[CoAlO/Ni]@C heterostructures constructed based on the 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 (EMW) radiation and heat accumulation within limited spaces. The design of multiple interfaces and components may enable effective EMW absorption that is harmoniously integrated with superior thermal conductivity features. In this work, sheet-on-sheet heterophase nanostructures were first constructed by assembling Ni(OH)₂ perpendicularly on CoAl-layered double hydroxides (CoAl-LDHs) using a hydrothermal method, followed by surface auto-polymerization of dopamine (PDA) to form [CoAl-LDHs/Ni(OH)₂]@PDA core–shell nanostructures, and finally [CoAlO/Ni]@C (CNC) was achieved with dielectric magnetic integration via pyrolysis. The CNC exhibits 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)⁻¹. 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 composed of nanosheet arrays rely on multiple reflections and scattering to extend the propagation path of EMWs and increase their consumption. The superior thermal conductivity can be ascribed to the 3D graphitized carbon-coated metal particle framework. Furthermore, radar cross-section (RCS) simulations reveal that CNC could achieve desirable stealth in practice. This study introduces an alternative approach for designing a new generation of materials that simultaneously exhibit excellent EMW absorption and thermal conductivity.