We’ve already heard about so-called “fog harps” that use thin wires to collect airborne water droplets, providing drinking water even in arid regions. Well, an experimental new device also uses wires to capture water vapor, although it proceeds to generate electricity.
Developed by a team at the University of Massachusetts Amherst, the air powered generator or “Air-gen” incorporates an ultra thin film made of nanowires. Less than 10 thousandths of a millimeter thick, that film is sandwiched between two flat rectangular electrodes, although the one on top covers only part of the film, leaving the rest exposed to the air.
Produced by a type of bacteria known as Geobacter, the nanowires themselves are made of an electrically-conductive protein. Because of this quality – along with their surface chemistry and the small size of the pores between them – the wires generate an electrical current between the two electrodes, whenever they absorb water vapor from the air.
“We are literally making electricity out of thin air. The Air-gen generates clean energy 24/7,” said Dr. Jun Yao, an electrical engineer at the University of Massachusetts Amherst.
It’s the most amazing and exciting application of protein nanowires yet, added Professor Derek Lovley, a microbiologist at the University of Massachusetts Amherst.
“It has significant advantages over other forms of renewable energy including solar and wind, because unlike these other renewable energy sources, the Air-gen does not require sunlight or wind, and it even works indoors,” Professor Lovley said.
The current generation of Air-gen devices produces a sustained voltage of around 0.5 V across a 7-μm-thick film, with a current density of around 17 µA/cm2.
“I found that that exposure to atmospheric humidity was essential and that protein nanowires adsorbed water, producing a voltage gradient across the device.”
Next steps the scientists plan include developing a small Air-gen ‘patch’ that can power electronic wearables such as health and fitness monitors and smart watches, which would eliminate the requirement for traditional batteries.
“The ultimate goal is to make large scale systems,” says electrical engineer Jun Yao, who led the research along with microbiologist Derek Lovley. “For example, the technology might be incorporated into wall paint that could help power your home. Or, we may develop stand-alone air-powered generators that supply electricity off the grid. Once we get to an industrial scale for wire production, I fully expect that we can make large systems that will make a major contribution to sustainable energy production.”
Source : newatlas.com , sci-news.com