Speaker
Description
Two-dimensional (2D) transition metal carbides and/or nitrides, referred to as MXenes, have recently gained considerable attention due to their unique combination of properties, such as excellent electrical conductivity and high electrochemical capacitance. However, translating these nanoscale properties into bulk or macroscopic structures remains a challenge, as both pure and composite MXene assemblies often suffer from performance trade-offs. For instance, while pure Ti₃C₂Tₓ MXene can yield films and fibers with outstanding conductivity (>10,000 S cm⁻¹), their tensile strength remains relatively low (i.e., around 34 MPa for films and 40 MPa for fibers). To overcome this drawback, we explored the use of bridging additives (e.g., polydopamine [1], nanocellulose [2], and silk nanofibrils [3]) between MXene layers to replicate the hierarchical architecture of natural materials like nacre. This strategy referred to as “sequential bridging” (SB), enhances the mechanical robustness of free-standing MXene films and fibers while preserving electrical and electrochemical performance. For example, fibers fabricated using this approach demonstrate tensile strengths >200 MPa, conductivities >8000 S cm⁻¹, and volumetric capacitances >900 F cm⁻³ [4]. In addition, we emphasized the role of preserving sheet alignment, tracked using Wide-Angle X-ray Scattering (WAXS), in ensuring uniform electrical contact and enabling rapid ion transport. Methods for controlling alignment, such as shear-induced orientation during processing or the application of tensile forces after fabrication, were also discussed. These findings offer valuable insights for developing durable and multifunctional MXene-based materials tailored to specific applications. This technique may be extended to other 2D nanomaterials, fostering their broader implementation in next-generation technologies.
References
[1] - K.A.S. Usman, J. Zhang, D.Y. Hegh, A.O. Rashed, D. Jiang, P.A. Lynch, P. Mota‐Santiago, K.L. Jarvis, S. Qin, E.L. Prime, and M. Naebe, L.C. Henderson and J.M. Razal, Advanced Materials Interfaces, 8(7), 2002043 (2021)
[2] - K.A.S. Usman, C.J.O. Bacal, J. Zhang, S. Qin, P.A. Lynch, P. Mota‐Santiago, M. Naebe, L.C. Henderson, D.Y. Hegh, and J.M. Razal, Macromolecular Rapid Communications, 43(11), 2200114 (2022)
[3] - K.A.S. Usman, Y. Yao, C.J.O. Bacal, J. Zhang, K.L. Jarvis, P.A. Lynch, P. Mota‐Santiago, S. Qin, M. Naebe, L.C. Henderson, and D.Y. Hegh, and J.M. Razal, Advanced Materials Interfaces, 10(9), 2201634 (2023)
[4] - K.A.S. Usman, J. Zhang, C.J.O. Bacal, S. Qin, P. Mota-Santiago, P.A. Lynch, M. Naebe, L.C. Henderson, D. Hegh, and J.M. Razal, 2D Materials, 9(4), 044003 (2022)
