Vodafone has announced a line of sleeping bags and clothing with the ability to charge a smartphone, Digital Spy said.

The Power Shorts and Recharge Sleeping Bag are made with Smart Fabric that draws on kinetic and thermal energy into a 'Power Pocket' to power up the user's device.

One day's walking in the Power Shorts equates to four hours of battery life, while a full night's sleep in the Sleeping Bag will add 11 hours to a phone's battery.

"We are exploring two specific technologies to charge the Power Pocket: thermoelectrics and kinetic energy harvesting," said Professor Stephen Beeb, whose team at the University of Southampton pioneered the technology.

"Both represent cutting-edge research around smart fabrics and we are looking to integrate these into consumer products, in this case, a sleeping bag and a pair of denim shorts."

The Power Shorts and Recharge Sleeping Bag are aimed at festivalgoers, and will launch in time for the Isle of Wight Festival on June 13.