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A Battery that Lasts 10 Times Longer and Charges 10 Times Faster

The Lithium-Ion Battery of the Future

Written by Brian Hicks
Posted November 17, 2011

A phone battery that charges 10 times faster and holds its charge 10 times longer is in the works...

Futurity reports that researchers have combined two chemical engineering approaches to fix the problem most people have with their cell phones, iPads, etc.: devices need to charge quicker and need to be plugged in less.

Advanced Energy Material journal says this new technology will be available in devices for consumers to purchase in the next three to five years.

“We have found a way to extend a new lithium-ion battery’s charge life by 10 times,” says Harold H. Kung, professor of chemical and biological engineering at Northwestern University, reports Futurity. “Even after 150 charges, which would be one year or more of operation, the battery is still five times more effective than lithium-ion batteries on the market today.”

How do lithium-ion batteries work? Futurity describes the science behind these types of batteries:

Lithium-ion batteries charge through a chemical reaction in which lithium ions are sent between two ends of the battery, the anode and the cathode. As energy in the battery is used, the lithium ions travel from the anode, through the electrolyte, and to the cathode; as the battery is recharged, they travel in the reverse direction.

The technology in current lithium-ion batteries is limited in holding its charge because of the amount it can fit into the anode or cathode. The other limitation is the time it take to charge, which is determined by the speed the lithium ions travel from the electrolyte into the anode.

What makes current batteries lose their charge? Futurity says:

In current rechargeable batteries, the anode that is made of layer upon layer of carbon-based graphene sheets, can only accommodate one lithium atom for every six carbon atoms. To increase energy capacity, scientists have previously experimented with replacing the carbon with silicon, as silicon can accommodate much more lithium: four lithium atoms for every silicon atom.

The speed of the lithium-ion batteries consumers use currently is limited, Futurity says,  because of:

…the extreme thinness of the graphene sheets: just one carbon atom thick, but by comparison, very long. During the charging process, a lithium ion must travel all the way to the outer edges of the graphene sheet before entering and coming to rest between the sheets. And because it takes so long for lithium to travel to the middle of the graphene sheet, a sort of ionic traffic jam occurs around the edges of the material.

Kung, along with other colleagues, are going to stabilize the silicon to maintain maximum charge capacity and plan to increase the charging speed by placing “…clusters of silicon between the graphene sheets, allowing for a greater number of lithium atoms in the electrode while utilizing the flexibility of graphene sheets to accommodate the volume changes of silicon during use.”

Kung and his team are also working with a chemical oxidation process to create a shortcut for the lithium ions to reach the anode.

In a few short years your devices will last the whole day, maybe even days, without having to be charged, eliminating the need to drag along a wall or car charger. You will no longer have to be stuck half way through your day with a dead phone.

That's all for now,

Cori

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