The Tokyo-based company said it is testing prototypes of what it calls a direct methanol fuel cell, or DMFC. The cartridge contains a passive supply of the alternative fuel in highly concentrated form, which produces electricity by causing a chemical reaction.
After three years of delays, Toshiba said commercial products based on the technology are expected to appear on store shelves in 2007.
Fuel cells usually use alcohol or hydrogen as fuel and can offer five to 10 times the power per unit weight as lithium-ion batteries.
Toshiba is developing two versions of the fuel cell. One is formatted for flash-based digital music players such as Apple Computer's iPod Shuffle. The other is for digital music players based on hard disk drives (HDD), such as the iPod Photo or Toshiba's Gigabeat player.
Toshiba said its 100-milliwatt version is similar in shape and size to a pack of gum and can power a flash-based player for approximately 35 hours on a single 3.5-milliliter charge.
A 300-milliwatt version of the fuel cell is about the size of a pack of playing cards and has enough juice to power an HDD-based player for approximately 60 hours on a single 10-milliliter charge.
Toshiba did not say if the fuel cells would ultimately be designed to allow consumers to refill, as shown in the accompanying image, or if the cells would be sold as a disposable product only. That may depend in part on the findings of the International Electrotechnical Commission, which is reviewing a draft of safety standards based on international standardization specifications for micro fuel cells.
The two types of MP3 player and their methanol cartridges are expected to go on display at the Ceatec Japan 2005 trade show in October.
Other technology companies are working on similar devices to enhance the battery life of mobile devices such as notebooks, MP3 players and mobile phones.
IBM and Sanyo Electric have developed a prototype of a methanol-based fuel cell system for ThinkPad notebooks. The fuel cell can be charged by means of an auxiliary docking station, which also provides an alternative power supply.
Fuel cell developer UltraCell has come up with a for portable electronic devices that it says has twice the energy density of lithium batteries.
Medis makes a disposable fuel cell, called Power Pack, that provides an additional 20 hours of charge time for cell phones, digital cameras, personal digital assistants and MP3 players.
Compact Power Systems makes two battery/charger products specifically for the iPod. Cellboost connects with the 30-pin iPod and iPod Mini for an additional 8 hours of playing time. The company's iRecharge product is a rechargeable lithium-ion battery pack that can give you an additional 12 hours of charge time for the standard iPod and as much as 40 hours of extra charge time for the iPod Shuffle.