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10/3/11

Nanoscoops for battery anode

Charging a cell phone or laptop could take minutes instead of hours, due to the development of a new nanomaterial for battery electrode. The material is made up of what is called nanoscoops containing "cones" of carbon and aluminum with "scoops" of silicon on top. These nanoscoops would replace the graphite anode used in today's lithium-ion batteries, which are the most common type of batteries found in consumer electronics.
Lithium-ion batteries
Lithium-ion batteries are used in cell phone, laptop or other devices. The problem with today's lithium-ion batteries is that they must be charged and discharged slowly to prevent the anode of battery from falling apart when done at a fast rate. This is because inside the battery, lithium ions move in and out of the anode, causing the negatively charged electrode to change in its volume putting stress on the anode and, over time, this stress accumulates to the point where the anode stops working. If the charge and discharge is done very slowly then the stress buildup is not that serious a problem, but if it is done too quickly then the stress builds to an extent that the battery gets damaged.
Anode from nanomaterials
To address this problem, the Researchers of Rensselaer Polytechnic Institute (RPI) in New York have developed a new anode made from nano materials and have made a button cell Li-ion battery with a nanoscoop anode which can charge 40 to 60 times faster than a typical Li-ion battery which would be useful in electric cars to accelerate after stopping.
Since nanomaterials have very flexible structures they have been tried in the past. They show some improvement but do not have the quick charge-discharge time exhibited by the nanoscoops.
Instead of just one nanomaterial, the researchers created a layered structure of carbon nanorods coated with a thin layer of aluminum and topped with a scoop of silicon. Each layer acts as a sort of "stress absorber" for the next layer, reducing the overall stress felt by each individual material and resulting in an improved anode. Because a gradient in strain is developed the structure can not peel off or break off the substrate.
The amount of charge stored in a Li-ion battery is directly related to the mass of the electrode. And because these nanoscoops are so light, necessary mass can be obtained either by growing longer nanoscoops to possibly increase the length from its current 170 nanometers to a few microns or by creating more layers of nanoscoops.

1 Responses to “Nanoscoops for battery anode”

tianode said...
January 25, 2012 at 4:01 AM

I like engineering, but I love the creative input.

Electrochemical Equipments


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