Toshiba has developed what it claims is the world's smallest direct methanol fuel cell (DMFC), designed to be integrated into devices as small as digital audio players and wireless headsets for mobile phones.

The Japanese electronics giant said that the size advantage of the slim prototype DMFC would mean greater design freedom for developers of handheld electronic devices.

The DMFC measures 22mm x 56mm x 4.5mm with a maximum 9.1mm for the central fuel tank, and weighs just 8.5g. According to Toshiba it is efficient enough to power an MP3 music player for as long as 20 hours on a single 2cc charge of highly concentrated methanol.

"The cumulative result of these advances is the world's smallest 100mW fuel cell; a more compact, more efficient DMFC that outperforms its predecessors by a factor of five in terms of power output," said Toshiba in a statement.