Quantitative Defect-Property Correlations in Ti₃C₂T_x MXenes via Precursor-Controlled Defect Engineering

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Chemistry

Background:

• Defect engineering in MXenes is crucial for tuning multifunctional properties.
• Quantitative links between MXene defects and performance are poorly understood due to challenges in controlling defect densities.
• Existing methods lack precise control over defect concentrations in MXenes.

Purpose of the Study:

• To develop a reliable strategy for precisely controlling defect densities in Ti3C2Tx MXenes.
• To establish quantitative correlations between defect structure and multifunctional properties.
• To fabricate MXenes with systematically controlled defects for performance optimization.

Main Methods:

• Controlled synthesis of TiC precursors to adjust carbon stoichiometry.
• Modified Ti3AlC2 MAX phase formation by varying aluminum content.
• Fabrication of Ti3C2Tx MXenes with a range of defect densities.
• Systematic characterization of defect densities and associated material properties.

Main Results:

• Precisely controlled defect densities (vacancies, substitutional defects, lattice strain) in Ti3C2Tx MXenes.
• Established quantitative correlations between defect density and electrical/thermal conductivity, infrared emissivity, electromagnetic shielding, Joule heating, and oxidation stability.
• Achieved defect-minimized Ti3C2Tx MXene with exceptional properties: 26,000 S cm-1 electrical conductivity, 57 W m-1 K-1 thermal conductivity, 90.5 dB shielding effectiveness, 263 °C Joule heating, 0.05 infrared emissivity, and high oxidation resistance.

Conclusions:

• A robust method for controlling MXene defect densities via precursor engineering was demonstrated.
• A quantitative framework linking defect structure to MXene performance and stability was established.
• The findings enable the design of MXenes with tailored properties for advanced applications.