Microfiber-Based Triboelectric Acoustic Sensors Enable Self-Powered Ultrasonic Localization and Tracking Underwater.

Underwater ultrasonic detection is critical for marine security, playing a vital role in resource development, environmental protection, and national defense. However, existing detection systems, which primarily rely on active scanning technologies, are hindered by high costs, significant energy demands, and challenges in achieving large-scale deployment. Here, we introduce a microfiber-based triboelectric acoustic sensor (MTAS) featuring a core-shell hierarchical structure, offering a self-powered solution for precise measurement of underwater ultrasound source distance. By leveraging the principles of contact electrification/triboelectrification and electrostatic induction, the MTAS efficiently converts complex ultrasonic vibrations into real-time electrical signals. The MTAS demonstrates rapid response times as low as 8.6 μs, a high signal-to-noise ratio of 29.8 dB, and the capability to detect ultrasonic sources with power levels above 1.6 W via time-difference-of-arrival analysis. To address large-scale sea applications, we further propose a distributed network that integrates multiple MTAS units capable of precise ultrasonic source localization and real-time motion trajectory visualization. This innovation represents a transformative approach, combining self-powered operation, ease of deployment, and high imperceptibility, paving the way for large-area, energy-efficient submarine security systems. Such advancements redefine the paradigm of underwater target detection, aligning technological innovation with the pressing demands of marine safety and environmental sustainability.