Multi-Scale Synergistic Regulation Strategy to Develop Mesoporous Carbon Hollow Nanospheres/Bean-Shaped Nanofibers for Corrosion-Resistant, Flexible, and Lightweight Microwave Absorbers

TL;DR

This paper introduces a new strategy to create lightweight, flexible, and corrosion-resistant microwave absorbers using a multi-scale design of carbon nanomaterials.

Contribution

A novel 'micro-meso-macro' multi-scale regulation strategy for fabricating core@shell carbon nanocomposites with enhanced microwave absorption.

Findings

The optimized nanocomposites achieved a minimum reflection loss of −61.03 dB at 2.42 mm.

The material showed an effective absorption bandwidth of 6.2 GHz at 2.18 mm.

The nanocomposites exhibited excellent corrosion resistance, hydrophobicity, flexibility, and lightweight properties.

Abstract

Addressing the critical demand for next-generation lightweight, high-efficiency microwave absorbers, this paper proposes a “micro-meso-macro” multi-scale synergistic regulation strategy. Specifically, core@shell mesoporous carbon hollow nanospheres (HNSs)@carbon bean-shaped nanofibers (BNFs) are designed and fabricated efficiently using SiO2/carbon solid nanospheres as precursor through a continuous electrostatic spinning, heat treatment, carbonization, and hydrofluoric (HF) etching. The acquired results suggest that the regulation of carbonization temperature greatly improves the graphitized degree of mesoporous carbon HNSs@carbon BNFs, which significantly enhances the values of complex permittivity. Furthermore, the introduction of a controllable number of mesoporous carbon HNSs at the mesoscale significantly increases the specific surface area and promotes the interfacial polarization effects. The macroscopic 3-dimensional continuous conductive network constructed via electrospinning further enhances electron transport capability and conductive loss efficiency. Benefiting from the excellent collaborative design between multi-scale structure and composition, the optimized mesoporous carbon HNSs@carbon BNFs display excellent microwave absorption properties with a minimum reflection loss (RLmin) of −61.03 dB at 2.42 mm and an effective absorption bandwidth (EAB) of 6.2 GHz at 2.18 mm. Meanwhile, the acquired mesoporous carbon HNSs@carbon BNFs also present excellent corrosion resistance, hydrophobicity, flexibility, and lightweightness. Generally, the finding proposes a simple route for the production of novel core@shell C@C nanocomposites, which makes the best of multi-scale construction strategy to develop lightweight multifunctional microwave absorbers.

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