Strong electric wave response derived from the hybrid of lotus roots-like composites with tunable permittivity

Lotus roots-like NiO/NiCo₂O₄ hybrids derived from Metal-organic frameworks (MOFs) are fabricated for the first time by using flake NiCo-MOF precursors as reactant templates. It was found that a thin sample consisting of 60 wt % NiO/NiCo₂O₄ hybrids in the wax matrix exhibited an effective microwave absorption bandwidth of 4.2 GHz at the thickness of 1.6 mm. The highest reflection loss of -47 dB was observed at 13.4 GHz for a sample with a thickness of 1.7 mm. Results obtained in this study indicate that hybrids of NiO and NiCo₂O₄ are promising microwave absorbing materials with adjustable permittivity, which can exhibit broad effective absorption bandwidth at low filler loading and thin thickness.