A Eutectic-interface Engineered Al₂TiO₅ Nanofibrous Aerogel for Superinsulation Under Extreme Conditions

Ceramic aerogels that are both thermal super-insulators and mechanically robust under extreme temperatures are urgently needed yet elusive, due to the inherent trade-off between thermal resistance and thermomechanical stability. Here, we solve the problem by reporting a 3D, elastic aluminum titanate (Al₂TiO₅) nanofibrous aerogel crafted via a eutectic-interface engineering strategy. This approach employs a fully aqueous, scalable roll-to-roll electrospinning process, enabling the low-temperature synthesis of a co-continuous Al₂O₃-TiO₂ eutectic architecture-a structure previously attainable only in dense ceramics through ultra-high-temperature melt growth. The resulting aerogel (density: 25 mg·cm^{- 3}) achieves an ultralow thermal conductivity of 0.033 and 0.103 W·m^{- 1}·K^{- 1} at 25 and 1000°C, respectively. Moreover, the aerogel can resist direct flame at 1300°C without structural failure, and recovers elastically up to 90% after repeated compression at 50% strain. This superior performance arises from its eutectic interfaces, which act as efficient phonon scatterers for thermal insulation while also providing intrinsic thermal stability. This work not only demonstrates a viable, sustainable path for mass-producing elastic ceramic aerogels but also establishes a new material design paradigm, transforming brittle eutectic oxides into lightweight, elastic thermal super-insulators for aerospace and energy applications.