Abstract: Traditional wave-absorbing materials often exhibit performance degradation or even failure after damage, which limits their suitability for practical engineering applications. Self-healing absorbers have attracted considerable interest in electromagnetic protection. However, the internal continuous conductive network in existing materials tends to undergo undesirable reconstruction upon healing, resulting in degraded electromagnetic wave (EMW) absorption and restricting their practical application. Herein, carbon nanotube microspheres (CNT-s) were used as functional absorbing units, and a supramolecular network with dynamic hydrogen bonds from tannic acid (TA) and polyvinyl alcohol (PVA) was constructed as the self-healing matrix, yielding a CNT-s/TA-PVA metacomposite. The discrete distribution of CNT-s units within the healable matrix not only enables good EMW absorption but also helps preserve their spatial configuration before and after healing, thereby contributing to recoverable absorption performance. At CNT-s content of 13% (in mass), the TPC-3 sample achieves a minimum reflection loss (RL_min) of -60.8 dB at a matching thickness of 1.8 mm and a maximum effective absorption bandwidth (EAB_max, RL<-10 dB) of 4.3 GHz. Moreover, upon exposure to water, the abundant hydrogen bonds in the supramolecular network are activated, enabling room-temperature structural self-healing, and the healed sample still maintains favorable microwave-absorbing performance. This work may provide a promising strategy to mitigate the issue of undesirable conductive network reconstruction in conventional self-healing materials and offers useful insights for designing durable, functionally recoverable intelligent electromagnetic protection devices.

Key words: self-healing absorbing material, carbon nanotube microsphere, metacomposite material, electromagnetic wave absorption performance