University of Illinois researchers have developed a technology that will allow dramatically faster charging and discharging of batteries without sacrificing energy storage capacity.
The research may be significant for the future of electric vehicles, whose limited battery capacity and resulting frequent recharging needs are seen as an obstacle to market growth.
The researchers developed a three-dimensional nanostructure for battery cathodes that facilitates the faster charging.
"This system that we have gives you capacitor-like power with battery-like energy," said Paul Braun, a professor of materials science and engineering. "Most capacitors store very little energy. They can release it very fast, but they can't hold much. Most batteries store a reasonably large amount of energy, but they can't provide or receive energy rapidly. This does both."
The performance of typical lithium-ion (Li-ion) or nickel metal hydride (NiMH) rechargeable batteries degrades significantly when they are rapidly charged or discharged.
One solution for this is to make the active material in the battery a thin film, which allows for very fast charging and discharging. But such a structure reduces the capacity to nearly zero because the active material lacks volume to store energy.
Braun's group wrapped a thin film into a three-dimensional structure, achieving both high active volume (high capacity) and large current.
As a result, charging and recharging can happen 10 to 100 times faster than with traditional technology. Phones could be recharged in seconds and laptops in minutes.
According to a University of Illinois press release, Braun is particularly optimistic for the batteries' potential in electric vehicles.
"If you had the ability to charge rapidly, instead of taking hours to charge the vehicle you could potentially have vehicles that would charge in similar times as needed to refuel a car with gasoline," Braun said in the press statement.
"If you had five-minute charge capability, you would think of this the same way you do an internal combustion engine. You would just pull up to a charging station and fill up."
All of the processes the group used are also suitable for larger scale manufacturing.
Moreover, the group demonstrated its new technology with both NiMH and Li-ion batteries, but a wide range of battery materials could be used.
"It's very universal, so if someone comes up with a better battery chemistry, this concept applies," said Braun. "This is not linked to one very specific kind of battery, but rather it's a new paradigm in thinking about a battery in three dimensions for enhancing properties."
A detailed report on the new technology can be read in the journal "Nature nanotechnology."
IMAGE: Illinois researchers developed a 3-D nanostructure for battery cathodes that allows for very rapid charge and discharge, without sacrificing capacity.
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