Flexible MXene‐Based Composite Films for Multi‐Spectra Defense in Radar, Infrared and Visible Light Bands

Abstract Simultaneously developing protective electronics film for multi‐spectra, including the radar, infrared (IR), and visible ranges, for both the military and civilian sectors is extremely challenging. The existing multi‐spectra‐compatible materials mainly concentrate on either the radar/IR or IR/visible bands, trailing the rapid evolution of advanced devices for monitoring electromagnetic signals. Here, it is designed and fabricated an ultra‐thin MXene‐based composite film (20 µm) containing black phosphorus (BP) and Ni chains (M‐B‐M(Ni)) with integrated highly efficient thermal IR stealth, visible light absorption, and electromagnetic wave shielding. M‐B‐M(Ni) exhibits an extremely low IR emissivity of 0.1, decreasing the radiation temperature difference between the surrounding environment and target device. BP offers a high solar absorptance of 80%, which guarantees energy conversion from visible light to heat. Moreover, the absorption proportion of the electromagnetic shielding effectiveness for M‐B‐M(Ni) is 16% higher than that of pure MXene films (68.7%), owing to the improved magnetic loss by decoration with magnetic Ni chains. Due to the combined merits of MXene, BP, and Ni chains, M‐B‐M(Ni) opens an avenue for the construction of advanced multi‐spectra compatible materials for versatile applications in thermal IR stealth, electromagnetic wave shielding, and energy transformation.