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As the EV market continues to gain momentum, some car buyers still have concerns about range and lithium-ion battery safety. To address these valid concerns, a lot of money and time is being spent developing new battery technologies.

In recent years, companies have been investing in an old but improved battery based on aluminum and air, which has the potential to advance the EV industry significantly. The aluminum-air (Al-air) battery appears to be an EV battery game-changer, but is it all hype?

Electric vehicles play a vital role in achieving a net-zero future. However, range anxiety and safety questions over lithium-ion batteries are roadblocks impeding EV market growth. Lithium-ion batteries have been leading the EV revolution, but it's still limited to a 400-mile range, which can pose problems on long road trips.

The hassle of finding a charging station in remote areas and waiting until your EV is charged can put off potential buyers. Other perceived lithium battery issues, such as battery degradation, leakages, and overcharging, don't help its case much either. With all the other battery technology out there, Al-air batteries are getting so much attention because they do not have to be recharged.

The concept of these batteries dates back to the 1960s. But since its electrolyte was dangerously caustic and poisonous, it couldn't be used commercially. Trevor Jackson, an engineering officer in the UK's Royal Navy, started experimenting with the battery in 2001, making it safe to use. Al-air batteries are made of an aluminum alloy plate as the anode, an air cathode, a non-toxic electrolyte like water, and a silver catalyst.

Traditional EV batteries have two electrodes, one cathode and one anode made of different materials, with an electrolyte in between them. When the battery is used, ions flow from the anode through the electrolyte to the cathode. During charging, the ions flow the opposite way back to the anode.

Al-air batteries function similarly to a fuel cell. It uses aluminum at the anode and oxygen at the cathode. The result is a much higher energy density. Around eight to nine times greater than current lithium-ion batteries used in EVs, a substantial power increase. Energy density measures how much energy a battery can store per unit of mass. Power density measures how much instantaneous energy it can deliver per unit of mass.

The anode releases electrons as aluminum oxidizes, while the cathode reduces oxygen to release electrons, thus generating electrical energy. A load can be powered by the electrical current generated by electrons moving through an external circuit. The end result is a white powder that forms on the anode.

Aluminum is the third most commonly found natural resource in the earth's crust and is the most abundant metal on earth, so we will likely never run out. As a result of its softness, aluminum is easy to work with, and it is stable, unlike lithium. Moreover, it's non-toxic. The following are other advantages of Al-air batteries over lithium-ion batteries:

Despite its benefits, there are a few downsides to this battery. First, it has the disadvantage of being a primary battery. Essentially, it cannot be recharged once the battery is discharged or empty. Furthermore, the air inside the battery corrodes the aluminum anode. Therefore, the aluminum plate in the battery needs to be replaced, which can be costly. Additionally, battery production costs can be affected by the fluctuating price of silver the battery contains.

Scientists have been developing better batteries due to the drawbacks of lithium-ion batteries that dominate the EV market. Lithium, nickel, and cobalt used in lithium-ion batteries are rare earth metals only found in certain parts of the world. Currently, EVs account for 6% of vehicles on the road, and mining these metals is well underway; imagine when EV numbers climb to 50% or 80%. Other disadvantages of lithium-ion batteries include the following:

There are factors to keep in mind when considering battery swapping versus recharging. In order to get the same range per charge, a battery pack 1/8 the size of a lithium-ion battery would be needed. Due to the lighter weight of Al-air batteries, EVs will be able to travel further, increasing overall efficiency.

It will also be easier and more convenient to package the battery in a location within the EV that is easily accessible so that it can be easily swapped out when needed. Some companies have estimated an aluminum-air EV battery swap time of just three minutes, getting EV owners back on the road fast.

According to estimates, Al-air batteries last about 5,400 miles. The question is: why would anyone go down this route instead of recharging? With an Al-air-powered EV, you can go much further without finding a charging station. Another reason is that swapping out your depleted Al-air battery for a recycled one is much cheaper than the cost of swapping out a Tesla battery. Since the only replaceable part is the aluminum plates, which can be 100% recycled, you pay for the miles you drive.

It is possible to use Al-air batteries in today's electric vehicles. These batteries will likely increase in popularity as battery-swapping stations become more prevalent. Until then, they could also be used to extend the range of lithium-ion battery EVs, resolving the problem of having to recharge when you aren't able to.

Eventually, EV buyers will have the option of swapping batteries or recharging their vehicles, ultimately creating a more versatile EV market for everyone's benefit. As a result, the transition to a world that is completely based on electric vehicles will continue to accelerate.

Charles is a car and motorcycle enthusiast and retired robotics engineer who served in the US Navy. In retirement, he spends most of his time writing and riding motorcycles.

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