Wrinkled Titanium Carbide (MXene) with Surface Charge Polarizations through Chemical Etching for Superior Electromagnetic Interference Shielding

Abstract Despite the fact that the high conductivity of two‐dimensional laminated transition metal carbides/nitrides (MXenes) contributes to the outstanding electromagnetic interference (EMI) shielding by the reflection of electromagnetic waves (EWs), it is difficulty to improve EMI shielding by pursuing higher conductivity due to the limitation of intrinsic properties. Here, we achieve superior EMI shielding by introducing the absorption of EWs in MXenes with micro‐sized wrinkles which are induced by abundant Ti vacancies under chemical etching. The shielding effectiveness is up to 107 dB at a thickness of 20 μm. Combining with atomic‐scale structure observation and the first‐principles calculations, it is concluded that the promotion of EMI shielding originates from the resonant absorption of formed electric dipoles induced by the asymmetrical distribution of charge densities near Ti vacancies. Our results could open a new vista for developing two‐dimensional EMI shielding materials.