ScholarWorks@성균관대학교

초록

Defect engineering holds great promise for tailoring the multifunctional properties of MXenes. However, quantitative correlations between defect and material performance remain largely unexplored due to the lack of a reliable strategy to precisely control defect densities. Here, we demonstrate that the defect density of Ti3C2Tx MXenes-including titanium and carbon vacancies, substitutional oxygen defects, and the associated lattice strain-is precisely controlled by adjusting carbon stoichiometry during TiC precursor synthesis and aluminum content during Ti3AlC2 MAX formation. The defect densities propagate from precursors to final MXenes, enabling the fabrication of a series of Ti3C2Tx MXenes with systematically controlled defect densities. This allows a quantitative correlation between defect density and multifunctional properties including electrical and thermal conductivities, infrared emissivity, electromagnetic shielding effectiveness, Joule heating performance, and oxidation stability. The defect-minimized Ti3C2Tx MXene exhibits outstanding performance, with an electrical conductivity of 26,000 S cm-1, thermal conductivity of 57 W m-1 K-1, electromagnetic shielding effectiveness of 90.5 dB at 10 & micro;m, Joule heating performance of 263 degrees C at 1.5 V, ultralow infrared emissivity of 0.05, and superior oxidation resistance (activation energy of 72 kJ mol-1). Furthermore, this work establishes a comprehensive quantitative framework linking defect structure to multifunctional performance and stability.

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