Kirkendall effect-assisted electrospinning porous FeCo/Zn@C nanofibers featuring well-dispersed FeCo nanoparticles for ultra-wide electromagnetic wave absorption

Ultra-wide absorption band and flexibility are needed in multi-scenario applications, however, current electromagnetic wave absorption materials (EMWAMs) are not capable enough to deliver due to rigid structure. Here, we have designed a porous flexible mat composed of Zn-doped carbon (Zn@C) nanofibers (NFs) having encapsulated uniformly dispersed FeCo nanoparticles (NPs) (FeCo/Zn@C) as ultra-wideband absorber. During the electrospinning, the Fe³⁺, Co²⁺ and Zn²⁺ are uniformly immobilized within the NFs nanocrystallization process. Subsequently, the Kirkendall effect is deployed to trigger the generation of FeCo NPs and porous framework under thermal annealing. The FeCo/Zn@C NFs effectively favor magnetic-dielectric synergies due to the coexistence of magnetic FeCo NPs and dielectric carbon components. One-dimensional porous fiber prolongs the attenuation path and enhances multi-scattering and reflection. While the FeCo NPs encapsulated in Zn-doped carbon NFs provide abundant dipole and interfacial polarization. These favorable factors synergistically enhance absorption performance, resulting in a reflection loss value of − 71.58 dB. Moreover, by varying the thickness of absorbers, effective absorption bandwidth spans from 4.26 to 18.00 GHz. Hence, this work offers innovative insights for fabricating advanced EMWAMs.

超宽吸收带和柔韧性在多场景应用中被需要，但目前的电磁波吸收材料由于固有的硬性结构而无法实现。在这里，我们设计了由锌掺杂碳(Zn@C)纳米纤维组成的多孔柔性垫，其封装均匀分散的FeCo纳米颗粒(FeCo/Zn@C)作为超宽带吸收剂。在静电纺丝过程中，Fe³⁺、Co²⁺和Zn²⁺在纳米晶化过程中被均匀固定。随后，在热退火条件下，利用柯肯达尔效应触发FeCo纳米颗粒和多孔骨架的生成。FeCo/Zn@C纳米纤维由于磁性FeCo纳米颗粒和介电特性的碳组分共存而有效地促进了磁-介电协同作用。一维多孔纤维延长了衰减路径，增强了多次散射和反射。包裹在锌掺杂碳纤维中的FeCo纳米颗粒则提供了丰富的偶极子和界面极化。这些有利因素协同提高了电磁波吸收性能，导致反射损耗值为-71.58 dB。此外，通过调节吸收层的厚度，有效吸收带宽在4.26–18.00 GHz之间。因此，这项工作为制造先进的电磁波吸收材料提供了创新的见解。