Ti3C2Tx MXene Sponge Composite as Broadband Terahertz Absorber

Abstract Terahertz (THz) absorption technology is promising in radar stealth, electromagnetic interference (EMI) shielding, and the upcoming 6G communication. However, the most popular metamaterial‐based THz absorbers suffer from complex fabrication process and/or narrowband characteristics. Here, a broadband, lightweight, and hydrophobic THz absorber is realized based on Ti 3 C 2 T x MXene sponge foam (MSF) that is obtained by using a dip‐coating method. Due to the macroscopic impedance matching to free space and various microscopic morphologies of metallic Ti 3 C 2 T x flakes inside porous architecture, the obtained MSF, with only 2 mm thickness, shows almost no THz reflection (minimum ≈ 0.00003%) and high THz absorption over 99.99% under the 100% qualified frequency bandwidth ranging from 0.3 to 1.65 THz. The new strategy of combining large‐pore‐size porous architecture with MXene‐like 2D metallic flakes paves a way to achieving high performance THz absorber with minimal thickness, which is of significance in electromagnetic stealth, shielding, and beyond.