Zinc8 engineer working in the company’s research facility in Vancouver, BC. (Courtesy images: Zinc8)
George Harvey
There are many kinds of electric batteries. Given the needs for energy storage that exist today and will predictably come up in the future, it should not be at all surprising that many battery designs are being developed. Zinc8, based in Vancouver, British Columbia, has a unique approach to the problem, and we would do well to understand it.
Electricity can be generated when the metal zinc is oxidized. Batteries that use this have been around for a long time. The chemistry is commonly used for the button batteries that power hearing aids. It is usually used as a primary zinc-air battery, meaning that it cannot be recharged, but secondary battery chemistry, for rechargeable batteries, has been around for a while, though not widely used.
Now, we might do well to understand a different kind of battery, the flow battery. Most flow batteries have electrolytes that are stored in tanks and flow past each other in a vessel, usually separated by a membrane. Flow batteries have a lot of advantages, not the least of which is that they can be configured for a given system. If more energy is needed over a longer period of time, larger tanks can be used. If more power is needed, a larger reactor unit can be used with more membrane area. Flow batteries can be designed to be easily rechargeable, and offer promise for grid energy storage.
What Zinc8 has done is to combine these two ideas in a quite novel way, producing what it calls a “Zinc-Air Energy Storage System.” This is a bit like a flow battery, in its way, and it is certainly a zinc-air battery. But that combination is the very surprising thing that the people at Zinc8 have figured out.
One thing to understand is that the zinc in Zinc8’s battery is in the form of particles about the size of particles of fine sand. In that form, they can be moved about in a fluid, which in this case is a solution of potassium hydroxide. When electricity is needed, zinc particles are gradually moved into a chamber where they can react with atmospheric oxygen, and this reaction produces electricity. It also produces zinc oxide (technically zincate), which is moved to a tank for storage.
When the demand for electricity drops and it is possible to recharge the battery, the zinc oxide is given a charge that causes it to give up its oxygen. This returns the particles to their original state, as tiny grains of zinc metal, and it is moved back to the zinc storage container.
Unlike lithium-ion technology, which requires new stacks in order to scale, Zinc8 has decoupled the linkage between energy and power. This means that scaling Zinc8’s technology can be accomplished by simply increasing the size of the fuel tank and quantity of recharged zinc fuel.
There are certain things about this that are really beautiful. One thing is that zinc is a common element. It is easily available in nature. Neither the metal nor its oxide is particularly toxic to human beings, though the metal is toxic to some lower life forms. In fact, because zinc, as an element, is a requirement for good health, zinc oxide may be added to breakfast cereal. (Please note that high doses of zinc, such as would result from swallowing the metal, are toxic. Also, bringing zinc to high temperatures, which results from trying to weld galvanized iron or trying to use the galvanized pipe on wood stoves, can cause severe health issues. These are not issues with zinc-air batteries, however.)
Zinc8 batteries also have some special characteristics. Zinc8 claims that they do not lose capacity with use or time. They can be fully discharged without damage. They are based on stable and well-developed supply chains. They are safe, non-flammable and non-toxic. And they can be built at a very low cost, compared to other batteries. The smallest sizes Zinc8 plans to produce at present appear to be about what would be needed for a small group of households or a small commercial or industrial site, and the largest might be suitable for electric utility use.
Clearly, batteries of the type Zinc8 has developed could be expected to sell well. Filling that demand will mean establishing manufacturing facilities. And since new factories in an area will mean new jobs, there are people who hope to attract Zinc8 to the places where they live to build a plant.
In July, it was announced that Senator Schumer of New York has been in talks with Zinc8 to build a factory in Ulster, New York, which is about 55 miles south of Albany on the Hudson River. The site that would be used for the new factory was formerly used as a dumping ground and is contaminated with asbestos. Cleaning it up and using it for a factory for manufacture of non-toxic batteries would be a win all the way around.
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