Heterostructure of [CoAlO/Ni]@C constructed based on interface and component coupling effect toward microwave absorption and thermal conductivity

Abstract

The escalating demand for miniaturization and increased power in electronics presents substantial challenges in dealing with electromagnetic wave radiation and heat accumulation within limited spaces. The design of multiple interfaces and components may attain effective electromagnetic wave (EMW) absorption that is harmoniously integrated with superior thermal conductivity features. In this work, sheet-on-sheet heterophase nanostructures were firstly constructed by assembling Ni(OH)2 nanosheet arrays perpendicularly on the CoAl-layered double hydroxides (CoAl-LDHs) nanosheets using hydrothermal method, followed by surface auto polymerization of dopamine (PDA) to form [CoAl-LDHs/Ni(OH)2]@PDA core-shell nanostructures, and finally achieve [CoAlO/Ni]@C (CNC) heterophase nanostructures with dielectric magnetic integration via pyrolysis. The CNC heterophase nanostructures exhibit a high reflection loss (RL) of −61.8 dB with an effective absorption bandwidth (EAB) of 4.8 GHz at 1.81 mm, and the thermal conductivity is 0.572 W/(m•K). The significant microwave attenuation can be primarily attributed to the formation of numerous interfaces by heterostructures, which enhance the polarization relaxation loss. In addition, the three-dimensional (3D) channels are formed by the nanosheet arrays with substantial voids, thus optimizing electromagnetic parameters. The superior thermal conductivity can be ascribed to the in-situ formation of a 3D graphitized carbon-coated metal particle framework. This structure not only increases electrical conductivity loss but also offers abundant pathways for effective heat dissipation. Furthermore, the radar cross-section (RCS) simulations reveal that the material could achieve a desirable stealth effect in practical applications. This study introduces an alternative approach for designing a new generation of materials that simultaneously exhibit excellent EMW absorption and thermal conductivity.