High‐performance thermal insulating silicalite‐1 zeolite ceramics enabled by cold sintering

The simultaneous achievement of robust mechanical and thermal insulating performance remains a significant challenge in porous ceramic materials for safeguarding sensitive microelectronic devices under extreme conditions. Here, we present a controlled cold sintering process to prepare silicalite‐1 zeolite ceramics that overcome the intrinsic trade‐off between mechanical robustness and thermal insulation, with a remarkably low thermal conductivity of 0.55 W·m 1 ·K −1 at room temperature combined with an exceptionally high compressive strength of 111 MPa. The outstanding thermal insulating property and load‐bearing capacity originates from the precisely engineered hierarchical structure within zeolite ceramics that comprises ordered micropores restricting the free path of phonons while maintaining structural integrity, tailored macropores and mesopores suppressing gaseous heat conduction through Knudsen effects, and an amorphous phase for submicron‐welding on the interfaces enhancing mechanical robustness. Furthermore, the zeolite ceramics exhibit excellent thermal stability up to 800°C. This work establishes a microstructure‐engineered strategy for designing advanced thermal insulating materials, providing a viable solution for microelectronics protection under extreme conditions.