Carbonized wood with ordered channels decorated by NiCo2O4 for lightweight and high-performance microwave absorber

Abstract

Wood-derived carbon has a 3D porous framework composed of through channels along the growth direction, which is a suitable matrix for preparing electromagnetic wave (EMW) absorbing materials with low-cost, light-weight, environmentally friendly and excellent MA performance. Herein, the carbonized wood decorated by short cone-like NiCo2O4 (CW@NiCo2O4) with highly ordered straightway channels architecture were successfully manufactured through a facile calcination procedure. Finite Element Analysis (FEA) simulation is carried out to detect the interaction between the prepared material and EMW when the ordered channels are arranged in different directions. Simultaneously, the microwave absorption properties of all samples are investigated in terms of complex permittivity and permeability. The horizontal arrangement of the through channels of CW@NiCo2O4 (H-CW@NiCo2O4) exhibits a strong reflection loss value of -64.0 dB at 10.72 GHz with a thickness of 3.62 mm and a low filling ratio of 26wt% (with the density of 0.98g·cm− 3), and the effective absorption bandwidth (EAB) is 8.08 GHz (9.92-18.0 GHz) at the thickness of 3.2 mm. The extremely advantageous structure of H-CW@NiCo2O4 is the key to achieving excellent MA property, which enables multiple EMW loss mechanisms to be effectively realized. What’s more, the introduction of NiCo2O4 increases the values of \({\epsilon }^{\text{'}}\) and \({\epsilon }^{\text{'}\text{'}}\), resulting in enhanced dielectric loss. This research provides a low-cost, sustainable and environmentally friendly strategy for using carbonized wood to fabricate microwave absorbers with strong attenuation capabilities and lightweight.