TOKYO (AP) _ Toyota Motor Corp. displayed its new experimental fuel-cell vehicle, which has an additional battery for more efficient driving and storing of energy.

The Japanese automaker's FCHV-3, on public display Thursday at a symposium on fuel cell technology, is similar to Toyota's hybrid Prius car already on the market.

The Prius switches back and forth between an electric motor and a gas engine to maximize efficiency and store energy created by braking.

The fuel cell hybrid switches back and forth between the fuel cell and battery-operated electric motor. It runs on pure hydrogen stored inside the car in an alloy _ a mixture of metals _ that absorbs hydrogen.

All the world's major automakers are working on fuel-cell cars, which are super-clean because they run on electricity produced by combining hydrogen and oxygen. The byproduct is water vapor, instead of noxious fumes.

The automakers are working on fuel-cell cars that run on different types of fuel besides pure hydrogen, such as methanol, a liquid that contains hydrogen. The cars use oxygen from the air.

``The fuel question is a crucial one for the development of fuel cells,'' said Johannes Ebner, head of DaimlerChrysler's fuel cell project, who was at the symposium in Tokyo.

Fueling stations for hydrogen will have to become prevalent like gas stations if fuel cells are to become a real option for drivers. And compressed hydrogen is not as easy to transport on roads as gasoline, Ebner said.

General Motors Corp., which is working with Toyota on some fuel cell vehicles, is developing a fuel similar to gasoline called ``clean hydrocarbon fuel'' that can be dispensed at gas stations for regular cars but can also be used for fuel-cells.

Clean hydrocarbon fuel can be an ``interim solution,'' said GM official George Hansen, while refusing to say what exact components would make up that fuel.

The fuel is made from crude oil or natural gas and is expected to become prevalent in the next decade _ years ahead of the widespread use of hydrogen, according to Toyota.