Simultaneous solar steam and hydrovoltaic power generation from a volcanic-shaped surface-area-enhanced cement‑carbon composite

Abstract

Simultaneous dual-energy harvesting has gained significant interest in the research community due to its ability to provide substantial benefits at once. By combining solar thermal interfacial evaporation (STIE) with hydrovoltaic (HV) mechanisms, researchers have developed a promising approach to generate both freshwater and electricity simultaneously. In this study, a novel volcanic-shaped device, coated with a salt-treated porous cement‑carbon composite, was created to achieve impressive performance in both evaporation and power generation. The device demonstrated an evaporation rate of 2.6 kg/m²/h, a maximum voltage of 0.5 V, and a current of 42 μA under standard sunlight conditions (1-sun illumination). Additionally, the device showed excellent capabilities in purifying water and delivering power, making it suitable for large-scale applications. Experiments were conducted to evaluate its power generation performance, successfully powering light-emitting diodes and small electronic devices such as calculators and thermocouples. A solar still with an average light exposure area of 644 cm² was also constructed, producing approximately 330–345 mL of freshwater over 8 h. The total dissolved solids (TDS) in the collected water were significantly reduced from 772 ppm in the original bulk water to just 13 ppm, confirming its suitability for human consumption. This innovative device has the potential to address critical future energy needs by providing both freshwater and electrical power sustainably and efficiently.