Recent Progress in Power Generation from Water/Liquid Droplet Interaction with Solid Surfaces

Water covers approximate to 70% of the Earth's surface and it contains a tremendous amount of energy that remains unexploited. With the advance of nanotechnology, new strategies toward harnessing water energy based on new mechanisms are proposed. Here, the interaction mechanisms between a water droplet and a solid surface for harvesting energy, including water-solid contact electrification in the four basic working modes of a triboelectric nanogenerator and streaming current, are reviewed. Among them, nanogenerators based on the contact electrification show the highest output. Practical applications are also presented, such as sensing application, wearable power generation, all-weather power generation, and blue energy solutions. At last, perspectives and opportunities for using water/liquid-based energy are discussed.