Electromagnetic interference (EMI) shielding materials with excellent flexibility

and mechanical properties and outstanding thermal conductivity have

become a hot topic of research in functional composites. In this study, the

“sol–gel‐film conversion technique” is used to assemble polyetherimidefunctionalized

Ti3C2Tx nanosheets (f‐Ti3C2Tx) with poly(p‐phenylene‐2,6‐

benzobisoxazole) (PBO) nanofibers (PNFs), followed by dialysis and vacuum

drying to prepare f‐Ti3C2Tx/PNF films with lamellar structures. When the

loading of f‐Ti3C2Tx is 70 wt%, the f‐Ti3C2Tx/PNF film presents optimal comprehensive

properties, with an EMI shielding effectiveness (SE) of 35 dB and a

specific SE/thickness ((SSE, SE/density)/t) of 8211 dB cm2/g, a tensile strength

of 125.1 MPa, an in‐plane thermal conductivity coefficient (λ) of 5.82 W/(m K),

and electrical conductivity of 1943 S/m. After repeated folding for 10,000 cycles,

the EMI SE and the tensile strength of f‐Ti3C2Tx/PNFs films still remain

33.4 dB and 116.1 MPa, respectively. Additionally, the f‐Ti3C2Tx/PNF film also

shows excellent thermal stability, flame retardancy, and structural stability.

This would provide a novel method for the design and fabrication of multifunctional

composite films and considerably expand the applications of

MXene‐ and PNF‐based composites in the fields of EMI shielding and thermal

management.