The two phones were co-developed with Toshiba and Hitachi The Toshiba handset is a modified A5509T, which has a direct methanol fuel cell built on the back, above a regular internal Lithium-ion battery.
The fuel cell's refillable 7cc tank contains enough concentrated methanol - it's in a 99.5 per cent solution - to provide 2.5 times the operational duration of the regular battery, KDDI claimed.
A Hitachi W32H handset has been similarly augmented, though this time the fuel cell is mounted on the display-side of the clamshell handset. Hitachi's fuel-cell system also uses methanol, though the concentration is no more than 60 per cent, and its reservoir can hold only 3cc of the liquid.