In their quest for a truly self-sustaining energy source, EPFL scientists discovered the hydrovoltaic effect, which produces electricity through the evaporation of water. By carefully engineering the silicon-based nanogenerator, the researchers were able to harvest energy from the natural evaporation of seawater to generate electrical power.
Unlike existing renewable resources, this innovation can produce electricity continuously through the gas-liquid interface. Using an arrangement of silicon nanorods that were calibrated for both ion movement and surface charging mechanisms, five times more energy was generated. This technological advance is a new way to collect modular energy, which could soon provide power for IoT devices and wearable technology.
nano generator Which produces continuous electricity from evaporation
The basis of this development is the hydrostatic effect, a phenomenon that results when a liquid flows over charged nanostructures, producing energy. According to the paper published in Nature Communications, the Laboratory for Energy Technologies (LNET) Nanoscience team has found a way to manage the flow of ions in the evaporation process by introducing a silicon semiconductor coupled to an array of hexagonally patterned nanopillars.
With a three-layer design that separates evaporation, ion transport, and charge collection, the researchers found a way to produce usable energy by passing seawater through the nanostructures. Heat and light appear to stimulate the effects of surface charge, and heat and light enhance the surface charge density of semiconductors, thus greatly increasing their efficiency.
Battery-free sensors for the open ocean
The only drawback to any device operating in the ocean is the salinity of the water and the corrosive nature that accompanies it.
In order to make these devices more practical and able to operate in a marine environment for a long period of time, the EPFL team applied a protective oxide layer to the silicon nanopillars that will help stop unwanted chemical reactions between the electronics and salty seawater, which would degrade typical electronic devices.
Robustness will be important when we look at low-power, battery-free sensor networks in the field.
How hydropower can change communication
This technology could go further than just being a laboratory demonstration. Since a usable electric field can be generated by this device as long as there is evaporation, does not need an external power source, and relies solely on ambient heat and light, this system seems ideal for the Internet of Things, as reported in the journal Nature Communications. Low-power, battery-free sensor networks, as well as future wearable technology, will no longer be connected to traditional batteries.