OK, I'll admit, this isn't really a new idea. A lot of hearing aid and medical-use batteries are powered by zinc, air, and water which combine to make Zinc Oxide, giving off electrons in the process. Called ZOE batteries (Zinc Oxygen Energy) or ZAFC (Zinc Air Fuel Cell), the technology is common on a small scale, but until now was not thought to be possible on a larger scale. Like, say, the size of an electric car.
A Hong Kong Company called Advanced Power and Energy Transportation (APET) has a prototype car they're calling the Salamander. It's running on a combination of Nickel Metal Hydride (NiMH) and ZOE batteries. They plan to get rid of the NiMH batteries soon and go all-ZOE instead.
I keep abreast of the latest with electric vehicles (EVs) for my writing over at Zoomilife and out of my own general interest and saw this at one of my favorite sites Gas2.0. While intrigued with the car idea, I was even more interested in the battery technology itself–for a lot of reasons, which I'll show you here.
The common problems with scaling up a Zinc battery have always been their relative weight, the high cost of materials, and the fact that they can't be recharged in the traditional way. So up to now the only large-scale Zinc batteries have been as experimental military, industrial, and other uses. APET seems to have solved these problems with their ZOE system.
Rethinking the way these batteries are normally built, APET redesigned them to lower the weight, effectively doubling the watt hours per kilogram (Wh/kg) versus a same-sized lithium polymer solution and four times what you get out of a NiMH of the same size.
To cut the cost, which was part of what changed the weight issue as well, the engineers reduced the materials used and simplified the process to make them, which reduced the battery's cost to about 1/10 of li-po and 1/5 of NiMH.
Then they designed them to be either totally recyclable (battery casing can be re-used and zinc oxide can be re-constituted). So the battery, rather than being thrown away, can be emptied of its zinc oxide (the byproduct of the process) and have that replaced so it's re-used. The zinc oxide can either be used in other applications or heated to high temperature, which burns off the oxygen content and leaves zinc again.
Burning the zinc oxide has some obvious drawbacks until you consider APET's solution for that: building solar furnaces. That might actually work, since the huge amount of heat required could be had in this regard basically free of charge.
What all of this means is that APET has build a battery cell whose total weight is 630 grams. These have 210 grams of Zinc, 160 grams of electrolyte, and 260 grams in casing and electronics. This cell produces 1.1V nominal at 20A with a total capacity of 140 amp hours. That's 154Wh, giving it 244Wh/kg. It can be tailored to just about any temperature use range by changing the composition of the electrolyte and the company is currently working in a range of -20°C to 60ºC.
These are impressive numbers for battery tech that can be scaled large enough for a car. One of the largest drawbacks to current battery EV technology is weight:range comparisons. To get the best weight to range optimum, you either pay a high premium for batteries or you get a car that's too heavy to be efficient. It's for this reason that most large automotive companies are putting so much R&D into hydrogen fuel-cell technology.
If this APET ZOE battery works, though, it could be an answer for some of those companies like Nissan who're aiming straight at the battery-electric market. We may know as early as next year, since the Salamander is an Automove X-Prize entrant as a 4-door coupe.
