Flexible Ceramic Nanofibrous Aerogels with Hierarchically Entangled Graphene Networks Enable Full-Frequency Noise Absorption

Traffic noise pollution has posed a huge burden to the global economy, ecological environment, and human health. However, most present traffic noise reduction materials suffer from a narrow absorbing band, high weights, and poor temperature resistance. Here, we demonstrate a facile strategy to create flexible ceramic nanofibrous aerogels (GCNAs) with hierarchically entangled graphene networks, which integrate unique hierarchical structures of opened cells, closed-cell walls, and entangled networks. Under the precondition of independent of chemical crosslinking, high enhancement in buckling and compression performances of GCNAs is achieved by forming hierarchically entangled structures in all three-dimensional space. Moreover, the flexible GCNAs show striking full-frequency noise absorption performances (noise reduction coefficient of 0.56 in 63~6300 Hz) and lightweight features (9.3 mg cm -3 ), together with robust temperature-invariant stability in –100~500 °C. This strategy paves the way for the design of novel fibrous materials for highly efficient full-frequency noise absorption.