Three times the power for half the price. That's the promise of new rechargeable Zinc-air batteries with three times the (mass) energy density of Lithium ion batteries. The new technology looks like a big step forward for power storage for uses for electronic applications such as laptop batteries. Moreover, it has potential to extend the time before recharge of electric cars and off the grid solar systems. Zn-air batteries were previously not rechargeable because the electrodes tended to dry out or short out by the formation of elongated crystals. The new technology uses multiple engineered layers to contain and control the electrochemical reaction so it can go through over 100 charge/discharge cycles. How much over 100 cycles is not yet shown.
By FishOutofWater
Zn-Air has the potential of storing far more power for large scale applications then existing batteries. The primary limitation to the new technology is the limited rate of power transfer. For electric cars, Zn-Air batteries will need to be combined with batteries that recharge and discharge more quickly.
A Swiss company says it has developed rechargeable zinc-air batteries that can store three times the energy of lithium ion batteries, by volume, while costing only half as much. ReVolt, of Staefa, Switzerland, plans to sell small "button cell" batteries for hearing aids starting next year and to incorporate its technology into ever larger batteries, introducing cell-phone and electric bicycle batteries in the next few years. It is also starting to develop large-format batteries for electric vehicles.
By FishOutofWater
Zinc is inexpensive, widely available in large quantities, and doesn't tend to catch fire in any form, unlike Li-ion batteries. Concerns about limited supplies of lithium will be relieved by transitioning to zinc-air batteries.
Moreover, it may be possible to use zinc metal powder to make a fuel cell like battery for large scale applications.
For electric vehicles, ReVolt is developing a novel battery structure that resembles that of a fuel cell. Its first batteries use two flat electrodes, which are comparable in size. In the new batteries, one electrode will be a liquid--a zinc slurry. The air electrodes will be in the form of tubes. To generate electricity, the zinc slurry, which is stored in one compartment in the battery, is pumped through the tubes where it's oxidized, forming zinc oxide and releasing electrons. The zinc oxide then accumulates in another compartment in the battery. During recharging, the zinc oxide flows back through the air electrode, where it releases the oxygen, forming zinc again.
In the company's planned vehicle battery, the amount of zinc slurry can be much greater than the amount of material in the air electrode, increasing energy density. Indeed, the system would be like a fuel-cell system or a conventional engine, in that the zinc slurry would essentially act as a fuel--pumping through the air electrode like the hydrogen in a fuel cell or the gasoline in a combustion engine. McDougall says the batteries could also last longer--from 2,000 to 10,000 cycles. And, if one part fails--such as the air electrode--it could be replaced, eliminating the need to buy a whole new battery.
An electric car with three times the range of existing electric cars could replace almost every gasoline powered commuter vehicle.
And solar power is getting cheaper and more practical every day.
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