Triboelectric enhanced water evaporation-induced electricity generator for low-grade water energy harvesting

Liquid-solid triboelectric nanogenerators (LS-TENGs) and water evaporation-induced electricity generators (WEGs) can be widely utilized for water energy harvesting, for which enhancing their output is crucial for applications. However, classical strategies based on material and structure modifications or coupling with other functional modules offer limited improvements in the output efficiency of LS-TENGs and WEGs. Herein, a synergistic coupling and enhancement model for heterogeneous electricity generation modes is established, leading to the proposal of a triboelectric enhanced water evaporation-induced electricity generator (T-WEG). The T-WEG simultaneously harvests energy from both droplets and microfluidic flows, outputting a positively biased pulse signal with a peak voltage of 19.20 V and a steady voltage of 0.91 V. More importantly, the electrostatic field generated by the charged triboelectric layer enhances ion migration within the evaporation-induced electric layer, boosting the output voltage by 194%. This synergistic enhancement enables the T-WEG to reach a power density of up to 9.68 W∙m−3. Owing to its coupled pulsed-steady signal characteristic and excellent performance, the T-WEG exhibits broad application prospects in harvesting low-grade water energy and powering Internet of Things (IoT) devices.