The increasing power density of modern electronics has made thermal management a critical challenge. Efficient heat dissipation is essential to maintain device performance, reliability, and longevity. Among emerging materials, MXenes have shown exceptional promise due to their high thermal conductivity, tunable surface chemistry, and compatibility with composite matrices. This article explores their role in heat dissipation, focusing on intrinsic thermal properties, interfacial engineering, and composite integration.
MXenes are a class of two-dimensional transition metal carbides, nitrides, and carbonitrides with the general formula Mn+1XnTx, where M is a transition metal, X is carbon or nitrogen, and Tx represents surface terminations like -O, -F, or -OH. Their layered structure and strong in-plane covalent bonds contribute to high basal-plane thermal conductivity, often exceeding 100 W/mK for select compositions. For instance, Ti3C2Tx, the most studied MXene, exhibits a thermal conductivity range of 25–110 W/mK depending on flake size, defect density, and surface functionalization. The anisotropic nature of MXenes further allows directional heat transport, which can be leveraged in vertically stacked architectures for through-plane dissipation.
Interfacial thermal resistance remains a key bottleneck in MXene-based thermal management. Phonon scattering at MXene-matrix interfaces can significantly reduce effective thermal conductivity in composites. Surface engineering strategies, such as covalent functionalization or polymer grafting, have been employed to improve interfacial adhesion. For example, amine-terminated silanes can react with MXene surface groups, creating stronger bonds with epoxy matrices and reducing interfacial resistance by up to 40%. Another approach involves in-situ polymerization, where monomers infiltrate MXene layers before curing, ensuring uniform dispersion and minimizing voids that impede heat transfer.
Composite design plays a pivotal role in optimizing heat dissipation. Epoxy/MXene composites are widely investigated due to epoxy’s prevalence in electronic packaging. Incorporating 5–10 wt% MXene into epoxy can enhance its thermal conductivity from ~0.2 W/mK to 2–5 W/mK, a tenfold improvement. The percolation threshold—the point at which MXene flakes form a continuous heat transfer network—typically occurs at low loadings (1–3 vol%), making MXenes more efficient than conventional fillers like alumina or boron nitride at comparable concentrations. Hybrid composites, combining MXenes with other high-conductivity materials (e.g., graphene or carbon nanotubes), can achieve synergistic effects. For instance, a ternary epoxy/MXene/graphene composite reached 12.4 W/mK at 15 wt% total filler loading, outperforming either filler alone.
Processing techniques critically influence composite performance. Solution casting is common but may lead to MXene aggregation. To mitigate this, shear-assisted alignment methods, such as blade coating or vacuum filtration, can orient MXene flakes preferentially in-plane, maximizing thermal pathway connectivity. Hot-pressing further densifies the composite, reducing interfacial gaps. For example, hot-pressed Ti3C2Tx/polyvinyl alcohol films achieved 35 W/mK at 50 wt% loading, demonstrating the importance of processing control.
Beyond polymers, MXenes have been integrated into metallic and ceramic matrices for extreme-condition applications. Copper/MXene composites, fabricated via spark plasma sintering, show enhanced thermal conductivity (up to 400 W/mK) while retaining mechanical robustness. In ceramics, MXene additions improve fracture toughness without compromising thermal properties, making them suitable for high-power electronics.
Challenges persist in scalability and stability. MXenes are susceptible to oxidation at elevated temperatures or humid environments, which degrades thermal performance. Encapsulation with impermeable coatings or inert matrix materials can mitigate this. Cost-effective production of large-area MXene films also requires further development to meet industrial demands.
In summary, MXenes offer a versatile platform for advanced thermal management in electronics. Their high intrinsic conductivity, coupled with tailored interfacial engineering and composite design, enables efficient heat dissipation in compact and high-power systems. Continued research into stable, scalable fabrication methods will be crucial for their widespread adoption in next-generation thermal solutions.