Heterojunction engineering of large-sized Ti3C2Tx MXene with ZnO for enhanced high-frequency microwave absorption and thermal conductivity

Abstract

Polymer composites with superior electromagnetic wave (EMW) absorption properties, such as strong attenuation and broadband absorption, as well as excellent thermal conductivity, are ideal for the preparation of high-frequency, high-power electronic devices. Hence, we designed ZnO/Ti₃C₂T_x MXene heterostructured nanofillers by loading surface-modified ZnO nanoparticles onto large-sized Ti₃C₂T_x MXene nanolayers using electrostatic interactions. Subsequently, PVDF/ZnO/Ti₃C₂T_x MXene (PZM) composites were prepared by blending and hot-press molding process with polyvinylidene difluoride (PVDF) resin. By optimizing the doping ratio of ZnO to Ti₃C₂T_x MXene in heterogeneous interface engineering, the high-frequency microwave absorption and thermal conductivity of the composites were precisely tuned. When the mass ratio of ZnO to Ti₃C₂T_x MXene is 3:2 (PZM-3), PZM shows the best attenuation of electromagnetic waves, with a minimum reflection loss of −47.2 dB at a thickness of only 2.5 mm, and an effective absorption bandwidth of 4.2 GHz (11.12–15.32 GHz). This bandwidth covers almost all operating band of high-frequency microwave communication equipment up to 18 GHz. Meanwhile, its thermal conductivity increases by 120 % compared to pristine PVDF resin. Most surprisingly, when the mass ratio of ZnO to Ti₃C₂T_x MXene is 2:3 (PZM-4), the PZM composites exhibit the best thermal conductivity, which increases by 555 %. Furthermore, radar cross section (RCS) was used to simulate the EMW absorption characteristics of PZM composites in practical application scenarios, confirming that PZM composites have a strong EMW loss capability. This work provides a new path for practical application and deep expansion in the field of efficient microwave absorption and thermal management in complex frequency bands, especially in the high-frequency domain.