Ultrathin MXene/Calcium Alginate Aerogel Film for High‐Performance Electromagnetic Interference Shielding

Abstract Ultrathin and high‐performance electromagnetic interference (EMI) shielding materials are urgently demanded for modern microelectronic devices. 2D metal carbides (MXenes) are considered as a promising EMI shielding material due to its metallic conductivity. In this study, sodium alginate is applied as interlayer spacer for Ti 3 C 2 T x nanosheets, which not only prevents the restacking of lamella structure but also serves as building blocks for the sponge‐like structure. Ultrathin Ti 3 C 2 T x /calcium alginate (CA) aerogel films with sponge‐like structure and only tens of microns thickness are prepared through divalent metal ion induced crosslinking, vacuum‐assisted‐filtration induced self‐assembly, and freeze‐drying. Taking advantage of its sponge‐like structure, which facilitates the dissipation of incident electromagnetic waves through multireflection and scattering Ti 3 C 2 T x /CA aerogel film, presents excellent EMI shielding effectiveness (54.3 dB) at a very low thickness of 26 µm. Furthermore, Ti 3 C 2 T x /CA aerogel film shows an outstanding specific EMI shielding efficiency (17586 dB cm 2 g −1 ), which is superior to most reported synthetic materials. The preparation of ultrathin Ti 3 C 2 T x /CA aerogel film provides facile strategy for designing and fabricating high‐performance MXene‐based EMI‐shielding materials, which is highly desirable for various applications including aerospace and smart electronic devices.