Excellent microwave absorption performance of LaFeO3/Fe3O4/C perovskite composites with optimized structure and impedance matching

Abstract

Compositional optimization and structural design are considered to be effective approaches for improving the microwave absorption (MA) ability of carbon-based absorbers. Herein, we have synthesized the LaFeO3/Fe3O4/C perovskite composites by one-step pyrolysis of 3d-4f metal-organic frameworks (MOFs) at a low temperature. The content of LaFeO3 and Fe3O4 can be efficiently controlled by tuning the pyrolysis temperature. For LaFe-MOF-650 composite, the effective absorption bandwidth (EAB, RLmin ≤ −10 dB) reaches 7.2 GHz at 2.2 mm under a filling ratio of 50 wt%. Further, the effect of hollow and spiral carbon on the MA performance of 3d-4f-MOFs-derived composites is investigated. The minimum reflection loss (RLmin) of the hollow LaFeO3/Fe3O4/C sample with a thickness of 1.82 mm reaches up to −68.3 dB under a filling ratio of 40 wt%. The spiral LaFeO3/Fe3O4/C sample exhibits an RLmin of −42.3 dB and an EAB of 4.70 GHz at an ultra-low thickness of 1.35 mm under a lower filling ratio of 30 wt%. Benefiting from the structural and compositional advantages, the prepared high-efficiency MA materials with optimized impedance matching and attenuation capability are excellent candidates for high-performance MA materials.