Wu Xiaohan, Hong Guo, Zhang Xuetong
Suzhou Institute of Nano-Tech and Nano-Bionics , Chinese Academy of Sciences , Suzhou 215123 , China.
University of Chinese Academy of Sciences , Beijing 10000 , China.
Langmuir. 2019 Mar 12;35(10):3814-3821. doi: 10.1021/acs.langmuir.8b04007. Epub 2019 Feb 27.
Graphene aerogel fibers (GAFs) with low density, high specific surface area, and high porosity can be used as the host material to incorporate another component and thus form multifunctional fibers, which have potential applications in wearable devices, thermoregulating apparatus, sensors, and so forth. However, the intrinsically low electric conductivity of GAFs hampers them in the fields of electrothermal heating and electromagnetic interference (EMI) shielding. Herein, we report a new aerogel fiber composed by graphene sheets and nickel nanoparticles with low density (55-192 mg/cm), high electric conductivity (0.8 × 10 to 4.5 × 10 S/m), and high specific surface area (49-105 m/g). The graphene/Ni aerogel fibers (GNAFs) were synthesized initially from reduced graphene oxide hydrogel fibers followed by an electroless plating process. Further investigations have demonstrated that the resulting GNAFs possess excellent electrothermal property, faster electrothermal response, high mechanical and electrical stability as the electric wire, and excellent EMI shielding performance as the composite filler. The saturated temperature of GNAFs can reach 174 °C with an applied voltage of only 5 V, and the heating rate surpasses those of commercial Kanthal and Nichrome wires about 2.1 times and 2.6 times, respectively. The EMI shielding effectiveness of GNAFs is higher than 30 dB at the long bandwidth of 12.5-20 GHz. Specifically, it can shield more than 99.99% of the incident wave at the bandwidth of 15-20 GHz.
具有低密度、高比表面积和高孔隙率的石墨烯气凝胶纤维（GAFs）可作为主体材料掺入其他成分，从而形成多功能纤维，在可穿戴设备、温度调节装置、传感器等领域具有潜在应用。然而，GAFs固有的低电导率限制了它们在电热加热和电磁干扰（EMI）屏蔽领域的应用。在此，我们报道了一种由石墨烯片和镍纳米颗粒组成的新型气凝胶纤维，其具有低密度（55 - 192 mg/cm）、高电导率（0.8×10至4.5×10 S/m）和高比表面积（49 - 105 m²/g）。石墨烯/镍气凝胶纤维（GNAFs）最初由还原氧化石墨烯水凝胶纤维合成，随后进行化学镀工艺。进一步研究表明，所得的GNAFs具有优异的电热性能、更快的电热响应、作为电线的高机械和电气稳定性以及作为复合填料的优异EMI屏蔽性能。GNAFs在仅施加5 V电压时饱和温度可达到174°C，加热速率分别超过商用康泰尔丝和镍铬丝约2.1倍和2.6倍。GNAFs在12.5 - 20 GHz的宽频带上EMI屏蔽效能高于30 dB。具体而言，在15 - 20 GHz带宽下，它可以屏蔽超过99.99%的入射波。
