Flexibile, biodegradable batteries could become a reality after a team of scientists at the Rensselaer Polytechnic Institute and MIT developed a new material to overcome one significant challenge to battery technology.

Traditionally, batteries require two charge-holding electrode layers and an insulating layer in between them but the researchers have now developed a new material based on carbon nanotubes that doesn't require such layers.

They grew the nanotubes in the labs and put cellulose paper into the tiny gaps between the tubes. The paper acts as an insulator, and allowed the scientists to develop flexible battery cells.

The researchers say it's possible to build batteries in different shapes for different uses using the technology.

"By putting a drop of electrolyte on a single sheet and then putting a metal foil consisting of lithium and aluminium on each side, a lithium ion battery is formed. This paper device had a respectable 110mAh/g capacity, and the researchers indicate that small prototypes could already power small mechanical devices like fans," Ars Technica explains.