Self-powered angle-resolved triboelectric nanogenerator for underwater vibration localization

Precise locating in underwater environment is essential for marine engineering and national security. However, the current technologies usually suffer from energy and complexity issues. Here, a self-powered angle-resolved triboelectric nanogenerator (AR-TENG) is proposed for underwater vibration detecting and locating in a simple and energy-effective fashion. The AR-TENG is made of metal balls and an inverted conical unit consisting of fluorinated ethylene propylene film and multiple sector-like electrodes, where each electrode corresponding to one sensing channel. Each channel of AR-TENG can respond to low-frequency variations with linear electrical outputs and a maximum power density of 1.28 μW·cm⁻² at a load resistance of 200 MΩ. Most importantly, the output voltage ratio of two adjacent channels is only related to the vibration direction, endowing AR-TENG with the capability of vibration direction recognition with an angle resolution of 15°. As a result, the underwater vibration locating can be realized by simply intersecting the vibration directions respectively determined by two AR-TENGs arranged in parallel, performing a locating accuracy of >95 %, assisted with a simple trigonometric function and geometric relation. This new scheme is simple, effective and energy-autonomous, holding great potential for various underwater applications.