Spontaneous and sustainable multifunctional transpiration generator for simultaneous harvesting of electricity, freshwater and salt

Evaporation driven power generation technology has attracted global interest due to its eco-friendly nature and ubiquitous availability. However, the lower performance, discontinuity of power generation and limited function greatly hinder its wide application. To achieve continuous power generation and simultaneous production of freshwater and salt from seawater evaporation, we constructed a spontaneous sustainable multifunctional transpiration generator (SSMTG) with high performance and multi-functions. The continuous power generation was realized by maintaining a controllable dry/wet interface on a carbon black coated cotton cloth, and capillary-driven spontaneous water supply was achieved via a cotton rope. The open circuit potential, short-circuit current and peak power density of a single SSMTG with size of 9 cm × 3 cm × 0.01 cm were ∼ 0.4 V, ∼23.6 μA and ∼ 14.8 μW/cm3, respectively. In addition, the impacts of various factors on the electricity generation were studied and the underlying mechanism was primarily explored. The device can work for more than 24 h, which also can produce 29 mL of freshwater and 0.825 g of salt. When connected in series and parallel, it could supply power for some common electronic devices, such as an electronic watch. The SSMTG can obtain fresh water and salt while producing electricity, which provides a sustainable and versatile source for various applications.