MXene–modulated 3D crosslinking network of hierarchical flower–like MOF derivatives towards ultra–efficient microwave absorption property

Lightweight and high–efficiency microwave absorption materials with tunable electromagnetic properties still remain challenging to meet the increasing demand for portable electronics. In this work, MOF derivatives/MXene crosslinking networks were successfully synthesized through connecting flower–like MOF derivatives with 2D flexible MXene flakes. The combination of the enhanced interfacial polarization derived from the flower–like structure and the conductivity loss originated from the network structure endows the composites with remarkable microwave absorption (MA) performance. For the sample of CoO/MXene–15 (COT–15) with 5 wt% loading exhibits an RLmin of –52.23 dB with corresponding effective absorption bandwidth (EAB) of 4.88 GHz at 1.90 mm. The introduction of Ni can effectively optimize impedance matching and regulate the permittivity with downward trend as the increase of Ni addition. CoO/NiCo2O4/MXene (CN1OT) with various filler loading can achieve excellent MA property despite of adjusting adherent MXene content in a large range. For instance, the strong RLmin of 47.17 dB and the wide EAB of 5.44 GHz are obtained for CN1OT–15 at 2.90 mm, when the filler loading in PVDF is only 5 wt%. Besides, CN1OT–15 (10 wt%) possesses an optimal RLmin of –58.37 dB and broad EAB of 4.24 GHz at the thickness of 1.50 mm. Our work manifests that 3D crosslinking network based on MOF derivatives may be an effective strategy in constructing lightweight and high–efficient microwave absorbents, and promoting the development of heterobimetallic oxides in the MA field.