Dopants versus defects: Intense confrontation of nitrogen-doped Ti3C2Tx for enhanced electromagnetic interference shielding

Abstract

MXene has been extensively studied in electromagnetic interference (EMI) shielding. In this work, the defects-rich nitrogen-doped Ti3C2Tx (N-doped Ti3C2Tx) was fabricated for EMI shielding. An intense confrontation of dopants versus defects was observed: N dopants offering extra electrons improved electrical conductivity. And the defects-rich characteristics contributed to its reduction, which consisted of crumpled morphology, structural collapse, the introduced N heteroatoms, and pore nature. The end of this conflict revealed that heteroatoms N led to a significant improvement of conductivity and suppressed the negative impact of defects, resulting in the reflection-dominant EMI shielding feature. Owning to greater advantage of dopants, the N-doped Ti3C2Tx prepared at 550 °C/paraffin composite with the most defects exhibited the highest conductivity. And it achieved the maximum total EMI shielding effectiveness from 8.0 to 12.4 GHz (covering the entire X-band) of 62.15 dB. This work presents a new paradigm for MXene-based materials utilizing the structure-property relationship and manifests an enormous application promise for new high-efficiency EMI shielding materials in the future.