Green Tech

A California start-up says next year it will introduce a BlackBerry-size box that uses zinc as a fuel to charge electronic gadgets, a move that some people hope is a small step toward a broad zinc-based energy industry.

Three-year-old Power Air was formed to commercialize zinc-air fuel cell technology developed at the Lawrence Livermore National Laboratory. The core technology--an alternative to lithium-ion batteries or hydrogen fuel cells--creates an electrical current by exposing a zinc solution to the oxygen in air.

The long-term plan for Power Air is to build backup generators and mobile power sources for boats or vehicles.

Its first commercial product, though, is portable power supplies for cell phones, iPhones, and other consumer electronics. It plans to introduce the product line, called ZAFC Powerpacks, at the Consumer Electronics Show in January, according to Power Air CEO Don Ceci.

Power Air has developed a zinc-air fuel cell, which it says offers advantages over hydrogen fuel cells and lithium-ion batteries. Click diagram for larger version.

(Credit: Power Air)

The power packs are aimed at people who need auxiliary power, such as the businessperson or student who wants to extend power of a cell phone for another hour at the end of the day.

There are other options for portable power, based on alternative fuels.

Medis earlier this year released a liquid fuel cell for gadgets, while another start-up, M2E Power, is developing a battery pack that is recharged by motion. Meanwhile, large consumer electronics companies are developing fuel cells that use the liquid fuel methanol.

Power Air is pursuing a similar tack but is using a different chemistry to make electricity. In a zinc-air battery or fuel cell, zinc powder or pellets are fed into an electrolyte solution. Exposing the solution to air causes a chemical reaction that starts the flow of electrons--what most people know as electricity.

In the case of the ZAFC Powerpack, the consumer would open a lid on the pack to get the current flowing. Inside is a gel that contains the zinc powder and electrolyte.

Some energy experts argue that zinc-air technology has many advantages over existing battery technologies and that zinc is a better energy source than, say, lithium.

Zinc is already used in many products, including batteries, and it is abundant. It has high energy density, which means that batteries or fuel cells can pack more power into a given space compared to other batteries based on other chemistries, Ceci said. It's also safe, and the material can be recycled, he said.

"Really, what the world needs is a sustainable fuel, and zinc has the potential to be that sustainable fuel," Ceci said.

Hearing aids already use zinc-air batteries. But one of the biggest technical challenges to broader energy use is making a zinc-air energy supply that can be recharged hundreds of times like other batteries.

Power Air's goal is to improve the lifetime operation of its zinc-air fuel cells in the next two years so that it can be used for backup power supplies, such as indoor generators, Ceci said.

Gadget charger
Because electronic gadgets don't have the same requirements as generators, the company's first product will be auxiliary power packs, which are a $150 million-per-year market, Ceci said.

Power Air's zinc-air power supply will cost about $20 and include adapters for common devices, such as iPhones and 3G mobile phones. Consumers will be able to return the fuel cartridges for recycling and purchase new ones for between $10 and $20, Ceci said.

The company now has a prototype zinc-air power pack that is expected to store between 15 watt-hours and 20 watt-hours, the equivalent of between 7 and 10 full charges for a device.

"Button cell" made out of zinc.

(Credit: American Zinc Association)

Planned lithium-ion versions of Power Air's battery pack, also due early next year, will be more expensive but can be recharged. A 7-watt-hour version will cost about $40 and be able to recharge a phone between 1,000 and 1,500 times.

The company hopes to have the power packs and cartridges available in retail stores and catalogs. The plan is that a consumer will be able to send back a spent charge pack. The gel inside can be recycled through well understood processes and the zinc reused, Ceci said.

Zinc economy?
Lithium-ion batteries have become the preferred chemistry for millions of consumer electronics and for a planned wave of battery-powered cars, such as the Chevy Volt and future versions of the Toyota Prius.

But there are some concerns that the huge demand from electric cars and electronics will strain the global supply of lithium, potentially leading to higher prices and environmental degradation where lithium is extracted.

Ceci said that Power Air has been in discussions with global electronics manufacturers, which have shown interest in zinc-air power supplies.

Meanwhile, Japanese newspaper Nikkan Kogyo earlier this year reported that Toyota is researching zinc-air battery technology as a successor to lithium-ion. The planned commercialization of the zinc-air batteries was said to be 2020.

There are other zinc energy companies, some of which formed a consortium called the Zinc Energy Storage Technology Consortium (ZESTec).