WASHINGTON — You recline your chair, close your eyes, put on your headphones. And then it happens.

The batteries die. Again.

Enter Oxyride, Panasonic's new disposable battery. The maker says it's the greatest thing since, well, the alkaline battery, for MP3 players, LED flashlights, portable TVs, Game Boys, digital cameras and other devices that use a lot of power fast.

Panasonic's suggested retail price for a four-pack of Oxyride Extreme Power batteries is $3.99.

The battery, arriving at stores nationwide, lasts up to twice as long as an alkaline battery, according to Panasonic. Company officials and competitors agree that it isn't as economical or as environmentally friendly as rechargeable batteries, however.

Brian Kimberlin, the director of marketing for Secaucus, N.J.-based Panasonic Battery Group, said it is high time to replace the 40-year-old alkaline battery.

"What we heard from the consumer ... was that there are so many electronics being introduced each year, and they couldn't understand why it took so long to get a better battery," he said.

The Oxyride yields 1.7 volts of electric power, compared with 1.5 volts for the alkaline battery, thanks to a new and repackaged form of oxy-nickel hydroxide, which releases more power.

The secret is using finer and more tightly packed particles of the substances that form the surface of the electrode, the part of the battery that collects and conducts current. The greater the surface area of those substances — oxy-nickel hydroxide, manganese oxide and graphite — the greater the current generated.

Kimberlin said the new battery could take at least twice as many photos on a digital camera, speed up the flash-recovery time on film cameras and propel remote-controlled toy cars faster. Competitors aren't so sure, and even Panasonic admits the Oxyride won't work better than an alkaline battery on radios, remote controls, flashlights and toys that don't need the extra power.