Multi‐dimensional, multi‐interfacial, and multi‐path synergy enables broadband absorption, corrosion resistance, Joule heating, and thermal performances in hierarchical carbon/Ni nanoparticles‐carbon nanocoils foams

Abstract Owing to the severe electromagnetic wave (EMW) pollution and the increasingly intricate operating environments, an excellent EMW absorber with multiple functions has become imperative. Nevertheless, achieving the seamless co‐existence of disparate functional features in deliberately engineered EMW absorbers remains a formidable challenge. Herein, 3D/0D–1D hierarchical carbon/Ni nanoparticles‐carbon noncoils (CNCs) composite foams can be precisely synthesized through a simple freeze‐drying process, carbonization treatment, and chemical vapor deposition process successively. The outcomes reveal that incorporating 1D CNCs into 3D/0D carbon/Ni nanoparticles composite foams successfully constructs multi‐dimensional, multi‐interfacial and multi‐path structures. This significantly improves the impedance matching characteristics of 3D/0D–1D hierarchical carbon/Ni nanoparticles‐CNCs composite foams and enhances their polarization loss and conduction loss capabilities. Consequently, the complementarity in structure and composition endows the 3D/0D–1D hierarchical carbon/Ni nanoparticles‐CNCs composite foams with outstanding EMW absorption properties with a minimum reflection loss value of −52.91 dB and a broad effective absorption bandwidth of 6.0 GHz. Moreover, this synergistic effect equips 3D/0D–1D hierarchical carbon/Ni nanoparticles‐CNCs composite foams with remarkable radar stealth capabilities, outstanding corrosion resistance, excellent Joule heating performance, and exceptional thermal insulation. This makes them highly promising for applications in complex and variable environments. image