Constructing interpenetrating structured NiCo₂O₄/HCNT composites with heterogeneous interfaces as low-thickness...

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetics

Background:

• Advanced microwave absorption materials (MAMs) require low matching thickness, broad effective absorption bandwidth (EAB), and excellent reflection loss (RL).
• Nickel cobaltite (NiCo2O4) and helical carbon nanotubes (HCNTs) are promising components for MAMs due to their unique electromagnetic properties.

Purpose of the Study:

• To synthesize novel interpenetrating structured NiCo2O4/HCNT composites for enhanced microwave absorption.
• To investigate the relationship between structural design, electromagnetic parameters, and microwave absorption performance.
• To explore a facile synthesis approach for low-thickness MAMs.

Main Methods:

• Facile hydrothermal technique followed by a heat-treatment process.
• Synthesis of rod-like NiCo2O4 nanoparticles integrated with HCNT.
• Characterization of structural, electromagnetic, and microwave absorption properties.

Main Results:

• The optimized NiCo2O4/HCNT composite achieved a reflection loss (RL) of -55.9 dB at a low thickness of 1.35 mm.
• An effective absorption bandwidth (EAB) of 4.8 GHz (13.2-18.0 GHz) was obtained at 1.35 mm thickness.
• A broad EAB of 10 GHz was achieved for thicknesses ranging from 1.35-2.10 mm, covering both X and Ku bands.

Conclusions:

• The interpenetrating structured NiCo2O4/HCNT composites exhibit outstanding microwave absorption performance at low thicknesses.
• The enhanced MA is attributed to multiple reflection/scattering, resonance, eddy current loss, conduction loss, and various polarization mechanisms.
• This study presents a simple and effective method for developing low-thickness MAMs using NiCo2O4 and HCNT.