Aspect ratio design and heterostructure construction of MoO2/NC nanorods for broadband microwave absorption

Abstract

The exploration of high-performance electromagnetic wave-absorbing materials is particularly critical for mitigating electromagnetic pollution. Based on the designability and structural advantages of one-dimensional anisotropic structures, a series of MoO₂/N-doped carbon (MoO₂/NC) heterogeneous nanorods with various aspect ratios are synthesized by hydrothermal, chemical oxidation polymerization and calcination processes. To investigate the effect of the aspect ratio on their microwave attenuation capacity, these fabricated nanorods are compounded with polyvinylidene fluoride (PVDF) under different filler contents. It is concluded that their aspect ratio can effectively regulate their microwave absorption performance. Specifically, the MoO₂/NC-1/PVDF composites acquire an RL_min value of −56.9 dB at 2.9 mm, and the MoO₂/NC-2/PVDF composites obtain an RL_min value of−44.2 dB at a small thickness of 1.8 mm under a filler loading of 15 wt%. With an increment in the aspect ratio, the optimal effective absorption bandwidth (EAB) of the MoO₂/NC-3/PVDF composites extends up to 6.32 GHz at 2.0 mm with a filler content of only 10 wt%, covering the whole Ku band. Meanwhile, the radar cross-section simulations of the MoO₂/NC/PVDF composites further verify their immense potential in practical applications. This work demonstrates that the aspect ratio design is conducive to acquiring regulable and broadband microwave absorption under low filler loadings.