Everything related to computers has improved by leaps and bounds in the last 20 years. Batteries for laptop computers, however, have improved only 10 percent a year during that time.

Laptop users have to rush to plug them into electrical outlets and recharge them after about four hours of use, and at the most inconvenient times.

Power engineers have developed an alternative to the present technology, a fuel cell that recharges a small battery when it gets low. Fuel-cell makers hope to grab some of the $71 billion-a-year worldwide battery market.

Toshiba Corp. promises to begin selling a cellphone powered by a fuel cell before summer. Its direct methanol fuel cell is certified as the smallest in the world. It’s a start toward a laptop fuel cell, says The Wall Street Journal.

Lilliputian Systems, Inc., of Wilmington, Mass., is showing a matchbook-sized ceramic fuel cell for cellphones that is powered by butane, the fuel used in cigarette lighters. It should be ready for sale by the end of this year.

Igo, Inc., of Scottsdale, Ariz., says they will have a fuel cell charger priced at $199 and based on the Lilliputian system. Replacement gas cartridges would cost about $3.99.

That’s a lot more than the $59 it now costs for a backup lithium-ion battery. But the fuel-cell charger will be half the weight and wouldn’t require an electrical outlet.

Users would not have to carry a converter for electrical outlets when traveling overseas.

Lilliputian is developing a fuel-cell system for later delivery that will replace the battery in a laptop and run it for up to 40 hours before the fuel cartridge needs to be replaced.

Gas-powered fuel cells run at high temperatures and must be insulated.