Ambient synthesis of one-dimensional core-shell nanocomposites by encapsulating SiC nanowires with layered double hydroxide nanosheets for high-performance microwave absorption application

Abstract

The optimization design of micro/nanostructure and composition is an effective strategy for preparing high-performance electromagnetic wave absorption (EMA) material. Here, we provide a single-step in-situ electrostatic self-assembly growth approach at room temperature for the efficient construction of core-shell structural composites, consisting of bimetallic layered double hydroxides (LDH) nanosheets tightly wrapped around SiC nanowires. The formation of the bimetallic LDH nanosheets shell is caused by the binding of the bimetallic cations to OH−, which mainly arises from the hydrolysis of water induced by the 2-methylimidazole molecule, while the protonated 2-methylimidazole acts as an interlayer equilibrium anion. Through a heat-treatment process under air, the resulting derivatives of Co, Ni-LMc@SiC, and Zn, Ni-LMc@SiC generate excellent EMA properties due to the intrinsic and synergistic properties of the dielectric/magnetic components and the core-shell structure that provides numerous physical contacts and endows the composite with enhanced interfacial polarization and electron transport. As a result, Zn, Ni-LMc@SiC displays the highest RLmin value of −55.59 dB at 2.8 mm and EABmax of 6.28 at 2.4 mm, while Co, Ni-LMc@SiC has the widest EAB of 6.32 GHz at a thinner thickness of 2.2 mm. The successful construction of core-shell structures for LDH and SiC nanowires in such a facile strategy will broaden the application and development of high-performance EMA materials.