MXene-based hydrovoltaic electricity generators and their coupling with other energy harvesting systems

MXenes, a class of two-dimensional transition metal carbides and nitrides, have garnered significant attention for their unique properties, making them promising candidates for next-generation energy harvesting technologies. Among these, emerging MXene-based hydrovoltaic electricity generators (HEGs), including moisture electricity generators (MEGs), evaporation electricity generators (EEGs), reverse electrodialysis electricity generators (REGs), and droplet electricity generators (DEGs) have demonstrated exceptional performance in converting energy in environmental water such as moisture, water, wave, and droplets into electricity. Additionally, the synergistic coupling of MXene HEGs with other energy harvesting systems, such as triboelectric nanogenerators (TENGs) and thermoelectric generators (TEGs), offers new avenues for enhancing power generation performance and expanding application scenarios. This review systematically examines the structures and properties of MXenes, their application in various HEGs, and the recent advancements in their integration with other energy harvesting systems. Furthermore, we discuss the challenges and future opportunities for MXene-based devices in multi-functional energy harvesting platforms.