Recent advances in TENGs collecting acoustic energy: From low-frequency sound to ultrasound

As a kind of sustainable and environmentally friendly energy, sound has permeated into our daily lives. Yet, the effective collection of acoustic energy remains limited. The emergence of triboelectric nanogenerators has brought significant breakthroughs in collecting low-frequency sound energy and ultrasonic energy. This review delves into the theoretical basis behind the collection of acoustic energy by TENGs and introduces common structures and materials of acoustic TENGs. Additionally, we systematically summarize the latest developments in triboelectric acoustic transducers (TATs) and triboelectric ultrasonic transducers (TUTs) in various fields such as biotherapy, localization, and charging. These innovative developments lay the foundation for advancements in areas like medical health, flexible wearable sensors, and ocean monitoring. Finally, we thoroughly discuss the challenges and prospects of this field, aiming to promote the large-scale collection and utilization of acoustic energy.