Advances in triboelectric nanogenerators in acoustics: Energy harvesting and Sound sensing

Acoustics, as a branch of modern science, holds pivotal significance in advancing sustainable energy and sensing technologies. Despite its potential, the current limitations still persist in acoustic energy harvesting efficiency and acoustic information sensing technology. Triboelectric nanogenerator (TENG), leveraging the coupled mechanisms of contact electrification and electrostatic induction, offer a promising avenue for the development of energy harvesting and sound sensing applications. Its high sensitivity, broad material choices, and versatile structural designs make it particularly suited for this purpose. In this review, we introduce the theoretical foundation of TENGs in acoustics and present a comprehensive overview of triboelectric acoustic transducers, spanning from low-frequency sound to ultrasonic. Furthermore, we summarize the research advancements in triboelectric acoustic devices for sound/auditory sensing, highlighting their integration with machine learning for intelligent voice recognition. These innovative endeavors provide novel solutions across diverse fields such as energy supplementation, biomedicine, wireless communication, human-machine interaction (HMI), and marine localization. Lastly, we discuss the existing challenges and future directions in this domain, proposing strategies to propel the practical deployment of triboelectric technology in acoustics and outlining emerging research directions.