Defect Engineering Activates Schottky Heterointerfaces of Graphene/CoSe₂ Composites with Ultrathin and Lightweight Design Strategies to Boost Electromagnetic Wave Absorption

Abstract To tackle the increasingly complex electromagnetic (EM) pollution environment, the application‐oriented electromagnetic wave (EMW) absorption materials with ultra‐thin, light weight and strong tolerance to harsh environment are urgently explored. Although graphene aerogel‐based lightweight EMW absorbers have been developed, thinner thickness and more effective polarization loss strategies are still essential. Based on the theory of EMW transmission, this work innovatively proposes a high attenuation design strategy for obtaining ultra‐thin EMW absorption materials, cobalt selenide (CoSe 2 ) is determined as animportant part of ultra‐thin absorbers. In order to obtain a dielectric parameter range that satisfies the ultra‐thin absorption characteristics and improve the lightweight properties of EMW absorption materials, a composite of CoSe 2 modified N‐doped reduced graphene oxide (N‐RGO/CoSe 2 ) is designed. Meanwhile, the controllable introduction of defect engineering into RGO can activate Schottky heterointerfaces of composites to generate a strong interfacial polarization effect, achieving ultra‐thin characteristics while significantly improving the EM loss capability. In addition, infrared thermal images and anti‐icing experiments show that the composite has good corrosion resistance, infrared stealth, and thermal insulation properties. Therefore, this work provides an effective strategy for obtaining thin‐thickness, light‐weight, and high‐performance EMW absorption materials, embodying the advantages of N‐RGO/CoSe 2 composites in practical applications.