3D Ultralight Hollow NiCo Compound@MXene Composites for Tunable and High-Efficient Microwave Absorption

Abstract

The 3D hollow hierarchical architectures tend to be designed for inhibiting stack of MXene flakes to obtain satisfactory lightweight, high-efficient and broadband absorbers. Herein, the hollow NiCo compound@MXene networks were prepared by etching the ZIF 67 template and subsequently anchoring the Ti₃C₂T_x nanosheets through electrostatic self-assembly. The electromagnetic parameters and microwave absorption property can be distinctly or slightly regulated by adjusting the filler loading and decoration of Ti₃C₂T_x nanoflakes. Based on the synergistic effects of multi-components and special well-constructed structure, NiCo layered double hydroxides@Ti₃C₂T_x (LDHT-9) absorber remarkably achieves unexpected effective absorption bandwidth (EAB) of 6.72 GHz with a thickness of 2.10 mm, covering the entire Ku-band. After calcination, transition metal oxide@Ti₃C₂T_x (TMOT-21) absorber near the percolation threshold possesses minimum reflection loss (RL_min) value of - 67.22 dB at 1.70 mm within a filler loading of only 5 wt%. This work enlightens a simple strategy for constructing MXene-based composites to achieve high-efficient microwave absorbents with lightweight and tunable EAB.

Keywords: 3D hollow hierarchical architecture; High-performance microwave absorption; Tunable EAB; Ultralight.

Fig. 1

Schematic diagram of synthetic process for LDHT and TMOT

Fig. 2

a TEM, b HRTEM, c AFM images of Ti₃C₂T_x nanosheets. d SEM, g TEM images of ZIF-67 precursors. e SEM, h TEM images of NiCo LDH nanocage. f SEM image of hollow LDHT nanostructure. i Zeta potentials image of Ti₃C₂T_x suspension, NiCo LDH and LDHT

Fig. 3

a TEM and d HRTEM images of LDHT. b, c TEM e HRTEM, and f element mapping images of TMOT

Fig. 4

Images of LDHT composite on a leaf and b reed flocculants

Fig. 5

a, b XRD patterns of as-prepared samples, c C 1s, d Co 2p, e Ni 2p, and f Ti 2p spectra of TMOT and Ti₃C₂T_x

Fig. 6

3D RL values of a Ti₃C₂T_x, b LDH, c LDHT-9, d LDHT-12, e LDHT-18 and f LDHT-24 composites with a filler content of 15 wt% at different thicknesses

Fig. 7

a 2D curves of RL at 2.50 mm, b EAB with the filler content of 15 wt%. c RL curves at different loading in PVDF. d characteristic impedance curves, e attenuation constant of as-prepared samples in 15 wt%. f attenuation constant at different loading in PVDF

Fig. 8

3D plots of RL values for various TMOT-x composites

Fig. 9

Schematic illustration of microwave absorption mechanism for TMOT

Fig. 10

Comparison of the MA properties of various related materials