Ti3C2TX/Graphene Aerogels for High-Efficiency Hydrovoltaic Power Generation: Performance Optimization and Mechanism Elucidation

The global energy shortage crisis underscores the urgent need for sustainable power generation technologies.This study focuses on the hydrovoltaic performance and underlying mechanism of Ti3C2TX/graphene aerogels (TGAs). The TGAs were fabricated via hydrothermal treatment followed by freeze-drying, which results in a three-dimensional porous microstructure with a large specific surface area, low density, and abundant surface functional groups. TGAs demonstrated exceptional hydrovoltaic power generation performance, with a maximum output power density of 14.59 mW cm⁻3 , outperforming many reported hydrovoltaic materials. The performance of TGAs was systematically evaluated under varying sunlight intensities, in different electrolyte solutions, and with TGAs containing different Ti3C2TX-to-graphene mass ratios. The underlying mechanism was elucidated based on the Stern model of electric double layers, which linked the enhanced performance to increased surface charge density from cation adsorption and the conductive framework of Ti3C2TX. Notably, this study introduced a novel interfacial modification mechanism using dye molecules. Performance tests in dye-containing solutions revealed that the output voltage in the Congo red (CR) + CaCl2 mixture was higher than that in pure CaCl2 solution, attributed to synergistic effects between the dye molecules and the electrolyte. This work provides new insights into the design of high-performance hydrovoltaic materials.