MXene‐Based Ultrathin Electromagnetic Wave Absorber with Hydrophobicity, Anticorrosion, and Quantitively Classified Electrical Losses by Intercalation Growth Nucleation Engineering

Abstract MXene, a highly regarded material, has garnered significant attention within the electromagnetic wave (EMW) absorption field. However, the practical application of MXene is limited in harsh environments. Herein, a magic technique strategy of intercalation growth nucleation engineering is employed to prepare multifunctional MXene‐based EMW absorption materials. By regularly introducing different metal ions between the layers of MXene, an ultrathin absorber can be achieved by annealing after reacting in specific positions. The synthesized MCFC‐69‐8 shows hydrophobicity properties and exhibits a large charge‐transfer resistance of 18112 Ω cm 2 with a low corrosion rate and corrosion rate, indicating a good anti‐corrosion property. Through applying a series of mathematical methods, MCFC‐69‐8 shows 25% relaxation polarization loss and 75% conduction loss, and its relaxation time is linked with the specific type of relaxation polarization loss, resulting in an effective absorption bandwidth (EAB) of 4.9 GHz with an ultra‐thin optimal matching thickness of 1.48 mm. Finally, an absorber is built using CST to attain an ultrabroad EAB covering 2–18 GHz. This engineering not only simplifies the intercalation process but also achieves a high‐performance and anti‐corrosion EMW absorber, providing a valuable perception for realizing thinner MXene‐based EMW absorbers in the future.