High-voltage hydrovoltaic generator based on micro/nano multi-scale superhydrophilic SiO2@activated carbon with enhanced capillary infiltration performance

Abstract

At least 60 petawatts (10¹⁵ watts) of energy can be absorbed and released annually through the ubiquitous water cycle, but only a fraction of it is exploited. The prospect of harvesting energy from water evaporation and streaming has garnered increasing attention. Nevertheless, there still exist challenges, including insufficient liquid–solid interface contact and inadequate liquid transport. Herein, a synergistic composite material system comprising micron-scale activated carbon and nano-scale silicon dioxide particles via multistep ball milling processes is introduced. The superhydrophilic material combined with a hierarchical structure enhances capillary infiltration performance, thus ensuring continuous liquid flow and sustained transpiration. As a result, the hydrovoltaic generator achieves efficient energy harvesting (an open-circuit voltage of >4.3 V) and environmental monitoring (response to variations in sunlight intensity and wind speed). Notably, the device can maintain high voltage output for over one year, demonstrating its long-term stability. This study can provide guidelines for effectively harnessing sustainable green energy sources in the future.