BBC News: A new manufacturing method for lithium-ion batteries could lead to smaller, lighter batteries that can be charged in just seconds.
Batteries that discharge just as quickly would be useful for electric and hybrid cars, where a quick jolt of charge is needed for acceleration.
The approach only requires simple changes to the production process of a well-known material.
The new research is reported in the scientific journal Nature. Because of the electronic punch that they pack, gram for gram, lithium-ion batteries are the most common rechargeable batteries found in consumer electronics, such as laptops.
However, they take a long time to charge; researchers have assumed until now that there was a speed limit on the lithium ions and electrons that pass through the batteries to form an electrochemical circuit.
Gerbrand Ceder, at the Massachusetts Institute of Technology (MIT), US, and his colleagues used a computer simulation to model the movements of ions and electrons in a variant of the standard lithium material known as lithium iron phosphate.
The simulation indicated that ions were moving at great speed. “If transport of the lithium ions was so fast, something else had to be the problem,” Professor Ceder said. That problem turned out to be the way ions passed through the material. They pass through minuscule tunnels, whose entrances are present at the surface of the material.
However, the team discovered that to get into these channels, the ions had to be positioned directly in front of the tunnel entrances – if they were not, they could not get through.
The solution, Ceder discovered, was to engineer the material such that it has a so-called “beltway” that guides the ions towards the tunnel entrances.
A prototype battery made using the new technique could be charged in less than 20 seconds – in comparison to six minutes with an untreated sample of the material.
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