Nano-Power: Unlocking New Energy with Nanotechnology

Researchers at EPFL have found a way to use tiny devices to turn evaporation into electricity. This discovery could lead to a huge new source of power.

Evaporation happens all around us, but we rarely think about it. Yet, about half of the sun’s energy that hits the Earth causes things to evaporate. Since 2017, scientists have been trying to use this energy with something called the hydrovoltaic effect. This effect lets us make electricity when a fluid flows over a special surface on a super small device. Inside these devices, evaporation makes the fluid move, kind of like how water moves up a plant’s stem.

Even though we already have hydrovoltaic devices, we don’t fully understand how they work at the tiny scale. Giulia Tagliabue and Tarique Anwar from EPFL wanted to change that. They used experiments and computer models to study how fluids and ions move, and how they interact with the device’s surface. Their goal was to make better hydrovoltaic devices.

Their study, published in the journal Device, shows that these devices can work with fluids that aren’t just pure water. This was a big surprise, as scientists thought only pure water could make these devices work well.

The EPFL team built their device using tiny pillars made of silicon. They made the gaps between the pillars just right for the fluid to flow through. This helped them understand how the fluid’s ions interacted with the device’s surface.

Anwar explains that when fluid flows through the device, it creates electricity because of the ions in the fluid. Tagliabue adds that they found out they can use the device with fluids that have different amounts of ions. This means we can use it with tap water or even seawater, not just pure water.

This discovery opens up lots of possibilities for using hydrovoltaic devices. They could be used to make electricity from evaporation almost anywhere, even from things like sweat. They could also be used to power devices like smart TVs or fitness trackers. Plus, they could help make clean water by removing salt from seawater.

The EPFL team hopes to keep exploring these ideas and make even better devices in the future. Their work could change the way we make electricity and clean water.