Dielectric loss compensation induced by hydroxyl surface grafting protects against microwave absorption attenuation

Internal loss mechanisms in microwave-absorbing materials frequently alter in severe situations with changing hash environmental conditions. Little study has been done on the loss compensation within the dielectric loss. Herein, a straightforward elemental directed synthesis was used to create an oxygen-rich carbon nanosheets (OCN) microwave-absorbing material. It was discovered that submerging the material in saltwater caused a dielectric loss compensating effect. This is triggered by a substantial number of grafted hydroxyl groups. More polarization sites are created by hydroxyl grafting, which significantly increases the material's polarization loss. However, it also destroys the high-energy conjugation systems and weakens the conduction loss. The two effects compensate for one another so that the absorbent material's performance can reach an effective absorption bandwidth of up to 5.33 GHz at a thickness of 1.9 mm after immersion. The hydroxyl graft-triggered dielectric loss compensation effect resulting in a drop in absorption performance is, at best, only 4.1%. Meanwhile, the hydroxyl group adsorbed at the defect forming intramolecular hydrogen bonding fills the defect cavity and prevents additional intrusion of outside corrosion ions. The investigation of corrosion resistance and anti-corrosion of absorbing materials is anticipated to be stimulated, allowing OCN to be used successfully in the marine environment.