We all know that portable devices in future are pretty certain to be powered by some kind of fuel cell that uses a volatile liquid as a power source in place of a battery, but it's a bit of a surprise to see Toshiba 's latest fuel-cell prototype is to be worn on the head.

The firm's direct methanol fuel cell ( DMFC ) headphones include a tank of flammable methanol on one ear and the player itself, together with a Bluetooth receiver, on the other. Scare-mongering aside, DMFC cells are absolutely safe - the industry wouldn't be pouring the vast funds it has already spent into the technology if they were not.

The methanol reservoir in the Toshiba wireless headphones is charged up with a 5ml squirt from a disposable cartridge, which will give about 10 hours of power. As a backup, there's also a standard lithium-ion battery in the unit, although this isn't likely to be a feature of production models.

Having watched fuel cells progress from huge bricks to tiny demonstration units able to power mobile phones in recent years, we feel confident in predicting that commercial devices will be widespread around 2010, providing fuel distribution and safety issues can be worked out by then of course.