Ultrastrong and Conductive MXene Films Enabled by Hydrogen and Lonic Bonds

Two-dimensional MXene materials are promising for flexible electronics due to their high conductivity and mechanical strength, yet their films often suffer from poor mechanical robustness and a trade-off between conductivity and mechanical performance. This study introduces a bioinspired "sequential bridging" strategy to fabricate PDA/MXene/SA/Ca²⁺ films (PMSC) via synergistic polydopamine (PDA) surface modification, sodium alginate (SA) hydrogen-bond crosslinking, and Ca²⁺ ionic bridging. The film exhibits exceptional comprehensive properties, achieving a tensile strength of 256.64 MPa, a Young's modulus of 8.06 GPa, and a toughness of 8.39 MJ/m³, which are 7.8, 3.2, and 10.9 times higher than those of pure MXene film, respectively, while retaining a high electrical conductivity of 1700.91 S/cm. Systematic characterization analysis identified multiple enhancement mechanisms, including PDA surface modification, SA induced hydrogen-bond crosslinking, and Ca²⁺ mediated ionic-bond energy dissipation. This multi-crosslinking approach overcomes the limitations of single network strategies, offering a scalable route to high-performance flexible electronics.