Bridging sheet size controls densification of MXene films for robust electromagnetic interference shielding

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• MXene films suffer from low ambient stability and poor conductivity due to structural voids, limiting their application in electromagnetic interference (EMI) shielding.
• Developing compact MXene films is crucial for improving their electronic properties and durability.

Purpose of the Study:

• To develop a densification process for MXene films using graphene oxide (GO) as a bridging agent.
• To investigate the effect of GO sheet size on MXene film compactness and performance.
• To establish the structure-activity relationship for enhanced EMI shielding and stability in MXene-based materials.

Main Methods:

• Controlled densification of MXene films by incorporating graphene oxide (GO) with tailored sheet sizes.
• Characterization of the structural compactness and electron transport pathways in MXene-GO films.
• Evaluation of electrical conductivity and electromagnetic interference (EMI) shielding performance.
• Assessment of ambient stability over time.

Main Results:

• A negative correlation between GO sheet size and film densification was identified, enabling the preparation of highly compact MXene-GO films.
• The conductivity of the densified MXene-GO film increased by 1.7 times (∼1.6 × 10^5 S/m) compared to pure MXene films.
• Record-breaking EMI shielding performance (5.2 × 10^6 dB/m) was achieved for 10 μm-thick MXene-GO films.
• The compact structure significantly improved ambient stability, retaining 88.7% conductivity and 90.0% EMI shielding after 15 days.

Conclusions:

• Tailoring graphene oxide sheet size is an effective strategy for controlling the densification and improving the performance of MXene films.
• The densified MXene-GO films exhibit superior electrical conductivity, EMI shielding, and ambient stability, making them promising for flexible electronics.
• This work highlights the importance of structural engineering in optimizing MXene-based materials for demanding applications.