MXene/Co3O4 composite material: Stable synthesis and its enhanced broadband microwave absorption

Microwave absorbers serve the purpose to ensure the transmission efficiency and accuracy in 5G telecommunications. Two-dimensional MXene has great potential in absorbing microwave. In this study, MXene(Ti 3 C 2 T x )/Co 3 O 4 composites are successfully fabricated by a facile and stable hydrothermal treatment in concentrated strong base and Argon environment, followed by a one-step annealing process. Phase composition , chemical state of elements, morphology and structure of the new composite materials are studied by systematical characterization. It is revealed that adsorbed Na + ions and terminations, which are generated at the interface during hydrothermal treatment in concentrated NaOH solution, can protect the Ti 3 C 2 T x from being decomposed. The synthesis mechanism is also proposed for stable fabrication of other MXene-based composite materials. The MXene/Co 3 O 4 composite is able to perform single-band absorption, multiband absorption and even broadband absorption in 2–18 GHz band by tuning its composition and thickness. Particularly, better than 90% absorption in a wide range of 10.8–17 GHz can be achieved with a thickness of just 2 mm. Enhanced wideband absorption originates from the multilayer structure , the surface defects , the conductivity of Ti 3 C 2 T x and the capacitance structure of Co 3 O 4 . Ultrathin and broadband high absorption features make the material a promising candidate for future application.