Drinking-bird-enabled triboelectric hydrovoltaic generator

The evaporation process involves the most significant amount of energy transfer on Earth. Various hydrovoltaic techniques have been proposed to convert evaporation energy into electricity, but they mainly rely on streaming potential that suffers from the limitations of low voltage output. Herein, we report an alternative strategy for harvesting evaporation energy by using water latent heat and the triboelectric effect. We use a natural, evaporation-driven heat engine inspired by a drinking bird toy to convert the latent heat of evaporation into slow-frequency motion and then convert the mechanical energy into electricity via a specialized triboelectric nanogenerator featuring low friction drag. Our drinking-bird triboelectric hydrovoltaic generator (DB-THG) generates >100 V voltage from water evaporation in the natural environment. Using the prototype of DB-THG, we power small electronics such as 20 liquid crystal displays, temperature sensors, and calculators in ambient conditions using water as fuel.