Bio-inspired cellular ceramic with 2D materials for damage tolerant and EMI shielding applications

Ceramic materials are renowned for their exceptional strength and stiffness; however, their applications in structural systems are often limited by their intrinsic brittleness and low toughness. This study introduces cellular ceramics inspired by the stereom structure of the sea urchin ( Echinus esculentus ), featuring a core-shell architecture with a ceramic core and epoxy coating. The disordered cellular preceramic polymer is additively manufactured and then subjected to high-temperature pyrolysis to form a robust ceramic framework. The mechanical performance is enhanced by coating the ceramic architecture with a thin layer of epoxy resin, thereby creating a core-shell structure. The epoxy-coated ceramic exhibits over three orders of magnitude improvement in specific energy absorption (from 0.00061 J/g to 3.1 J/g), owing to the controlled progressive failure enabled by the epoxy coating, which provides local crack confinement and functions as a structural binder that retains fractured ceramic segments. The epoxy-coated architected structures exhibit substantial enhancements in compressive strength and toughness, effectively suppressing catastrophic failure by substantially delaying damage propagation. When graphene and carbon nanotubes (CNTs) are deposited onto the epoxy coating, the composite exhibits enhanced electromagnetic interference (EMI) shielding performance, achieving a shielding effectiveness of >35 dB in the X-band. This multifunctional capability makes the developed material a promising candidate for aerospace, defense, and electronic applications requiring lightweight, multifunctional structural components.