Flower-like NiCo₂S₄ Microspheres Based on Nanosheet Self-Assembly Anchored on 3D Biomass-Derived Carbon for Efficient Microwave Absorption

Abstract

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.

Excellent microwave absorbing performance of biomass-derived activated carbon decorated with in situ-grown CoFe2O4 nanoparticles

“…al. achieved RL max = -62.74 dB at 2.24 mm and an excellent EAB of 7.62 GHz at 1.96 mm5 . These results suggest the potential of activated carbon/magnetic material based composites as MW absorbing material.…”

“…A high-performance MW absorber amongst traditional properties like strong microwave absorption and wide effective absorption bandwidth (EAB) which means frequency bandwidth having reflection loss (RL) < -10 dB, should also possess lightweight, thin thickness, good thermal stability and so on 5,6 . Due to outstanding dielectric loss properties, carbon based materials such as graphene and carbon nanotubes (CNT) had been widely used for MW absorbing applications.…”

“…Due to outstanding dielectric loss properties, carbon based materials such as graphene and carbon nanotubes (CNT) had been widely used for MW absorbing applications. They have excellent thermal stability, lightweight, superior electrical and mechanical properties 5,7 , which are quite essential for an enhanced MW absorber. But their high conductivity leads to impedance mismatch thus reducing their performances [8][9][10] .…”

“…Therefore, by combining the carbon-based materials with magnetic loss material would reduce these problems and would show better MW absorption properties like: CoFe 2 O 4 hollow sphere/graphene composite 12 , Co-doped NiZn ferrite/graphene nanocomposite 1 , Fe 3 O 4 -coated CNTs 13 , Li 0.3 Zn 0.3 Co 0.1 Fe 2.3 O 4 @MWCNT 14 , CoFe 2 O 4 /N-doped mesoporous carbon 15 , CoFe 2 O 4 /rGO porous nanocomposite 16 and Ni/Carbon Foam 17 , but these carbon based composites has high processing cost and are difficult to make at large scale which limits their applications 5,8 .…”

“…a frequency bandwidth with a reflection loss (RL) of o À10 dB, and should be lightweight with low thickness and good thermal stability. 5,6 Due to their outstanding dielectric loss properties, carbon-based materials such as graphene and carbon nanotubes (CNTs) have been widely used in MW absorbing applications. They have excellent thermal stability, light weight, and superior electrical and mechanical properties, 5,7 which are essential for enhanced MW absorbers.…”