This approach could lead to devices to charge cellphones or other electronics using just the humidity in the air. As a side benefit, the system could also produce clean water.
The device itself could be simple, consisting of a series of interleaved flat metal plates.
A cube measuring about 50 centimeters on a side — about the size of a typical camping cooler — could be sufficient to fully charge a cellphone in about 12 hours. While that may seem slow, people in remote areas may have few alternatives."