Multifunctional Hollow Carbon Microspheres Enable Superior Electromagnetic Wave Response and Corrosion Barrier

Abstract Electromagnetic (EM) wave absorbing materials with corrosion barrier exhibit immense potential in meeting the requirements of electronic defense technology in the complex marine environments, but still confront conflicts in disentangling the trade‐off of multifunctional applications. Herein, hollow carbon microspheres (HCMs) that simultaneously possess superior EM wave absorption and anti‐corrosion capability have been produced with the aid of self‐sacrificing templates. During the pyrolysis, the reductive characteristic of Zn microspheres and thermal driving force promote magnetic domain evolution, which enables optimized hetero‐interface resonance and strong magnetic interactions, facilitating a minimum reflection loss lower than −40 dB and a wide absorption bandwidth greater than 5 GHz. Furthermore, HCMs‐900 with both anion‐repulsion characteristics and better resistance can partially reduce the adsorption/accumulation of corrosive species and decrease the charge‐carrying ability, and the inevitably generated by‐products of layered double hydroxides with strong anion‐capture ability can hinder the access of corrosive species to the substrate surface, resulting in superior anti‐corrosion capability. This innovative strategy inspires us with a motivated pathway for the rational design of advanced multifunctional anti‐corrosive EM absorbing materials.