Self-healing microwave absorbing materials based on sandwich/hollow-structured carbon-coated carbonyl iron

Metal-based absorbing materials (MA) have attracted considerable attention in the field of electromagnetic wave absorption due to their low cost and excellent magnetic loss. However, their relatively high density, single electromagnetic loss mechanism, and poor corrosion resistance of the coating hinder practical applications. Constructing specific structures during the preparation of absorbing materials, and introducing self-healing functionality for enhancing absorbing coating durability represent a highly promising solution. Herein, a high-performance microwave absorbing material with self-healing capability was fabricated. By constructing sandwich/hollow structures during the compounding process of metal-based absorbing material carbonyl iron (CIP) with carbon materials, carbon-coated CIP (CMP@C) was successfully prepared. CMP@C exhibited excellent absorbing performance with a minimum reflection loss (RL_min) as low as −57.07 dB, and its density was reduced by nearly 5 g/cm³ compared to pure CIP. Benefiting from the dynamic reversible self-healing characteristics of diselenide bonds (-Se-Se-), the damaged CMP@C-Coating after self-healing showed only a 0.08 GHz decrease in maximum effective absorbing bandwidth (EAB_max), demonstrating outstanding self-healing performance and absorbing stability. This study not only proves the effectiveness of constructing hollow and sandwich structures in CMP@C, but also highlights the tremendous potential of dynamic reversible -Se-Se-in self-healing absorbing coatings.