Bifunctional CoNi/MXene@Wood with vertical aperture structure for electromagnetic wave absorption and infrared stealth

Abstract

Multifunctional integrated electromagnetic wave absorption (EMA) materials have been widely functional within the gigahertz range. Adjusting the electromagnetic parameters by decorating with magnetic/dielectric components to optimize the electromagnetic attenuation is an effective strategy for obtaining lightweight and efficient electromagnetic wave-absorbing materials. In this work, natural wood was pretreated by high-temperature carbonisation and polydopamine (PDA) modification, and CoNi and Ti₃C₂T_x-MXene were sequentially introduced into the pretreated carbonised wood with distinctive rectangular honeycomb cells by hydrothermal reaction and vacuum impregnation methods. Through structural design and material composition regulation, synergistic dielectric and magnetic loss effects were achieved. The optimized impedance endows CoNi/MXene@Wood-1.5 with a minimum reflective loss (RL_min) of −56.8 dB and an effective absorbing bandwidth (EAB) covering the entire X-band. Additionally, CoNi/MXene@Wood can realize the thermal infrared stealth of protected targets in different environments with low and stable thermal conductivity (0.219–0.267 W m⁻¹ K⁻¹) over a temperature range of 298–673 K. The structural design and dielectric constant adjustment provide strategies for obtaining high EMA performance materials and infrared stealth applications.