Recent progress on mechanical reinforcement of silica aerogels and their applications

Silica aerogels possess a unique nanoporous network and outstanding properties such as ultralow density and thermal conductivity, making them attractive for aerospace, building energy conservation, and environmental remediation. However, their inherent brittleness, low mechanical strength, and poor fracture toughness severely restrict practical applications. Enhancing mechanical performance while retaining excellent thermal insulation therefore remains a major challenge. This review summarizes recent progress in mechanically reinforced silica-based aerogels from three aspects: architectural design, multiphase compounding, and molecular engineering. Freeze casting, additive manufacturing, and aerogel fiberization are discussed as architectural strategies for constructing ordered, continuous, and anisotropic skeletons. Organic polymers, inorganic fibers or whiskers, and carbon nanomaterials are reviewed as reinforcing phases, with emphasis on multiscale synergy and interface engineering. Molecular-level approaches, including precursor regulation and chemical crosslinking, are also analyzed for improving network connectivity and flexibility. The applications of reinforced silica aerogels in adsorption and separation, acoustic absorption, fire-resistant insulation, and flexible sensing are further outlined. Finally, future directions, including bioinspired hierarchical design, intelligent manufacturing, and artificial intelligence-assisted development, are proposed to guide the design of thermally insulating yet mechanically robust silica aerogels.