Phase-transition-mediated dual-path optimization in SiCnws@TiO₂ aerogels for synergistic microwave absorption and thermal insulation

The development of multifunctional materials capable of simultaneously mitigating electromagnetic (EM) wave and thermal detection threats requires overcoming the intrinsic trade-off between loss capability and impedance matching. Herein, a decoupled dual-path reinforcement strategy is proposed via precise crystalline phase manipulation to construct a SiCnws@TiO₂ aerogel with a biomimetic wintersweet-flower-like porous three-dimensional (3D) network. This strategy independently modulates two distinct loss pathways: a rutile-phase-dominated conductive network that strengthens conduction loss and abundant anatase/rutile heterointerfaces coupled with oxygen‒vacancy defects that intensify polarization loss. Rather than maximizing a single mechanism, the SiCnws@TiO₂ aerogel annealed at 800 °C (TS-3) achieves optimal EM absorption by striking a balanced synergy between the two paths, resulting in excellent impedance matching and enhanced attenuation. Consequently, the optimized aerogel delivers a minimum reflection loss (RL_min) of −49.7 dB and an effective absorption bandwidth (EAB) of 6.8 GHz at a thickness of 2.9 mm. Moreover, the 3D network provides outstanding thermal insulation, with the surface temperature stabilizing at only 42.2 °C under a heating source of 157.5 °C, demonstrating strong potential for infrared stealth. This work establishes a design paradigm for multifunctional stealth materials, showing how a unified nanoarchitecture can concurrently satisfy the conflicting requirements of thermal management and EM wave manipulation in complex operational environments.