Lightweight Co₃O₄/CC Composites with High Microwave Absorption Performance

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetics

Background:

• Growing demand for thin, low-frequency microwave-absorbing materials in military radar technology.
• Need for flexible and high-performance electromagnetic wave attenuation solutions.
• Limitations of existing materials in terms of thickness and absorption bandwidth.

Purpose of the Study:

• To synthesize flexible Co3O4/CC composites from Co-MOFs and carbon cloth (CC) for microwave absorption.
• To investigate the effect of calcination temperature on material properties and microwave absorption.
• To evaluate the microwave absorption performance, including reflection loss and effective absorption bandwidth.

Main Methods:

• Hydrothermal and thermal treatment processes for composite synthesis.
• Calcination of Co-MOFs/CC precursors at varying temperatures.
• Characterization of material structure and dielectric properties.
• Measurement of microwave absorption performance (Reflection Loss, bandwidth).

Main Results:

• Calcination temperature influences the structure, dielectric properties, and microwave absorption of Co3O4/CC composites.
• Minimum reflection loss shifts to lower frequencies with increased calcination temperature and reduced thickness.
• Achieved minimum reflection loss of -46.59 dB at 6.24 GHz with 4.2 mm thickness for 25 wt% filler loading.
• Obtained an effective absorption bandwidth of 3.04 GHz (5.84–8.88 GHz) at a thickness of 3.70 mm.

Conclusions:

• Co3O4/CC composites derived from Co-MOFs are effective and flexible microwave-absorbing materials.
• The study provides insights for developing wideband microwave absorbers below 10 GHz.
• Optimized calcination conditions and filler loading enhance low-frequency microwave absorption capabilities.