Floating electricity generator for omnidirectional droplet vibration harvesting

Summary There has been a surge of interest in droplet-based triboelectric nanogenerators, facilitating the durable and sustainable harnessing of slow and periodic mechanical energy resources. A major challenge faced by most of these devices is the concurrent achievement of high electrical outputs and omnidirectionality, which hampers their immediate implementation in real-world slow and periodic energy harvesting scenarios. We present a floating-droplet-activated electricity generator featuring asymmetric electrodes together with the switching of an internal circuit, with a current output of ∼107.6 μA, a power density of 1.2 kW/m3, and a charge density of 31.2 mC/m3. When multiple devices were parallelly integrated, the current output reached 1.2 mA at a waving frequency of 0.28 Hz. Furthermore, the omnidirectionality and stability of the device have been examined, demonstrating that our device is applicable in any marine conditions and can harvest sustainable and extensive energy from natural vibrations.