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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Emily Cooper

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.

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