Multi-dimensional C@NiCo-LDHs@Ni aerogel: Structural and componential engineering towards efficient microwave absorption, anti-corrosion and thermal-insulation

In recent years, the construction of multidimensional structures has been considered as an effective method to optimize microwave absorbing materials; however, the application scope of absorber is significantly restricted because of the complexity of the environment. Herein, a multidimensional pine nut shell-derived carbon@NiCo-layered double hydroxides@Ni chains (C@NiCo-LDHs@Ni) aerogel was successfully synthesized through a simple solvothermal and freeze-drying method. The two-dimensional (2D) NiCo-LDHs were uniformly attached to the surface of the three-dimensional (3D) carbon skeleton in the form of waves or thin layer, subsequently forming a unique dimensional gradient with the onedimensional (1D) Ni chains. C@NiCo-LDHs@Ni, as a multi-component aerogel, has excellent impedance matching to capture more electromagnetic waves, while the multiple losses from multiple components converted the incident electromagnetic waves into other forms of energy. In addition, the unique 3D structure extends the propagation path, contributing to the further attenuation of electromagnetic waves. The minimum reflection loss (RLmin) of C@NiCo- LDHs@Ni is -57.4 dB at 13.3 GHz, and the effective absorption bandwidth (EAB, RL < 10 dB) covers 6.4 GHz at a layer thickness of 2.5 mm. Benefiting from its special multidimensional structure, the aerogel exhibits outstanding thermal insulation, compression resistance, and anticorrosive performances, thus paving the way for application of high-efficient microwave absorbing materials in complex environments. (c) 2022 Elsevier Ltd. All rights reserved.