Hydrovoltaic energy from water droplets: Device configurations, mechanisms, and applications

Water, the source of life, contains immense energy and manifests in diverse forms. Hydrovoltaic technology enables the direct interaction between water and materials to generate electricity, a vital necessity for industry modernization. Due to the ubiquitous presence and easy availability of falling water, hydrovoltaic energy derived from water droplets has attracted considerable attention and shown great potential in raindrop energy harvesting. In this review, a comprehensive summary of the latest advancements in harvesting hydrovoltaic energy from water droplets is presented, with a focus on the configurations and underlying mechanisms of hydrovoltaic devices. Additionally, a brief discussion on the applications of droplet-based hydrovoltaic devices is presented, along with future prospects for this energy-harvesting technology.