Interfacial-Engineered Sub-Crystalline Silica Aerogels with Extreme Thermal Anisotropy for Ultrahigh-Energy Laser Protection

While silica aerogels have emerged as promising thermal management materials, their practical applications under extreme conditions such as ultrahigh-energy laser irradiation or thermal shocks exceeding 2000 °C are fundamentally limited by catastrophic thermal insulation failure and mechanical instability. Herein, we report a breakthrough multiphase subcrystalline silica aerogel (MSC-SA) architecture engineered through interfacial-induced crystallization with quartz fibers. By implementing a "inter-layered insulation/in-plane conduction" design paradigm, the MSC-SAs can achieve a feature of extreme thermal anisotropy─combining unprecedented axial insulation with ultraefficient radial heat dissipation. This unique thermal management strategy enables the simultaneous achievement of record-high laser damage resistance with a threshold of 3.0 × 10⁴ W·cm^-2 and protection duration exceeding 5 min, exceptional thermal stability of an ultralow thermal expansion coefficient of 1.0 × 10^-6 °C^1- at 1200 °C, and remarkable mechanical robustness evidenced by interfacial shear strength of 43.7 MPa and compressive strength of 32.0 MPa at 95% strain. Our proposed MSC-SAs are ideal for thermal superinsulation materials capable of withstanding extreme environments, particularly in advanced defense applications against high-energy laser threats.