The Observer reports:

In the early 20th century, Serbian inventor Nikola Tesla dreamed of pulling limitless free electricity from the air around us. Ever ambitious, Tesla was thinking on a vast scale, effectively looking at the Earth and upper atmosphere as two ends of an enormous battery. Needless to say, his dreams were never realised, but the promise of air-derived electricity – hygroelectricity – is now capturing researchers’ imaginations again. The difference: they’re not thinking big, but very, very small.

In May, a team at the University of Massachusetts (UMass) Amherst published a paper declaring they had successfully generated a small but continuous electric current from humidity in the air. It’s a claim that will probably raise a few eyebrows, and when the team made the discovery that inspired this new research in 2018, it did.

“To be frank, it was an accident,” says the study’s lead author, Prof Jun Yao. “We were actually interested in making a simple sensor for humidity in the air. But for whatever reason, the student who was working on that forgot to plug in the power.”

The UMass Amherst team were surprised to find that the device, which comprised an array of microscopic tubes, or nanowires, was producing an electrical signal regardless. [Continue reading…]