Zinc Battery Could Boost Wind Energy and Solar Power

Eos Energy Storge, based in Easton, Penn.,  it is developing a zinc-air battery that can be recharged thousands of times, enough to last 30 years. Zinc-air batteries aren’t new; they’re the button cells in small devices such as hearing aids and watches. They use oxygen that’s abundant in the surround air to react with zinc to produce a charge. Zinc is cheap, and using atmospheric oxygen saves weight and obviates the need for a potentially toxic chemical to drive the reaction.

Ordinarily, though, it’s difficult to build a rechargeable battery this way because a lot of energy is necessary to break down the zinc hydroxide that forms as a result of the reaction in the cell. Eos claims to have a rechargeable version that can go through thousands of cycles — 2,700 in their trials, though the goal is to hit 10,000.

The company says it uses novel chemistry in the electrolyte, avoiding the formation of dendrites (“whiskers”) when the zinc comes out of solution. Eos also says its electrolyte does better at maintaining the shape of the zinc anode.

Analysts say that the company’s technology could show promise for grid storage and electric vehicles. With the right pricing and performance, zinc air batteries may compete not only against other energy storage systems but also grid technologies such as gas turbine plants. The company has an impressive list of product benefits, and investors have been responsive. Eos zinc-air battery is environmentally safe, in that it relies on materials that are nontoxic and nonflammable. Oster has said, "You could flush it down a drain; you could drink it." In an SEC filing, Eos indicated its plans to raise up to $20 million in venture capital.

Eos plans to start manufacturing this year and to work up megawatt-scale systems for grid storage in 2013. The Eos rechargeable zinc-air battery would be sold for $1000 per kilowatt for a six-hour battery, or $160 per kilowatt-hour. Zinc generally enjoys status as one of the world’s most plentiful and inexpensive metals, along with its other qualities as being stable, nontoxic and energy-dense.