Hydrovoltaic Power Generation Depend on Wettability at the Liquid-Solid Interface: Mechanisms, Materials, and...

With the global increase in energy consumption, there is a growing demand for green energy production, which has prompted the development of novel renewable energy sources. Recently, significant momentum has been observed in research on new energy harvesting methods suitable for small devices. In this context, hydrovoltaic power generation, utilizing water due to its ubiquitous presence and easy availability, has emerged as a promising technology. Hydrovoltaic power generation operates by converting the potential energy of water into electrical energy through the interaction between water and materials capable of inducing an electrical potential gradient. The control of material surface wettability, which determines the interaction with water, plays a crucial role in enhancing the electrical output and long-term stability of power generation systems. This review categorizes the mechanisms of hydrovoltaic power generation into flow and diffusion mechanisms, discussing respective case studies based on hydrophobic and hydrophilic substrates. Additionally, representative materials used in hydrovoltaic power generation are discussed and the potential to expand this technology across various fields based on the diverse resources of water is demonstrated. The review concludes with future perspectives, highlighting the applications of hydrovoltaic power generation across multiple domains and outlining directions for future research and development.