A Eutectic‐interface Engineered Al ₂ TiO ₅ Nanofibrous Aerogel for Superinsulation Under Extreme Conditions

ABSTRACT 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 (Al 2 TiO 5 ) 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 Al 2 O 3 –TiO 2 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.