Researchers refine zinc-air batteries with 5x capacity of lithium-ion

“There seems to be a never-ending stream of new battery technologies looking to replace the venerable lithium-ion chemistry,” Brandon Hill reports for HotHardware. “Today, new advances in zinc-air batteries are making them look increasingly more viable as a suitable replacement, with the potential to squeeze five time the charge into a battery comparably sized to its lithium-ion counterpart.”

“The breakthrough comes from researchers working at University of Sydney and the Nanyang Technological University,” Hill reports. “The new method uses a three-stage process that tosses expensive metal catalysts (i.e. platinum, iridium oxide) in favor or cheaper and more common alternatives like cobalt, nickel or iron. And with a more refined manufacturing process, the researchers were able to more intricately control the composition, size and crystallinity of these catalysts to build robust rechargeable zinc-air batteries.”

Read more in the full article here.

MacDailyNews Take: Every battery story starts out so promising and then ends in exactly the same way: Wah-wah, maybe someday.

As always, here’s hoping for a battery breakthrough!

New battery technology suitable for future iPhone promises tripled power density, full charge in minutes – March 6, 2017
94-year-old inventor of li-ion battery unveils solid-state battery breakthrough – March 1, 2017


    1. As noted in the summary, the new form of rechargeable zinc is great for allowing use of less expensive materials.

      Now comes the years of hard work to prove out all of the needed reliability, safety, consistency & production machinery, plus new software algorithms to be used to monitor and control the charge & discharge cycles of such batteries.

      If they indeed allow much higher energy densities, then the zinc-air batteries will also have an even higher potential for “explosive” discharge due to damage.

      Lots of work is yet to be done to get to a proven successful safe battery. I hope they make it work.

      1. Explosive discharge is rare in zinc-air batteries due to charge being created by oxidation. Usually by pulling in O2 from the air (hence the name). The only way I could imagine an explosive charge being generated is if the battery were somehow thrown into a high O2 environment and then broken.

      1. The ‘recharging’ process is actually more like recycling the zinc to use in a new battery than the conventional plug in the recharge unit since you have to separate the zinc from the O2 it absorbed.

  1. Zinc – air primary ( non-rechargable ) batteries have been widely used for decades and are most commonly used in hearing aids, where very tiny dimensions and very long periods of operation ( about a week of continuous operation ) are required. They are also used in specialised film cameras. They are easily identified because the user has to remove a little tab to allow the air to enter the battery before it starts working. Obviously that sort of battery would not power a vehicle.

    Zinc-air secondary ( rechargeable ) batteries have been around for a while in laboratories and offer tremendous power to weight ratio, use commonly available materials, are intrinsically pretty safe and are very cheap to make.

    As Xennex has pointed out, the tricky aspect is recharging them because the oxygen in air reacts with the zinc to produce hydroxyl, which then reacts with the zinc to produce an electric current. The problem so far has been that once it has reacted, the zinc can’t be used again and in laboratories, that has generally involved replacing the zinc, or alternatively using exotic catalysts made from expensive materials such as platinum and iridium oxide

    What the researchers in Sydney have done is to create new catalysts based on commonly found elements such as iron, cobalt and nickel. A low cost electrolyte would make the battery significantly cheaper

    I have read about experiments decades ago where researchers built zinc air cells weighing 50 lbs to power vehicles for extended durations compared to present day technology, but the problem was recharging them. However there are a number of companies working on this technology and solutions involving zinc-air secondary cells are already in use in Israel for buses, but they use mechanical recharging ( the cassette containg the zinc is replaced ). However the buses have a range of 230 km and use a combination of zinc-air and super capacitors, which offer zero emission, silent and of course makes them less dependent on imported fossil fuels.

    There are other companies making grid storage batteries using zinc-air with capacities of around 1 MW and with running costs lower than using natural gas generators used for surge power.

    With mechanical recharging ( replacing the zinc ) energy densities of around 220 Wh/kg are possible, at the moment, electrical recharging ( using electricity to restore the chemistry ) offers about 150 Wh/kg, but is improving.

    There is another interesting variant of zinc-air cells which I have heard speculation of in connection with an Apple car. You can have batteries using a slurry of zinc particles and electrolyte which is pumped over a metal bed to generate electricity. The battery operates until all the zinc particles have reacted, at which time the user would connect to a roadside pump which extracts the spent ‘fuel’ and replaces it with new. Does that sound like a familiar operation? It takes about ten minutes.

    There are other issues regarding zinc- air. One aspect is both an advantage and a disadvantage. Zinc-air can’t provide massive surges of power so in order to get stunning acceleration, a super-capacitor would provide briefly kick in to help out. The reason why zinc-air can’t supply huge surges is that the generating process shuts down when short circuited, which makes it inherently safe in an accident. The battery can also be shut down by turning off the valve allowing the air in – think of it as an ignition switch. Another useful aspect of a pumped slurry battery is that the slurry can be passed through a cooling device as part of the normal operation, so no additional cooling system would be needed like with other electrically powered vehicles which need to actively cool the battery.

    At the moment, there are issues with the operational life being around three years, which is likely to improve with further development, but on the other hand, the battery is relatively cheap to manufacture and the cost might be comparable to paying for a 24,000 mile service on a petrol car.

    If Apple is working on an electrically powered car, my guess is that they will not employ conventional Li oN batteries, but will favour either fuel cells or zinc air cells, most likely using pumped electrolyte.

  2. I think the impetus is a greatly different this time what with cars in many countries having to be non IC within 20 odd years and of course the Smartphone, Smartwatch, Smarteverything revolution that’s only just getting into its second decade. I would be surprised if there were not great leaps forward within 10 years which combined with ultra quick recharging will totally change the dynamic.

    1. A solution which at least one group is reportedly exploring is to use an advanced pumped electrolyte system. The idea being that a user can slowly recharge the electrolyte at home by recharging from a standard mains socket, but when making long journeys, could call in at a roadside pump to have the used electrolyte rapidly replaced with fresh, fully charged electrolyte and be on their way within minutes. No need for a special mains supply to a rapid charger at home because the range could be such that a full charge lasts for a week’s worth of local driving, therefore leisurely overnight top-ups are fine.

      It doesn’t need much imagination to work out the appeal of a system which allows most users to slowly top up their tank at home for most of the time, but still able to use rapid roadside top-ups for long distance trips. If anybody solves this particular challenge, it will present a formidable challenge to IC engines

      There is also research being carried out into optimising zinc-air cells optimised for trucks and semis. As truck drivers take regular breaks and generally stop at truck stops, it wouldn’t be difficult to set up the infrastructure to either swap zinc-air cartridges, or pump in refreshed electrolyte while the driver takes a short break.

      Some trucking operations involve relatively short, repetitive runs ( such as between freight terminals and distribution centres ) and the recharging could be done at the depot overnight. Tesla will soon launch electrically powered trucks. It’s a market segment which could experience a period of remarkable change once somebody gets the technology properly sorted,

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