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Graphene Ultracapacitor Could Shrink Systems

A more capacitor-like ultracapacitor could replace much bigger components

3 min read

23 September 2010—The ultracapacitor—the battery’s quicker cousin—just got faster and may one day help make portable electronics a lot smaller and lighter, according to a group of researchers. John Miller, president of the electrochemical capacitor company JME, in Shaker Heights, Ohio, and his team reported the new ultracapacitor design this week in Science.

Ultracapacitors don’t store quite as much charge as batteries but can charge and discharge in seconds rather than the minutes batteries take. This combination of speed and energy supply makes them attractive for things like regenerative braking, where the ultracapacitors would have only seconds to recharge as a car comes to a stop. But sometimes a second is still too long: Using nanometer-scale fins of graphene, the researchers built an ultracapacitor that can charge in less than a millisecond. This agility, its designers say, means that the devices could replace the ubiquitous bulky capacitors that smooth out the ripples in power supplies to free up precious space in gadgets and computers.

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan
LightGreen

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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