A Strong, Tough, and Stable Composite with Nacre‐Inspired Sandwich Structure

Abstract Improving the fracture resistance of nacre‐inspired composites is crucial in addressing the strength‐toughness trade‐off. However, most previously proposed strategies for enhancing fracture resistance in these composites have been limited to interfacial modification by polymer, which restricts mechanical enhancement. Here, a composite material consisting of graphene oxide (GO) lamellae and nanocrystalline reinforced amorphous alumina nanowires (NAANs) has been developed. The structure of the composite is inspired by nacre and is composed of stacked GO nanosheets with NAANs in between, forming a sandwich‐like structure. This design enhances the fracture resistance of the composite through the pull‐out of GO nanosheets at the nanoscale and GO/NAANs sandwich‐like coupling at the micro‐scale, while also providing stiff ceramic support. This composite simultaneously possesses high strength (887.8 MPa), toughness (31.6 MJ m −3 ), superior cyclic stability (1600 cycles), and long‐term (2 years) immersion stability, which outperform previously reported GO‐based lamellar composites. The hierarchical fracture design provides a new path to design next‐generation strong, tough, and stable materials for advanced engineering applications.