Dust-sized supercapacitor packs the same voltage as a AAA battery

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An array of 90 tubular biosupercapacitors
Research Group Prof. Dr. Oliver G. Schmidt
An array of 90 tubular biosupercapacitors
Research Group Prof. Dr. Oliver G. Schmidt
Prof. Dr. Oliver G. Schmidt has led the development of a novel, tiny supercapacitor that is biocompatible
Jacob Müller

By combining miniaturized electronics with some origami-inspired fabrication, scientists in Germany have developed what they say is the smallest microsupercapacitor in existence. Smaller than a speck of a dust but with a similar voltage to a AAA battery, the groundbreaking energy storage device is not only safe for use in the human body, but actually makes use of key ingredients in the blood to supercharge its performance.

The scientists behind the new device were working within the realm of nano-supercapacitors (nBSC), which are conventional capacitors but scaled down to the sub-millimeter scale. Developing these types of devices is tricky enough, but the researchers sought to make one that could work safely in the human body to power tiny sensors and implants, which requires swapping out problematic materials and corrosive electrolytes for ones that are biocompatible.

These devices are known as biosupercapacitors and the smallest ones developed to date is larger than 3 mm3, but the scientists have made a huge leap forward in terms of how tiny biosupercapacitors can be. The construction starts with a stack of polymeric layers that are sandwiched together with a light-sensitive photo-resist material that acts as the current collector, a separator membrane, and electrodes made from an electrically conductive biocompatible polymer called PEDOT:PSS.

This stack is placed on a wafer-thin surface that is subjected to high mechanical tension, which causes the various layers to detach in a highly controlled fashion and fold up origami-style into a nano-biosupercapacitor with a volume 0.001 mm3, occupying less space than a grain of dust. These tubular biosupercapacitors are therefore 3,000 times smaller than those developed previously, but with a voltage roughly the same as an AAA battery (albeit with far lower actual current flow).

These tiny devices were then placed in saline, blood plasma and blood, where they demonstrated an ability to successfully store energy. The biosupercapacitor proved particularly effective in blood, where it retained up to 70 percent of its capacity after 16 hours of operation. Another reason blood may be a suitable home for the team's biosupercapacitor is that the device works with inherent redox enzymatic reactions and living cells in the solution to supercharge its own charge storage reactions, boosting its performance by 40 percent.

Prof. Dr. Oliver G. Schmidt has led the development of a novel, tiny supercapacitor that is biocompatible
Jacob Müller

The team also subjected the device to the forces it might experience in blood vessels where flow and pressure fluctuate, by placing them in microfluidic channels, kind of like wind-tunnel testing for aerodynamics, where it stood up well. They also used three of the devices chained together to successfully power a tiny pH sensor, which could be placed in the blood vessels to measure pH and detect abnormalities that could be indicative of disease, such as a tumor growth.

"It is extremely encouraging to see how new, extremely flexible, and adaptive microelectronics is making it into the miniaturized world of biological systems," says research group leader Prof. Dr. Oliver G. Schmidt.

The research was published in the journal Nature Communications

Source: Chemnitz University of Technology

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Gareth Smith
An extremely useless article, the voltage is totally immaterial and not in any way surprising for a capacitor of any size. But what is the capacity, like milliamps hours, the whole dust sized and AA battery in the title is total clickbait and erodes the credibility of the website. A totally useless 2 minutes of my life as no useful information was gained.
voltage of a capacitor is maybe not the most important metric but its still important.
given we are talking about tiny dut sized capacitor, powering super low power electronics/sensors, but it still needs a certain voltage to operate any semi conductor. not requiring voltage conversion is a huge point in this case.
also milliamps hours is not more meaning if you dont know the voltage. energy density is probably the biggest bottleneck in this kind of application
Well, Gareth covered most of what I was going to post but...
A capacitor will have whatever voltage it was charged to right up until the breakdown voltage is reached. There is no defined voltage for an AAA cell -- I have them in the house now in 1.2V and 1.5V and 3.7V varieties.
Wonderful research - if only for proof of concept. Nothing like a solution looking for a problem to solve!
What Gareth said.
The highly-misleading title is disappointing.
i think the important thing here is the apparently new method of photolithography used to fabricate it, using photoresist as a charge plate. Although yeah, not specifying the capacity does make it sound kinda fishy
Very good news for the world
Syed Kaleem
My understanding is as follows.
1.WEIGHT MATTERS. Capacitors are notorious for size, they do not deliver same energy as normal car batteries. This will change that thinking . In other words they will deliver and may actually better it. Essentially a 1000 AH battery weighs about 50 Lbs , these may weigh may be 1/2 lbs. BIG DIFFERENCE
2.ENERGY. These deliver same amount of energy 1000 AH if not more.
3.SIZE MATTERS. Normal Capacitors to deliver 1000 AH may require a space of 10feet x 10 feet x 1 foot. with these you may get away with 1ft x 1ft x1ft or less.