Compressible Highly Stable 3D Porous MXene/GO Foam with a Tunable High-Performance Stealth Property in the Terahertz Band

In this work, a three-dimensional (3D) porous MXene/GO foam (MGOF) was successfully synthesized and exhibited an excellent terahertz stealth property covering a whole measurement frequency of 0.2–2.0 THz. This is due to the ingenious assembly of two functional two-dimensional materials that have different advantages. The multiscale micro-nanostructure constructed with the 3D porous MGOF can effectively increase the terahertz scattering and refraction. Furthermore, MXene sheets with high conductivity can enhance the responsiveness to the terahertz wave. By adjusting the content of MXene in the MGOF, it exhibits a maximum reflection loss (RL) of 37 dB with a 100% qualified frequency bandwidth (RL > 10 dB), which is the most outstanding result in the available reference. In addition, the optimal average terahertz RL values of MGOF were up to 30.6 dB, which is 100% higher than the best data presented in previous work. Benefitting from an ultralow density, a high RL value, and a wide bandwidth, the maximum specific average terahertz absorption performance can reach 4.6 × 104 dB g–1 cm3, which is more than 4000 times that of other materials. In addition, the regulation of the terahertz absorption property through microstructure and morphology control is reported for the first time.