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| Lithium Air Batteries with "2D materials" could offer 800 km range
Electric cars may clock up to 800 km on single charge !
WASHINGTON: Scientists say they have developed several two-dimensional (2D) materials which may enable electric vehicles to clock up to 800 kilometres on a single charge. Quote:
Lithium-air batteries, which are still in the experimental stages of development, can store 10 times more energy than currently used lithium-ion batteries, and they are much lighter, said researchers from the University of Illinois at Chicago (UIC).
Lithium-air batteries could be even more efficient and provide more charge with the incorporation of advanced catalysts made from two-dimensional materials, they said.
In the research published in ‘Advanced Materials’, researchers synthesised several 2D materials that can serve as catalysts. A number of their 2D materials, when incorporated into experimental lithium-air batteries as the catalyst, enabled the battery to hold up to 10 times more energy than lithium-air batteries containing traditional catalysts.
| Source Quote:
https://Youtu.be/AGy3BddUvC8
Batteries of the Future
According to University Of Illinois At Chicago researchers, lithium-air batteries could be even more efficient and provide more charge with the incorporation of advanced catalysts made from two-dimensional materials.
Catalysts help increase the rate of chemical reactions inside batteries, and depending on the type of material from which the catalyst is made, they can help significantly boost the ability of the battery to hold and provide energy.
“We are going to need very-high-energy-density batteries to power new advanced technologies that are incorporated into phones, laptops and especially electric vehicles,” said researcher Amin Salehi-Khojin.
His team synthesised several 2D materials that can serve as catalysts. A number of their 2D materials, when incorporated into experimental lithium-air batteries as the catalyst, enabled the battery to hold up to 10 times more energy than lithium-air batteries containing traditional catalysts.
“Currently, electric vehicles average about 100 miles per charge, but with the incorporation of 2D catalysts into lithium-air batteries, we could provide closer to 400 to 500 miles per charge, which would be a real game-changer,” Salehi-Khojin said. “This would be a huge breakthrough in energy storage.”
15 different types of 2D transition metal dichalcogenides or TMDCs were synthesised. TMDCs are unique compounds because they have high electronic conductivity and fast electron transfer that can be used to participate in reactions with other materials, such as the reactions that take place inside batteries during charging and discharging.
The investigators experimentally studied the performance of 15 TMDCs as catalysts in an electrochemical system mimicking a lithium-air battery.
“In their 2D form, these TMDCs have much better electronic properties and greater reactive surface area to participate in electrochemical reactions within a battery while their structure remains stable,” said Leily Majidi first author of the paper.
“Reaction rates are much higher with these materials compared to conventional catalysts used such as gold or platinum.”
One of the reasons the 2D TDMCs performed so well is because they help speed both charging and discharging reactions occurring in lithium-air batteries.
“This would be what is known as bi-functionality of the catalyst,” Salehi-Khojin said.
The 2D materials also synergise with the electrolyte – the material through which ions move during charge and discharge.
“The 2D TDMCs and the ionic liquid electrolyte that we used acts as a co-catalyst system that helps the electrons transfer faster, leading to faster charges and more efficient storage and discharge of energy,” he said.
“These new materials represent a new avenue that can take batteries to the next level; we just need to develop ways to produce and tune them more efficiently and in larger scales.”
| Source
Lithium-Air: A Battery Breakthrough Explained Quote:
In the quest for smaller, longer-lasting, more powerful batteries, scientists have tried many alternative approaches to battery chemistry. One may have just produced the breakthrough we’re waiting for.
The urban legend is that there was a small leak in a battery cell that chemist K M Abraham was testing in his laboratory in 1995, which provided the cell with a far higher energy content than expected. Rather than try to fix the leak, Abraham investigated and discovered the first rechargeable lithium-air (Li-air) battery. So far this discovery hasn’t led to any technically viable products, but a paper published in Science from a University of Cambridge research group may be about to change that.
In 2008, Tesla amazed industry watchers with its bold, electric Roadster car that ran on off-the-shelf lithium-ion (Li-ion) batteries, the sort that power everything from smartphones to laptops to cameras and toys. Since then, not only has the market for electric vehicles quickly grown, but so has the average range of the batteries that power them. However that growth needs to accelerate: from 1994 it took 20 years to triple the energy content of a typical Li-ion battery.
The new research, led by professors Gunwoo Kim and Clare Grey, experimented with Li-air cells that use only an electron conductor, such as lightweight, porous carbon, instead of a metal-oxide typically used in a Li-ion battery. Practically speaking, this saves a lot of weight, but brings its own difficulties.
How Lithium-Air Batteries Work
A Li-air cell creates voltage from the availability of oxygen molecules (O2) at the positive electrode. O2 reacts with the positively charged lithium ions to form lithium peroxide (Li2O2) and generate electric energy. Electrons are drawn out of the electrode and such a battery is empty (discharged) if no more Li2O2 can be formed.
However, Li2O2 is a very bad electron conductor. If deposits of Li2O2 grow on the electrode surface that supplies the electrons for the reaction, it dampens and eventually kills off the reaction, and therefore the battery’s power. This problem can be overcome if the reaction product (lithium peroxide in this case) is stored close to the electrode but does not coat it.
The Cambridge researchers found a recipe that does exactly that – using a standard electrolyte mixture and adding lithium iodide (LI) as an additive. The team’s experiment also include a rather spongy, fluffy electrode made of many thin layers of graphene filled with large pores. The last important ingredient is a small amount of water.
With this combination of chemicals, the reaction as the battery discharges does not form the Li2O2 that would gunge up the electrode’s conducting surface (see image below, left hand side). Instead it incorporates hydrogen stripped from the water (H2O) to form lithium hydroxide (LiOH) crystals. These crystals fill the size of the pores in the fluffy carbon electrode, but crucially they don’t coat and block the vital carbon surface that is generating the supply of voltage (right hand side). So the presence of lithium iodide as “facilitator” (though its exact role is not yet clear) and water as co-reactant in the process boosts the Li-air battery’s capacity.
How Will Li-Air Change Things?
This process which ensures the electrode surface is kept clear is essential to boost battery capacity. However, the drawback is that the same lack of electrical contact between the electrode and the discharge product that boosts its capacity should in principle make it difficult to recharge.
Again, it turns out the lithium iodide additive is the missing ingredient needed: at the electrode, negatively charged iodide ions are converted into I3 (triiodide) ions (see picture, right-hand side). These combine with the LiOH crystals and dissolve, allowing for a complete recharge by clearing the pores.
In fact this mechanism is even more effective than the recharge of Li2O2 attached to the electrode surface. Since the electrons do not need to travel through a Li2O2 layer, less voltage is required to recharge a Li-air battery with the iodine additive than without it. So less energy is needed to recharge the battery, which would make an electric car running on such a Li-air battery more energy efficient. The study’s authors present data that are approaching an energy efficiency of around 90% – which brings this new battery technology close to that of conventional Li-ion batteries.
Their findings reveal a promising way forward for Li-air technology, at a time when many other research groups have given up. As more researchers return to the subject following this breakthrough, perhaps a commercial Li-air battery will finally become reality.
| Source
And Now there is talk of Zinc Air Batteries to replace Lithium
Patrick Soon-Shiong on 'holy grail' zinc-air battery
Patrick Soon-Shiong, NantKwest CEO, chairman of NantEnergy and Los Angeles Times owner, discusses NantEnergy's new zinc-air rechargeable battery system that he hopes will eventually replace the lithium battery.
These Battery developments will influence the automotive scene worldwide.
Just like how the cellphone/mobile revolution took the Indian market by storm, Similarly the Electric Car revolution could influence the Indian Market on an unprecedented scale and much sooner than most people will anticipate.
Although it will depend how soon the Indian Govt. and Major Car manufacturers develop the basic infrastructure needed for Fast charging.
Last edited by JS Kwt : 12th January 2019 at 17:14.
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12th January 2019, 16:52
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