Mobile phones could soon run for months rather than days between charges, after scientists discovered how to make them work more efficiently.
A team of electrical engineers at Illinois University in the US believe their method will enable mobiles and laptops to run for up to 100 times longer between charges.
It focuses on changing the way a device's digital memory works, as this consumes much of the charge.
At the moment mobile phone memories contain thin metal wires. Every time information is accessed, electricity is passed through them to retrieve the data.
The electrical engineers thought that if the size of the components used to store and retrieve the information could be reduced, so could the amount of electricity.
They have discovered a way of using carbon nanotubes - tiny tubes 10,000 times thinner than a human hair - instead.
Feng Xiong, a graduate student on the team who was lead author on a paper, to be published in the journal Science, explained: "The energy consumption is essentially scaled with the volume of the memory bit.
"By using nanoscale contacts, we are able to achieve much smaller power consumption."
Prof Eric Pop, who led the project, said: "I think anyone who is dealing with a lot of chargers and plugging things in every night can relate to wanting a cell phone or laptop whose batteries can last for weeks or months."
He thought that the method could improve a mobile phone's efficiency so much that they could be made to run simply by harvesting heat, kinetic energy or solar energy.