MOFs-derived CoNi@C composites with ant-nest architecture for high-performance ultrawideband microwave absorption

The widespread deployment of 5   G technology has intensified the demand for electromagnetic wave absorption materials to mitigate escalating electromagnetic pollution. Herein, we reported a bioinspired ant-nest-like CoNi@C composite synthesized through a facile hydrothermal method followed by pyrolysis treatment. A lamellar CoNi-MOF precursor was first constructed, and the molar ratio of cobalt to nickel was systematically adjusted to enhance carbon graphitization, thereby tailoring the electromagnetic parameters of the composite. The synergistic interplay between the optimized composition and the unique hierarchical architecture endowed the nanocomposite with exceptional microwave absorption performance. Specifically, the ant-nest-like porous structure facilitated impedance matching, interfacial polarization, and multi-scale attenuation of incident microwaves. The Co 2 Ni 3 @C composite achieved an effective absorption bandwidth (EAB, RL ≤ -10 dB) of 6.47   GHz, with a minimum reflection loss of -50.92   dB at 13.05   GHz with a mere 30   wt% filler loading. This work establishes a versatile MOF-derived strategy for designing high-performance electromagnetic absorbers with ultrawide bandwidth and lightweight advantages.