Metal-Bonded Atomic Layers of Transition Metal Carbides (MXenes)

Although 2D transition metal carbides and nitrides (MXenes) have fantastic physical and chemical properties as well as wide applications, it remains challenging to produce stable MXenes due to their rapid structural degradation. Here, unique metal-bonded atomic layers of transition metal carbides with high stabilities are produced via a simple topological reaction between chlorine-terminated MXenes and selected metals, where the metals enable them to not only remove partially Cl terminations, but also bond with adjacent atomic MXene slabs, driven by the symmetry of MAX phases. The films constructed from Al-bonded Ti₃C₂Cl_x atomic layers show high oxidation resistance up to 400 °C and low sheet resistance of 9.3 Ω sq⁻¹. Coupled to the multilayer structure, the Al-bonded Ti₃C₂Cl_x film displays a significantly improved electromagnetic interference (EMI) shielding capability with a total shielding effectiveness value of 39 dB at a low thickness of 3.1 µm, outperforming pure Ti₃C₂Cl_x film.