating voltages for the human as well as sufficient stability and repeatability during repeated heating and cooling cycles. Therefore, our fabricated MAg/CNF composite papers with Janus structure present broad application prospects for high-performance EMI shielding and thermal management in low-temperature environment.

具有出色的柔韧性、卓越的热管理性能的高性能电磁干扰（EMI）屏蔽材料是航空航天、通讯工业、人工智能、可穿戴电子等领域的理想候选。在这项工作中，具有双面结构的CoNi@C-AgNWs/cellulosic nanofiber（MAg/CNF）复合纸被制备采用两步真空抽滤自组装和热压相结合的方法。所得的双层复合纸展现出“一面绝缘、一面导电”特性，CoNi@C/CNF面的电导率低至8.35×10-12 S/cm，而AgNWs/CNF面的电导率高至990 S/cm。MAg/CNF复合纸的EMI屏蔽效能（EMI SE）达到82 dB在X波段，得益于有效的双层结构、AgNWs导电网络和CoNi@C导磁网络对电磁波的充分耗散。即使在经受-196℃的低温和1000次弯曲循环后，复合纸仍可保持卓越的EMI屏蔽性能。此外，MAg/CNF复合纸基电加热器在人体绝对安全的工作电压下表现出令人满意的加热温度以及在长期和重复的加热和冷却循环中具有足够的稳定性和可重复性。因此，具有双面结构的复合纸在低温环境下高性能EMI屏蔽和热管理应用方面具有广阔的应用前景。

本文亮点

1. MAg/CNF复合纸在X波段的EMI SE达到82 dB，并且具有优良的低温和机械稳定性。

2． Janus结构赋予MAg/CNF复合纸一面绝缘（8.35×10-12 S/cm），一面导电（990 S/cm）的独特性质。

3． MAg/CNF复合纸表现出优异的热管理性能，其可以与硅胶垫集成制备具有良好亲肤效果和热疗功能的可穿戴护腕。

第一作者邮箱：lcb@mail.nwpu.edu.cn