Sony has unveiled a paper-powered battery prototype in Japan.
The technology generates electricity by turning shredded paper into sugar which in turn is used as fuel.
If brought to market, the innovation could allow the public to top up the power of their mobile devices using waste material.
The team behind the project said such bio-batteries are environmentally friendly as they did not use harmful chemicals or metals.
The Japanese electronics giant showed off its invention at the Eco-Products exhibition in Tokyo last week.
Employees invited children to drop piece of paper and cardboard into a liquid made up of water and enzymes, and then to shake it. The equipment was connected to a small fan which began spinning a few minutes later.
Learning from nature
The process works by using the enzyme cellulase to decompose the materials into glucose sugar. These were then combined with oxygen and further enzymes which turned the material into electrons and hydrogen ions.
The electrons were used by the battery to generate electricity. Water and the acid gluconolactone, which is commonly used in cosmetics, were created as by-products.
Researchers involved in the project likened the mechanism to the one used by white ants and termites to digest wood and turn it into energy.
Their work builds on a previous project in which they used fruit juice to power a Walkman music player.
"Using a 'fuel' as simple as old greetings cards - the sort of cards that millions of us will be receiving this Christmas - the bio battery can deliver enough energy to power a small fan," said Yuichi Tokita, senior researcher at Sony's Advanced Material Research Lab.
"Of course, this is still at the very early stages of its development, but when you imagine the possibilities that this technology could deliver, it becomes very exciting indeed."
While the battery is already powerful enough to run basic music players, it is still falls far short of commercially sold batteries.
The environmental campaign group Greenpeace welcomed the development.
"The issue that we always have with battery technology is the toxic chemicals that go into making them and recycling batteries is also complicated," John Sauven, executive director of Greenpeace UK told the BBC.
"Any way to provide a greener technology could be a potential magic bullet. So from that point of view this is interesting, and I think it's fantastic that companies like Sony are looking to make the generation of energy more environmentally friendly."
Sony's engineers are not the only ones exploring the concept of paper-based batteries.
In 2009 a team of Stanford University scientists revealed they were working on a battery created bycoating sheets of paper with ink made of carbon nanotubes and silver nanowires. They said their work might ultimately lead to a device capable of lasting through 40,000 charge-discharge cycles.