Strong and Tough Silicon Nitride Aerogel

Ceramic aerogels hold significant promise for high-temperature thermal insulation and lightweight structural applications due to their inherent thermal stability and porous architecture, yet their practical utilization is usually hindered by their intrinsic brittleness and inadequate mechanical strength and toughness. While nanowire-assembled configurations partially mitigate the fragility of conventional ceramic aerogels, their load-bearing capacity remains insufficient, and existing reinforcement strategies often compromise thermal insulation performance due to the increase of the aerogels’ density. Herein, we develop a laminated silicon nitride (Si 3 N 4 ) aerogel via structural engineering that synergistically integrates exceptional mechanical properties with superior thermal insulation. The engineered aerogel achieves a high compressive strength of 176.35 MPa (∼3000-fold enhancement) and modulus of 2.24 MPa (∼100-fold improvement) at a low density of 200 mg/cm 3, coupled with good compressibility (97% strain), toughness (10.42 MJ/m 3 ), thermal insulation performance (a thermal conductivity of 0.0832 W/(m·K)), and high-temperature endurance (up to 1200 °C in air). This work establishes a paradigm for concurrent mechanical-thermal optimization through architectural design, providing a transformative material solution for extreme environments demanding integrated load-bearing capacity and thermal management in aerospace and energy systems.