Melanin-like nanofibers with highly ordered structures achieve ultrahigh specific electromagnetic interference shielding efficiency

Lightweight, high-performance electromagnetic shielding materials rely on the precise design of electromagnetic response structures. Conventional shielding materials often involve complex fabrication of conjugated composites or graphitization of organic materials, facing challenges in balancing their performance and processability. As such, seeking and designing intrinsically conjugated materials with superior processability is crucial. In this work, we have innovatively engineered those bioinspired polymers with highly ordered microstructures, using a 5, 6-dihydroxyindole ring tetramer framework to construct highly ordered melanin-like nanofibers by tuning π–π stacking. The resulting melanin-like aerogels represent surprising microwave absorption performance, a maximum reflection loss of −68.87 dB, and an effective absorption bandwidth of 5.25 GHz. In the X-band, the aerogel reached the specific EMI shielding efficiency of 47909.9 dB cm2/g. This work represents the first successful extension of melanin-like polymers into the microwave spectrum, demonstrating great potential in the electromagnetic field.