Resilient and Antipuncturing Si₃N₄ Nanofiber Sponge

Ceramic nanofibrous nanostructure-based sponges have attracted significant attention due to ultrahigh porosity, low thermal conductivity, large specific area, and chemical stability. From the regulation of the fiber itself to the construction method of 3D networks, efforts are being made to improve the mechanical properties of ceramic sponges for practical applications. So far resilient compressibility has been realized in ceramic nanofibrous-based sponges via structural design, but they still show brittle fracture under a more complex stress state. Herein, we introduced a highly aligned and interwoven Si₃N₄ nanofiber sponge, which exhibits superflexibility, large break elongation (>80%), large-strain reversible stretch (20%), and good resistance to tensile fatigue. The ceramic sponge also displays reversible compressibility up to 60% strain, puncture resistance, high air filtration efficiency (>99.8%), and low pressure drop (38% of cotton fiber), making the ceramic sponge a high-performance wearable respirator to protect us from harm due to PM_2.5 pollution and possible microorganisms.