Nano-Onions Give Supercapacitors Extra Oomph

Nested carbon cages endow supercapacitors with super charging and discharging rates

3 min read

17 August 2010—As we enter an era of ”smart” environments—buildings that know their structural weaknesses, military vests that detect toxic chemicals, rivers that monitor their own flood levels—engineers have turned their attention to a new class of energy-storage devices to power the sensors that will make our world smarter. Ultracapacitors, also called supercapacitors or electrochemical double-layer capacitors, can last for many more charge and discharge cycles and deliver energy faster than a chemical battery, although they store less energy.

Trying to make supercapacitors a bit more super, researchers in the United States and France have devised a snowflake-size device whose electrodes are coated with nanoscale carbon spheres. Thanks to its microscale electrodes and the unique onionlike layering of the carbon spheres, the device charges and discharges more quickly than a commercial ultracapacitor, the researchers report in the journal Nature Nanotechnology. Such a device might be ideal for powering wireless sensors that must transmit quick, powerful signals.

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Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.


If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

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