2D Transition Metal Carbides and Carbonitrides (MXenes) for Electromagnetic Interference (EMI) Shielding

<b>2D Transition Metal Carbides and Carbonitrides (MXenes) for Electromagnetic Interference (EMI) Shielding</b><br/><i>Aamir Iqbal¹, and Chong Min Koo¹*</i><br/><br/>¹School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea<br/><br/><br/>*Corresponding author: [email protected] (C. M. Koo)<br/><br/><br/>Two-dimensional (2D) MXenes are a newly discovered family of transition metal carbides, nitrides, and carbonitrides. Their outstanding electrical conductivities of &gt;10⁴ S cm⁻¹in 2D morphology, low density, mechanical flexibility, easy processability, and structural controllability extends their application scope to compete with existing conventional 2D materials. Ti₃C₂T<i>_x</i>, the representative candidate of the MXene family, exhibits an EMI shielding effectiveness of 92 dB at 45 micrometer thickness, whereas a 55-nanometer thick film can provide 99% shielding against EMI, which is outstanding for highly compacted electronics. A transition metal carbonitride, Ti₃CNT<i>_x</i> MXene, with a moderate electrical conductivity provides a shielding effectiveness of 116 dB at 40 micrometer thickness, higher than the more-conductive Ti₃C₂T<i>_x</i> or metal foils of the same thickness. This exceptional shielding performance of Ti₃CNT<i>_x</i> was achieved by thermal annealing and is attributed to an anomalously high absorption of electromagnetic waves in the layered metamaterial-like porous structure. With high absorption of EM waves at minimal thickness, MXenes are ideal for real applications in smart 5G electronics.<br/><br/><br/><b>Keywords: </b>Transition metal carbides, carbonitrides, MXenes, electromagnetic shielding, porous structure.