Mineralized Collagen‐Inspired Strong and Stiff MXene Fibers Enabled by Multiscale Interfacial Reconstruction

ABSTRACT Ti 3 C 2 T x MXene nanosheets are promising building blocks for load‐bearing functional fibers because of their high electrical conductivity, favorable mechanical properties, and abundant surface terminations. However, discontinuous, weakly coupled intersheet contacts hinder translating these nanosheet‐level advantages into macroscopic fibers. Inspired by the cooperative load‐bearing architecture of mineralized collagen, a multiscale interfacial reconstruction strategy is developed for continuously wet‐spun MXene fibers. Through Zn 2+ ‐mediated assembly and drawing, large and small MXene sheets and bacterial cellulose (BC) nanofibers are cooperatively organized into coupled homogeneous and heterogeneous interfaces, converting weak, discontinuous contacts into a stable load‐transfer architecture. Small MXene sheets form distributed connections, while BC nanofibers provide sustained constraints, dispersing stress across multiple contact regions and limiting sheet displacement during deformation. The resulting fibers achieve a Young's modulus of 54.2 GPa and a tensile strength of 506.3 MPa—ranking among the top‐performing combinations of stiffness and strength reported for MXene‐based fibers. The fibers also combine high conductivity (2827.7 S cm −1 ), a thickness‐normalized electromagnetic interference shielding effectiveness of 435 dB mm −1 , good stability under humid conditions, and a gauge factor of 140.7 for low‐strain sensing. This work provides a scalable interface strategy for achieving stable load transfer and high multifunctional performance in 2D nanosheet assemblies.