Mechanically robust and multifunctional Ti3C2Tx MXene composite aerogel for broadband EMI shielding

Because of its high electrical conductivity and low density, Ti3C2Tx MXene aerogel is thought to be a promising electromagnetic interference (EMI) shielding material. However, it is suffering from high reflection shielding and poor mechanical strength, which naturally hinders its practical application. Herein, we constructed PDMS-encapsulated Fe3O4/multi-walled carbon nanotubes (MWCNTs)/Ti3C2Tx MXene aerogel by combining the bi-directional freeze-drying technique with vacuum impregnation. The lamellar porous architecture and rational components endow the PDMS-encapsulated composite aerogel with superior EMI shielding properties in the X- and Ku-bands. Specifically, the optimal total shielding effectiveness (SET) of the PDMS-encapsulated composite aerogel (3 mm) could reach 43.6 dB, whereas the corresponding reflection shielding effectiveness (SER) is only 7 dB (approximately 16.7 % of SET). The shielding mechanism was also comprehensively disclosed. Simultaneously, contributed by the synergistic effect of lamellar porous structure and PDMS, the PDMS-encapsulated composite aerogel possesses satisfactory compressive strength (28.62 MPa) and tensile strength (1.67 MPa). Additionally, the PDMS-encapsulated composite aerogel also exhibits promising applications in thermal insulation.