Design of hierarchical 1D-2D NiCo_2O_4 as high-performance microwave absorber with strong loss and wide absorbing frequency

摘要

Nowadays, the studying of high-performance microwave absorber with the features of broad bandwidth and strong absorption to address the electromagnetic wave pollution is still a challenge. Thus, based on the careful design of structure and composition, a novel high-performance microwave absorber of hierarchical 1D-2D NiCo2O4 integrating one-dimension nanofibers and two-dimension microsheets is prepared via facile hydrothermal method and subsequent annealing process. The formed NiCo2O4 can be well adjusted under the different annealing temperature. Particularly, varying the annealing temperature from 280 to 600 degrees C regulates the composition and physicochemical property, further optimizing the microwave absorption performance of hierarchical 1D-2D NiCo2O4. Therefore, when the annealing temperature is 320 degrees C and the fill ratio in the paraffin is 30%, maximum reflection loss and efficient frequency bandwidth below - 10 dB are - 41.8 dB and 5.35 GHz at a thickness of 2 mm respectively. The superior absorption performance is due to conductive loss, dipole polarization loss, multiple scattering and multiple reflection, which illustrates that hierarchical 1D-2D NiCo2O4 could be regarded as a strong-loss, broadband, and lightweight microwave absorber.