A PVDF/PU-based composite 3D flexible piezoelectric nanofiber aerogel for acoustic energy harvesting and noise reduction

Noise has become a significant global pollutant but is considered unconventional energy. General, flexible materials like fiber and fabrics cannot substantially improve noise reduction, especially in middle frequencies. This investigation presented a novel strategy based on acoustic energy harvesting. A kind of aerogel composed of strongly piezoelectric nanofiber was prepared using the Decentralized Freeze-Casting method. The aerogel demonstrates the function of absorbing low-frequency energy and medium to high-frequency sound in relation to noise. The sound absorption coefficient in the frequency test band can reach 0.58, and the noise reduction coefficient (NRC) can reach 0.36. The maximum open-circuit voltage and short-circuit current tested during the acoustic-electrical conversion process are 48.2 V and 4.1 μA, respectively, and can be stored and used. In addition, the prepared nanofiber aerogel has good waterproof and mechanical properties. This work has a promising application in future noise management and acoustic energy conversion.