Flower-like NiCo₂S₄Microspheres Based on Nanosheet Self-Assembly Anchored on 3D Biomass-Derived Carbon for Efficient Microwave Absorption

Possessing both dielectric loss and magnetic loss is desirable for high-efficiency microwave absorbers to achieve promising impedance matching and high attenuation constant. In this work, biomass-derived carbon (BDC)/NiCo2S4 (BNCS) composites were successfully synthesized through growing flower-like NiCo2S4 microspheres on the surface of a three-dimensional (3D) BDC framework using a low-cost, facile, and sustainable process. The results indicated that the precursor dosage had a significant impact on the microstructures, surface morphologies, and electromagnetic parameters of the materials, and the introduction of NiCo2S4 nanosheets obviously enhanced impedance matching and attenuation constant, leading to a strong absorption performance. The minimum reflection loss (RLmin) of BNCS reached -62.74 dB at 2.24 mm and an effective bandwidth of 7.62 GHz at 1.96 mm was achieved, which was much better than that of BDC (-8.41 dB at 2.97 mm). It was apparent that BNCS could serve as a promising candidate for next-generation high-performance microwave absorbers with strong absorption, wide bandwidth, and thin thickness.