A MXene-modulated 3D crosslinking network of hierarchical flower-like MOF derivatives towards ultra-efficient microwave absorption properties

Fabrication of lightweight and high-efficiency microwave absorption materials with tunable electromagnetic properties still remains 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 originating from the network structure endows the composites with remarkable microwave absorption (MA) performance. The sample of CoO/Ti3C2Tx MXene-15 (COT-15) with 5 wt% loading exhibits a minimum reflection loss (RLmin) of -52.23 dB with a 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 a downward trend with the increase of Ni addition. CoO/NiCo2O4/Ti3C2Tx MXene (CN1OT) with various filler loadings can achieve excellent MA properties despite adjusting the adherent MXene content in a large range. For instance, a strong RLmin of -47.17 dB and a 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 a broad EAB of 4.24 GHz at the thickness of 1.50 mm. Our work manifests that fabrication of 3D crosslinking networks based on MOF derivatives may be an effective strategy in constructing lightweight and highly efficient microwave absorbents, and promoting the development of heterobimetallic oxides in the MA field.