High-entropy alloy nanoparticles combined with an SiC coating synergistically boost the electromagnetic shielding performance of a carbon nanotube sponge

It is a critical challenge to construct a robust and efficient electromagnetic shielding system with tunable shielding behavior and interfacial properties to adapt to complicated extreme conditions. Here, we fabricate a ternary SiC@high-entropy alloy (HEA)@carbon nanotube sponge (CNTS) composite with designed heterogeneous interfaces and composition on a wide range of scales. On the atomic scale, the electromagnetic character of the composite can be easily regulated through adjusting the elemental composition of HEAs due to their high entropy effect and the cocktail effect. A nano-meter thick silicon carbide (SiC) layer on the HEA further generates a Schottky junction between the metal–SiC and CNTS–SiC to achieve an outstanding average electromagnetic interference (EMI) shielding performance of ca. 90 dB in the X-band on the nano scale (the maximum EMI SE of the 4 mm-thick sample is greater than 100 dB), accompanied with good elasticity and excellent chemical and thermal resistance to endure acid corrosion and high-temperature annealing on the micro scale. This work paves a pathway for designing and developing potential shielding composites with excellent and tunable EMI shielding performance and comprehensive characteristics for complicated application scenarios.