PEDOT/PSS Heterointerface Enables Integrated Electromagnetic Wave Absorption and Thermal Protection in Aerogel Composite

Traditional high-density thermal protection systems (TPSs) limit the maneuverability of hypersonic vehicles while lacking stealth capabilities. In this work, we propose a strategy to integrate electromagnetic wave absorption and thermal protection in an aerogel composite by introducing a PEDOT:PSS heterointerface via ethanol-assisted gel impregnation. Ethanol also functions as secondary doping, enabling tuning of the electromagnetic parameters of the aerogel by adjusting the doping level. This can achieve a balance between microwave attenuation and impedance matching in the aerogel, leading to excellent broadband microwave absorption with a minimum reflection loss of −37 dB at 30 mm thickness and an effective bandwidth of 13.3 GHz. During ablation, the PEDOT:PSS heterointerface can also induce a thermal blocking effect that can suppress the melting of high-silica fiber, helping maintain the three-dimensional skeletal support of fiber felt, thereby enhancing the aerogel composite’s resistance to oxyacetylene flame attack. Therefore, the aerogel composite exhibits a low linear ablation rate of 0.03 mm/s under 1 MW/m2 and, after 96 s of exposure to 1800 °C flame, maintains a backside temperature of only 61 °C. This work provides a feasible strategy for achieving integrated electromagnetic wave absorption and thermal protection in aerogel composites, which has potential for next-generation lightweight TPS applications.