An iPhone 6 case has been developed that allows users to "download power from the air", according to its creators.
US-based startup Nikola Labs demonstrated the $99 (£65) iPhone case at TechCrunch Disrupt NY, revealing that it is capable of converting radio frequencies, such as WiFi signals, into electricity.
"We're using 19th Century technology to power 21st century mobile devices," said Will Zell, co-founder of Nikola Labs. "Our technology is a breakthrough technology that converts radio frequency energy transmitted by mobile devices into extra battery power for that device.
"We allow you to download power from the air. Our case is embedded with a harvesting antenna that is proprietary that captures wasted RF energy and then takes it through a conversion process to convert it into electricity, then dumps it back into the phone."
The iPhone 6 case can be used to extend the battery life of the smartphone by up to 30%, however it is not able to actually charge the phone.
There are a number of other companies developing similar technology but no commercial product has yet been manufactured.
Nikola Labs hopes to bring its iPhone 6 case to market within the next 12 months through a partnership with Ohio State University. A Kickstarter campaign will be launched in June that will give backers the chance to be early adopters of the case.
The iPhone 6 case is the first product in a range of devices planned by Nikola Labs, ranging from power tools to medical devices.
"Our next product that we're going to bring to market is a wireless charger that will provide near-field and far-field powering solutions to meet you as a consumer where you are, whether that's at home or in your vehicle," Zell said.
"We'll be bringing wireless powering products to the market to give you what our dream is, and that is 100% mobility."