Tag Archives: supercapacitor

A solar, self-charging supercapacitor for wearable technology

Ravinder Dahiya, Carlos García Núñez, and their colleagues at the University of Glasgow (Scotland) strike again (see my May 10, 2017 posting for their first ‘solar-powered graphene skin’ research announcement). Last time it was all about robots and prosthetics, this time they’ve focused on wearable technology according to a July 18, 2018 news item on phys.org,

A new form of solar-powered supercapacitor could help make future wearable technologies lighter and more energy-efficient, scientists say.

In a paper published in the journal Nano Energy, researchers from the University of Glasgow’s Bendable Electronics and Sensing Technologies (BEST) group describe how they have developed a promising new type of graphene supercapacitor, which could be used in the next generation of wearable health sensors.

A July 18, 2018 University of Glasgow press release, which originated the news item, explains further,

Currently, wearable systems generally rely on relatively heavy, inflexible batteries, which can be uncomfortable for long-term users. The BEST team, led by Professor Ravinder Dahiya, have built on their previous success in developing flexible sensors by developing a supercapacitor which could power health sensors capable of conforming to wearer’s bodies, offering more comfort and a more consistent contact with skin to better collect health data.

Their new supercapacitor uses layers of flexible, three-dimensional porous foam formed from graphene and silver to produce a device capable of storing and releasing around three times more power than any similar flexible supercapacitor. The team demonstrated the durability of the supercapacitor, showing that it provided power consistently across 25,000 charging and discharging cycles.

They have also found a way to charge the system by integrating it with flexible solar powered skin already developed by the BEST group, effectively creating an entirely self-charging system, as well as a pH sensor which uses wearer’s sweat to monitor their health.

Professor Dahiya said: “We’re very pleased by the progress this new form of solar-powered supercapacitor represents. A flexible, wearable health monitoring system which only requires exposure to sunlight to charge has a lot of obvious commercial appeal, but the underlying technology has a great deal of additional potential.

“This research could take the wearable systems for health monitoring to remote parts of the world where solar power is often the most reliable source of energy, and it could also increase the efficiency of hybrid electric vehicles. We’re already looking at further integrating the technology into flexible synthetic skin which we’re developing for use in advanced prosthetics.” [emphasis mine]

In addition to the team’s work on robots, prosthetics, and graphene ‘skin’ mentioned in the May 10, 2017 posting the team is working on a synthetic ‘brainy’ skin for which they have just received £1.5m funding from the Engineering and Physical Science Research Council (EPSRC).

Brainy skin

A July 3, 2018 University of Glasgow press release discusses the proposed work in more detail,

A robotic hand covered in ‘brainy skin’ that mimics the human sense of touch is being developed by scientists.

University of Glasgow’s Professor Ravinder Dahiya has plans to develop ultra-flexible, synthetic Brainy Skin that ‘thinks for itself’.

The super-flexible, hypersensitive skin may one day be used to make more responsive prosthetics for amputees, or to build robots with a sense of touch.

Brainy Skin reacts like human skin, which has its own neurons that respond immediately to touch rather than having to relay the whole message to the brain.

This electronic ‘thinking skin’ is made from silicon based printed neural transistors and graphene – an ultra-thin form of carbon that is only an atom thick, but stronger than steel.

The new version is more powerful, less cumbersome and would work better than earlier prototypes, also developed by Professor Dahiya and his Bendable Electronics and Sensing Technologies (BEST) team at the University’s School of Engineering.

His futuristic research, called neuPRINTSKIN (Neuromorphic Printed Tactile Skin), has just received another £1.5m funding from the Engineering and Physical Science Research Council (EPSRC).

Professor Dahiya said: “Human skin is an incredibly complex system capable of detecting pressure, temperature and texture through an array of neural sensors that carry signals from the skin to the brain.

“Inspired by real skin, this project will harness the technological advances in electronic engineering to mimic some features of human skin, such as softness, bendability and now, also sense of touch. This skin will not just mimic the morphology of the skin but also its functionality.

“Brainy Skin is critical for the autonomy of robots and for a safe human-robot interaction to meet emerging societal needs such as helping the elderly.”

Synthetic ‘Brainy Skin’ with sense of touch gets £1.5m funding. Photo of Professor Ravinder Dahiya

This latest advance means tactile data is gathered over large areas by the synthetic skin’s computing system rather than sent to the brain for interpretation.

With additional EPSRC funding, which extends Professor Dahiya’s fellowship by another three years, he plans to introduce tactile skin with neuron-like processing. This breakthrough in the tactile sensing research will lead to the first neuromorphic tactile skin, or ‘brainy skin.’

To achieve this, Professor Dahiya will add a new neural layer to the e-skin that he has already developed using printing silicon nanowires.

Professor Dahiya added: “By adding a neural layer underneath the current tactile skin, neuPRINTSKIN will add significant new perspective to the e-skin research, and trigger transformations in several areas such as robotics, prosthetics, artificial intelligence, wearable systems, next-generation computing, and flexible and printed electronics.”

The Engineering and Physical Sciences Research Council (EPSRC) is part of UK Research and Innovation, a non-departmental public body funded by a grant-in-aid from the UK government.

EPSRC is the main funding body for engineering and physical sciences research in the UK. By investing in research and postgraduate training, the EPSRC is building the knowledge and skills base needed to address the scientific and technological challenges facing the nation.

Its portfolio covers a vast range of fields from healthcare technologies to structural engineering, manufacturing to mathematics, advanced materials to chemistry. The research funded by EPSRC has impact across all sectors. It provides a platform for future UK prosperity by contributing to a healthy, connected, resilient, productive nation.

It’s fascinating to note how these pieces of research fit together for wearable technology and health monitoring and creating more responsive robot ‘skin’ and, possibly, prosthetic devices that would allow someone to feel again.

The latest research paper

Getting back the solar-charging supercapacitors mentioned in the opening, here’s a link to and a citation for the team’s latest research paper,

Flexible self-charging supercapacitor based on graphene-Ag-3D graphene foam electrodes by Libu Manjakka, Carlos García Núñez, Wenting Dang, Ravinder Dahiya. Nano Energy Volume 51, September 2018, Pages 604-612 DOI: https://doi.org/10.1016/j.nanoen.2018.06.072

This paper is open access.

‘Lilliputian’ skyscraper: white graphene for hydrogen storage

This story comes from Rice University (Texas, US). From a March 12, 2018 news item on Nanowerk,

Rice University engineers have zeroed in on the optimal architecture for storing hydrogen in “white graphene” nanomaterials — a design like a Lilliputian skyscraper with “floors” of boron nitride sitting one atop another and held precisely 5.2 angstroms apart by boron nitride pillars.

Caption Thousands of hours of calculations on Rice University’s two fastest supercomputers found that the optimal architecture for packing hydrogen into “white graphene” involves making skyscraper-like frameworks of vertical columns and one-dimensional floors that are about 5.2 angstroms apart. In this illustration, hydrogen molecules (white) sit between sheet-like floors of graphene (gray) that are supported by boron-nitride pillars (pink and blue). Researchers found that identical structures made wholly of boron-nitride had unprecedented capacity for storing readily available hydrogen. Credit Lei Tao/Rice University

A March 12, 2018 Rice University news release (also on EurekAlert), which originated the news item, goes into extensive detail about the work,

“The motivation is to create an efficient material that can take up and hold a lot of hydrogen — both by volume and weight — and that can quickly and easily release that hydrogen when it’s needed,”  [emphasis mine] said the study’s lead author, Rouzbeh Shahsavari, assistant professor of civil and environmental engineering at Rice.

Hydrogen is the lightest and most abundant element in the universe, and its energy-to-mass ratio — the amount of available energy per pound of raw material, for example — far exceeds that of fossil fuels. It’s also the cleanest way to generate electricity: The only byproduct is water. A 2017 report by market analysts at BCC Research found that global demand for hydrogen storage materials and technologies will likely reach $5.4 billion annually by 2021.

Hydrogen’s primary drawbacks relate to portability, storage and safety. While large volumes can be stored under high pressure in underground salt domes and specially designed tanks, small-scale portable tanks — the equivalent of an automobile gas tank — have so far eluded engineers.

Following months of calculations on two of Rice’s fastest supercomputers, Shahsavari and Rice graduate student Shuo Zhao found the optimal architecture for storing hydrogen in boron nitride. One form of the material, hexagonal boron nitride (hBN), consists of atom-thick sheets of boron and nitrogen and is sometimes called white graphene because the atoms are spaced exactly like carbon atoms in flat sheets of graphene.

Previous work in Shahsavari’s Multiscale Materials Lab found that hybrid materials of graphene and boron nitride could hold enough hydrogen to meet the Department of Energy’s storage targets for light-duty fuel cell vehicles.

“The choice of material is important,” he said. “Boron nitride has been shown to be better in terms of hydrogen absorption than pure graphene, carbon nanotubes or hybrids of graphene and boron nitride.

“But the spacing and arrangement of hBN sheets and pillars is also critical,” he said. “So we decided to perform an exhaustive search of all the possible geometries of hBN to see which worked best. We also expanded the calculations to include various temperatures, pressures and dopants, trace elements that can be added to the boron nitride to enhance its hydrogen storage capacity.”

Zhao and Shahsavari set up numerous “ab initio” tests, computer simulations that used first principles of physics. Shahsavari said the approach was computationally intense but worth the extra effort because it offered the most precision.

“We conducted nearly 4,000 ab initio calculations to try and find that sweet spot where the material and geometry go hand in hand and really work together to optimize hydrogen storage,” he said.

Unlike materials that store hydrogen through chemical bonding, Shahsavari said boron nitride is a sorbent that holds hydrogen through physical bonds, which are weaker than chemical bonds. That’s an advantage when it comes to getting hydrogen out of storage because sorbent materials tend to discharge more easily than their chemical cousins, Shahsavari said.

He said the choice of boron nitride sheets or tubes and the corresponding spacing between them in the superstructure were the key to maximizing capacity.

“Without pillars, the sheets sit naturally one atop the other about 3 angstroms apart, and very few hydrogen atoms can penetrate that space,” he said. “When the distance grew to 6 angstroms or more, the capacity also fell off. At 5.2 angstroms, there is a cooperative attraction from both the ceiling and floor, and the hydrogen tends to clump in the middle. Conversely, models made of purely BN tubes — not sheets — had less storage capacity.”

Shahsavari said models showed that the pure hBN tube-sheet structures could hold 8 weight percent of hydrogen. (Weight percent is a measure of concentration, similar to parts per million.) Physical experiments are needed to verify that capacity, but that the DOE’s ultimate target is 7.5 weight percent, and Shahsavari’s models suggests even more hydrogen can be stored in his structure if trace amounts of lithium are added to the hBN.

Finally, Shahsavari said, irregularities in the flat, floor-like sheets of the structure could also prove useful for engineers.

“Wrinkles form naturally in the sheets of pillared boron nitride because of the nature of the junctions between the columns and floors,” he said. “In fact, this could also be advantageous because the wrinkles can provide toughness. If the material is placed under load or impact, that buckled shape can unbuckle easily without breaking. This could add to the material’s safety, which is a big concern in hydrogen storage devices.

“Furthermore, the high thermal conductivity and flexibility of BN may provide additional opportunities to control the adsorption and release kinetics on-demand,” Shahsavari said. “For example, it may be possible to control release kinetics by applying an external voltage, heat or an electric field.”

I may be wrong but this “The motivation is to create an efficient material that can take up and hold a lot of hydrogen — both by volume and weight — and that can quickly and easily release that hydrogen when it’s needed, …”  sounds like a supercapacitor. One other comment, this research appears to be ‘in silico’, i.e., all the testing has been done as computer simulations and the proposed materials themselves have yet to be tested.

Here’s a link to and a citation for the paper,

Merger of Energetic Affinity and Optimal Geometry Provides New Class of Boron Nitride Based Sorbents with Unprecedented Hydrogen Storage Capacity by Rouzbeh Shahsavari and Shuo Zhao. Small Vol. 14 Issue 10 DOI: 10.1002/smll.201702863 Version of Record online: 8 MAR 2018

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Do you want that coffee with some graphene on toast?

These scientists are excited:

For those who prefer text, here’s the Rice University Feb. 13, 2018 news release (received via email and available online here and on EurekAlert here) Note: Links have been removed),

Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.”

The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.

The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny RFID tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said. “All that could be placed not on a separate tag on the food, but on the food itself.”

Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”

The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.

Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.

“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”

The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.

Rice alumnus Ruquan Ye is co-lead author of the study. Co-authors are Rice graduate student Yilun Li and postdoctoral fellow Swatantra Pratap Singh and Professor Christopher Arnusch of Ben-Gurion University of the Negev, Israel. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research supported the research.

Here’s a link to and a citation for the paper,

Laser-Induced Graphene by Multiple Lasing: Toward Electronics on Cloth, Paper, and Food by Yieu Chyan, Ruquan Ye†, Yilun Li, Swatantra Pratap Singh, Christopher J. Arnusch, and James M. Tour. ACS Nano DOI: 10.1021/acsnano.7b08539 Publication Date (Web): February 13, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

h/t Feb. 13, 2018 news item on Nanowerk

Yarns that harvest and generate energy

The researchers involved in this work are confident enough about their prospects that they will be  patenting their research into yarns. From an August 25, 2017 news item on Nanowerk,

An international research team led by scientists at The University of Texas at Dallas and Hanyang University in South Korea has developed high-tech yarns that generate electricity when they are stretched or twisted.

In a study published in the Aug. 25 [2017] issue of the journal Science (“Harvesting electrical energy from carbon nanotube yarn twist”), researchers describe “twistron” yarns and their possible applications, such as harvesting energy from the motion of ocean waves or from temperature fluctuations. When sewn into a shirt, these yarns served as a self-powered breathing monitor.

“The easiest way to think of twistron harvesters is, you have a piece of yarn, you stretch it, and out comes electricity,” said Dr. Carter Haines, associate research professor in the Alan G. MacDiarmid NanoTech Institute at UT Dallas and co-lead author of the article. The article also includes researchers from South Korea, Virginia Tech, Wright-Patterson Air Force Base and China.

An August 25, 2017 University of Texas at Dallas news release, which originated the news item, expands on the theme,

Yarns Based on Nanotechnology

The yarns are constructed from carbon nanotubes, which are hollow cylinders of carbon 10,000 times smaller in diameter than a human hair. The researchers first twist-spun the nanotubes into high-strength, lightweight yarns. To make the yarns highly elastic, they introduced so much twist that the yarns coiled like an over-twisted rubber band.

In order to generate electricity, the yarns must be either submerged in or coated with an ionically conducting material, or electrolyte, which can be as simple as a mixture of ordinary table salt and water.

“Fundamentally, these yarns are supercapacitors,” said Dr. Na Li, a research scientist at the NanoTech Institute and co-lead author of the study. “In a normal capacitor, you use energy — like from a battery — to add charges to the capacitor. But in our case, when you insert the carbon nanotube yarn into an electrolyte bath, the yarns are charged by the electrolyte itself. No external battery, or voltage, is needed.”

When a harvester yarn is twisted or stretched, the volume of the carbon nanotube yarn decreases, bringing the electric charges on the yarn closer together and increasing their energy, Haines said. This increases the voltage associated with the charge stored in the yarn, enabling the harvesting of electricity.

Stretching the coiled twistron yarns 30 times a second generated 250 watts per kilogram of peak electrical power when normalized to the harvester’s weight, said Dr. Ray Baughman, director of the NanoTech Institute and a corresponding author of the study.

“Although numerous alternative harvesters have been investigated for many decades, no other reported harvester provides such high electrical power or energy output per cycle as ours for stretching rates between a few cycles per second and 600 cycles per second.”

Lab Tests Show Potential Applications

In the lab, the researchers showed that a twistron yarn weighing less than a housefly could power a small LED, which lit up each time the yarn was stretched.

To show that twistrons can harvest waste thermal energy from the environment, Li connected a twistron yarn to a polymer artificial muscle that contracts and expands when heated and cooled. The twistron harvester converted the mechanical energy generated by the polymer muscle to electrical energy.

“There is a lot of interest in using waste energy to power the Internet of Things, such as arrays of distributed sensors,” Li said. “Twistron technology might be exploited for such applications where changing batteries is impractical.”

The researchers also sewed twistron harvesters into a shirt. Normal breathing stretched the yarn and generated an electrical signal, demonstrating its potential as a self-powered respiration sensor.

“Electronic textiles are of major commercial interest, but how are you going to power them?” Baughman said. “Harvesting electrical energy from human motion is one strategy for eliminating the need for batteries. Our yarns produced over a hundred times higher electrical power per weight when stretched compared to other weavable fibers reported in the literature.”

Electricity from Ocean Waves

“In the lab we showed that our energy harvesters worked using a solution of table salt as the electrolyte,” said Baughman, who holds the Robert A. Welch Distinguished Chair in Chemistry in the School of Natural Sciences and Mathematics. “But we wanted to show that they would also work in ocean water, which is chemically more complex.”

In a proof-of-concept demonstration, co-lead author Dr. Shi Hyeong Kim, a postdoctoral researcher at the NanoTech Institute, waded into the frigid surf off the east coast of South Korea to deploy a coiled twistron in the sea. He attached a 10 centimeter-long yarn, weighing only 1 milligram (about the weight of a mosquito), between a balloon and a sinker that rested on the seabed.

Every time an ocean wave arrived, the balloon would rise, stretching the yarn up to 25 percent, thereby generating measured electricity.

Even though the investigators used very small amounts of twistron yarn in the current study, they have shown that harvester performance is scalable, both by increasing twistron diameter and by operating many yarns in parallel.

“If our twistron harvesters could be made less expensively, they might ultimately be able to harvest the enormous amount of energy available from ocean waves,” Baughman said. “However, at present these harvesters are most suitable for powering sensors and sensor communications. Based on demonstrated average power output, just 31 milligrams of carbon nanotube yarn harvester could provide the electrical energy needed to transmit a 2-kilobyte packet of data over a 100-meter radius every 10 seconds for the Internet of Things.”

Researchers from the UT Dallas Erik Jonsson School of Engineering and Computer Science and Lintec of America’s Nano-Science & Technology Center also participated in the study.

The investigators have filed a patent on the technology.

In the U.S., the research was funded by the Air Force, the Air Force Office of Scientific Research, NASA, the Office of Naval Research and the Robert A. Welch Foundation. In Korea, the research was supported by the Korea-U.S. Air Force Cooperation Program and the Creative Research Initiative Center for Self-powered Actuation of the National Research Foundation and the Ministry of Science.

Here’s a link to and a citation for the paper,

Harvesting electrical energy from carbon nanotube yarn twist by Shi Hyeong Kim, Carter S. Haines, Na Li, Keon Jung Kim, Tae Jin Mun, Changsoon Choi, Jiangtao Di, Young Jun Oh, Juan Pablo Oviedo, Julia Bykova, Shaoli Fang, Nan Jiang, Zunfeng Liu, Run Wang, Prashant Kumar, Rui Qiao, Shashank Priya, Kyeongjae Cho, Moon Kim, Matthew Steven Lucas, Lawrence F. Drummy, Benji Maruyama, Dong Youn Lee, Xavier Lepró, Enlai Gao, Dawood Albarq, Raquel Ovalle-Robles, Seon Jeong Kim, Ray H. Baughman. Science 25 Aug 2017: Vol. 357, Issue 6353, pp. 773-778 DOI: 10.1126/science.aam8771

This paper is behind a paywall.

Dexter Johnson in an Aug. 25, 2017 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) delves further into the research,

“Basically what’s happening is when we stretch the yarn, we’re getting a change in capacitance of the yarn. It’s that change that allows us to get energy out,” explains Carter Haines, associate research professor at UT Dallas and co-lead author of the paper describing the research, in an interview with IEEE Spectrum.

This makes it similar in many ways to other types of energy harvesters. For instance, in other research, it has been demonstrated—with sheets of rubber with coated electrodes on both sides—that you can increase the capacitance of a material when you stretch it and it becomes thinner. As a result, if you have charge on that capacitor, you can change the voltage associated with that charge.

“We’re more or less exploiting the same effect but what we’re doing differently is we’re using an electric chemical cell to do this,” says Haines. “So we’re not changing double layer capacitance in normal parallel plate capacitors. But we’re actually changing the electric chemical capacitance on the surface of a super capacitor yarn.”

While there are other capacitance-based energy harvesters, those other devices require extremely high voltages to work because they’re using parallel plate capacitors, according to Haines.

Dexter asks good questions and his post is very informative.

Making wearable technology more comfortable—with green tea for squishy supercapacitor

Researchers in India have designed a new type of wearable technology based on green team. From a Feb. 15, 2017 news item on plys.org,

Wearable electronics are here—the most prominent versions are sold in the form of watches or sports bands. But soon, more comfortable products could become available in softer materials made in part with an unexpected ingredient: green tea. Researchers report in ACS’ The Journal of Physical Chemistry C a new flexible and compact rechargeable energy storage device for wearable electronics that is infused with green tea polyphenols.

A Feb. 15, 2017 American Chemical Society (ACS) news release, (also on EurekAlert), which originated the news item, provides a little more information about the squishy supercapacitors (Note: Links have been removed),

Powering soft wearable electronics with a long-lasting source of energy remains a big challenge. Supercapacitors could potentially fill this role — they meet the power requirements, and can rapidly charge and discharge many times. But most supercapacitors are rigid, and the compressible supercapacitors developed so far have run into roadblocks. They have been made with carbon-coated polymer sponges, but the coating material tends to bunch up and compromise performance. Guruswamy Kumaraswamy, Kothandam Krishnamoorthy and colleagues wanted to take a different approach.

The researchers prepared polymer gels in green tea extract, which infuses the gel with polyphenols. The polyphenols converted a silver nitrate solution into a uniform coating of silver nanoparticles. Thin layers of conducting gold and poly(3,4-ethylenedioxythiophene) were then applied. And the resulting supercapacitor demonstrated power and energy densities of 2,715 watts per kilogram and 22 watt-hours per kilogram — enough to operate a heart rate monitor, LEDs or a Bluetooth module. The researchers tested the device’s durability and found that it performed well even after being compressed more than 100 times.

The authors acknowledge funding from the University Grants Commission of India, the Council of Scientific and Industrial Research (India) and the Board of Research in Nuclear Sciences (India).

Here’s a link to and a citation for the paper,

Elastic Compressible Energy Storage Devices from Ice Templated Polymer Gels treated with Polyphenols by Chayanika Das, Soumyajyoti Chatterjee, Guruswamy Kumaraswamy, and Kothandam Krishnamoorthy. J. Phys. Chem. C, Article ASAP DOI: 10.1021/acs.jpcc.6b12822 Publication Date (Web): January 26, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

Superconductivity with spin

Vivid lines of light tracing a pattern reminiscent of a spinning top toy Courtesy: Harvard University

Vivid lines of light tracing a pattern reminiscent of a spinning top toy Courtesy: Harvard University

An Oct. 14, 2016 Harvard University John A. Paulson School of Engineering and Applied Sciences (SEAS) press release (also on EurekAlert) by Leah Burrows describes how scientists have discovered a way to transmit spin information through supercapacitors,

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have made a discovery that could lay the foundation for quantum superconducting devices. Their breakthrough solves one the main challenges to quantum computing: how to transmit spin information through superconducting materials.

Every electronic device — from a supercomputer to a dishwasher — works by controlling the flow of charged electrons. But electrons can carry so much more information than just charge; electrons also spin, like a gyroscope on axis.

Harnessing electron spin is really exciting for quantum information processing because not only can an electron spin up or down — one or zero — but it can also spin any direction between the two poles. Because it follows the rules of quantum mechanics, an electron can occupy all of those positions at once. Imagine the power of a computer that could calculate all of those positions simultaneously.

A whole field of applied physics, called spintronics, focuses on how to harness and measure electron spin and build spin equivalents of electronic gates and circuits.

By using superconducting materials through which electrons can move without any loss of energy, physicists hope to build quantum devices that would require significantly less power.

But there’s a problem.

According to a fundamental property of superconductivity, superconductors can’t transmit spin. Any electron pairs that pass through a superconductor will have the combined spin of zero.

In work published recently in Nature Physics, the Harvard researchers found a way to transmit spin information through superconducting materials.

“We now have a way to control the spin of the transmitted electrons in simple superconducting devices,” said Amir Yacoby, Professor of Physics and of Applied Physics at SEAS and senior author of the paper.

It’s easy to think of superconductors as particle super highways but a better analogy would be a super carpool lane as only paired electrons can move through a superconductor without resistance.

These pairs are called Cooper Pairs and they interact in a very particular way. If the way they move in relation to each other (physicists call this momentum) is symmetric, then the pair’s spin has to be asymmetric — for example, one negative and one positive for a combined spin of zero. When they travel through a conventional superconductor, Cooper Pairs’ momentum has to be zero and their orbit perfectly symmetrical.

But if you can change the momentum to asymmetric — leaning toward one direction — then the spin can be symmetric. To do that, you need the help of some exotic (aka weird) physics.

Superconducting materials can imbue non-superconducting materials with their conductive powers simply by being in close proximity. Using this principle, the researchers built a superconducting sandwich, with superconductors on the outside and mercury telluride in the middle. The atoms in mercury telluride are so heavy and the electrons move so quickly, that the rules of relativity start to apply.

“Because the atoms are so heavy, you have electrons that occupy high-speed orbits,” said Hechen Ren, coauthor of the study and graduate student at SEAS. “When an electron is moving this fast, its electric field turns into a magnetic field which then couples with the spin of the electron. This magnetic field acts on the spin and gives one spin a higher energy than another.”

So, when the Cooper Pairs hit this material, their spin begins to rotate.

“The Cooper Pairs jump into the mercury telluride and they see this strong spin orbit effect and start to couple differently,” said Ren. “The homogenous breed of zero momentum and zero combined spin is still there but now there is also a breed of pairs that gains momentum, breaking the symmetry of the orbit. The most important part of that is that the spin is now free to be something other than zero.”

The team could measure the spin at various points as the electron waves moved through the material. By using an external magnet, the researchers could tune the total spin of the pairs.

“This discovery opens up new possibilities for storing quantum information. Using the underlying physics behind this discovery provides also new possibilities for exploring the underlying nature of superconductivity in novel quantum materials,” said Yacoby.

Here’s a link to and a citation for the paper,

Controlled finite momentum pairing and spatially varying order parameter in proximitized HgTe quantum wells by Sean Hart, Hechen Ren, Michael Kosowsky, Gilad Ben-Shach, Philipp Leubner, Christoph Brüne, Hartmut Buhmann, Laurens W. Molenkamp, Bertrand I. Halperin, & Amir Yacoby. Nature Physics (2016) doi:10.1038/nphys3877 Published online 19 September 2016

This paper is behind a paywall.

Exploring the science of Iron Man (prior to the opening of Captain America: Civil War, aka, Captain America vs. Iron Man)

Not unexpectedly, there’s a news item about science and Iron Man (it’s getting quite common for the science in movies to be promoted and discussed) just a few weeks before the movie Captain America: Civil War or, as it’s also known, Captain America vs. Iron Man opens in the US. From an April 26, 2016 news item on phys.org,

… how much of our favourite superheros’ power lies in science and how much is complete fiction?

As Iron Man’s name suggests, he wears a suit of “iron” which gives him his abilities—superhuman strength, flight and an arsenal of weapons—and protects him from harm.

In scientific parlance, the Iron man suit is an exoskeleton which is worn outside the body to enhance it.

An April 26, 2016 posting by Chris Marr on the ScienceNetwork Western Australia blog, which originated the news item, provides an interesting overview of exoskeletons and some of the scientific obstacles still to be overcome before they become commonplace,

In the 1960s, the first real powered exoskeleton appeared—a machine integrated with the human frame and movements which provided the wearer with 25 times his natural lifting capacity.

The major drawback then was that the unit itself weighed in at 680kg.

UWA [University of Western Australia] Professor Adrian Keating suggests that some of the technology seen in the latest Marvel blockbuster, such as controlling the exoskeleton with simple thoughts, will be available in the near future by leveraging ongoing advances of multi-disciplinary research teams.

“Dust grain-sized micromachines could be programmed to cooperate to form reconfigurable materials such as the retractable face mask, for example,” Prof Keating says.

However, all of these devices are in need of a power unit small enough to be carried yet providing enough capacity for more than a few minutes of superhuman use, he says.

Does anyone have a spare Arc Reactor?

Currently, most exoskeleton development has been for medical applications, with devices designed to give mobility to amputees and paraplegics, and there are a number in commercial production and use.

Dr Lei Cui, who lectures in Mechatronics at Curtin University, has recently developed both a hand and leg exoskeleton, designed for use by patients who have undergone surgery or have nerve dysfunction, spinal injuries or muscular dysfunction.

“Currently we use an internal battery that lasts about two hours in the glove, which can be programmed for only four different movement patterns,” Dr Cui says.

Dr Cui’s exoskeletons are made from plastic, making them light but offering little protection compared to the titanium exterior of Stark’s favourite suit.

It’s clear that we are a long way from being able to produce a working Iron Man suit at all, let alone one that flies, protects the wearer and has the capacity to fight back.

This is not the first time I’ve featured a science and pop culture story here. You can check out my April 28, 2014 posting for a story about how Captain America’s shield could be a supercapacitor (it also has a link to a North Carolina State University blog featuring science and other comic book heroes) and there is my May 6, 2013 post about Iron Man 3 and a real life injectable nano-network.

As for ScienceNetwork Western Australia, here’s more from their About SWNA page,

ScienceNetwork Western Australia (SNWA) is an online science news service devoted to sharing WA’s achievements in science and technology.

SNWA is produced by Scitech, the state’s science and technology centre and supported by the WA Government’s Office of Science via the Department of the Premier and Cabinet.

Our team of freelance writers work with in-house editors based at Scitech to bring you news from all fields of science, and from the research, government and private industry sectors working throughout the state. Our writers also produce profile stories on scientists. We collaborate with leading WA institutions to bring you Perspectives from prominent WA scientists and opinion leaders.

We also share news of science-related events and information about the greater WA science community including WA’s Chief Scientist, the Premier’s Science Awards, Innovator of the Year Awards and information on regional community science engagement.

Since our commencement in 2003 we have grown to share WA’s stories with local, national and global audiences. Our articles are regularly republished in print and online media in the metropolitan and regional areas.

Bravo to the Western Australia government! I wish there  initiatives of this type in Canada, the closest we have is the French language Agence Science-Presse supported by the Province of Québec.

A new ink for energy storage devices from the Hong Kong Polytechnic University

Energy storage is not the first thought that leaps to mind when ink is mentioned. Live and learn, eh? A Sept. 23, 2015 news item on Nanowerk describes the connection (Note: A link has been removed),

 The Department of Applied Physics of The Hong Kong Polytechnic University (PolyU) has developed a simple approach to synthesize novel environmentally friendly manganese dioxide ink by using glucose (“Aqueous Manganese Dioxide Ink for Paper-Based Capacitive Energy Storage Devices”).

The MnO2 ink could be used for the production of light, thin, flexible and high performance energy storage devices via ordinary printing or even home-used printers. The capacity of the MnO2 ink supercapacitor is more than 30 times higher than that of a commercial capacitor of the same weight of active material (e.g. carbon powder), demonstrating the great potential of MnO2 ink in significantly enhancing the performances of energy storage devices, whereas its production cost amounts to less than HK$1.

A Sept. 23, 2015 PolyU media release, which originated the news item, expands on the theme,

MnO2 is a kind of environmentally-friendly material and it is degradable. Given the environmental compatibility and high potential capacity of MnO2, it has always been regarded as an ideal candidate for the electrode materials of energy storage devices. The conventional MnO2 electrode preparation methods suffer from high cost, complicated processes and could result in agglomeration of the MnO2 ink during the coating process, leading to the reduction of electrical conductivity. The PolyU research team has developed a simple approach to synthesize aqueous MnO2 ink. Firstly, highly crystalline carbon particles were prepared by microwave hydrothermal method, followed by a morphology transmission mechanism at room temperature. The MnO2 ink can be coated on various substrates, such as conductive paper, plastic and glass. Its thickness and weight can also be controlled for the production of light, thin, transparent and flexible energy storage devices. Substrates coated by MnO2 ink can easily be erased if required, facilitating the fabrication of electronic devices.

PolyU researchers coated the MnO2 ink on conductive A4 paper and fabricated a capacitive energy storage device with maximum energy density and power density amounting to 4 mWh•cm-3 and 13 W•cm-3 respectively. The capacity of the MnO2 ink capacitor is more than 30 times higher than that of a commercial capacitor of the same weight of active material (e.g. carbon powder), demonstrating the great potential of MnO2 ink in significantly enhancing the performances of energy storage devices. Given the small size, light, thin, flexible and high energy capacity properties of the MnO2 ink energy storage device, it shows a potential in wide applications. For instance, in wearable devices and radio-frequency identification systems, the MnO2 ink supercapacitor could be used as the power sources for the flexible and “bendable” display panels, smart textile, smart checkout tags, sensors, luggage tracking tags, etc., thereby contributing to the further development of these two areas.

The related paper has been recently published on Angewandte Chemie International Edition, a leading journal in Chemistry. The research team will work to further improve the performance of the MnO2 ink energy storage device in the coming two years, with special focus on increasing the voltage, optimizing the structure and synthesis process of the device. In addition, further tests will be conducted to integrate the MnO2 ink energy storage device with other energy collection systems.

Here’s a link to and a citation for the paper,

Aqueous Manganese Dioxide Ink for Paper-Based Capacitive Energy Storage Devices by Jiasheng Qian, Huanyu Jin, Dr. Bolei Chen, Mei Lin, Dr. Wei Lu, Dr. Wing Man Tang, Dr. Wei Xiong, Prof. Lai Wa Helen Chan, Prof. Shu Ping Lau, and Dr. Jikang Yuan. Angewandte Chemie International Edition Volume 54, Issue 23, pages 6800–6803, June 1, 2015 DOI: 10.1002/anie.201501261 Article first published online: 17 APR 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Lomiko Metals, Graphene ESD, and supercapacitors

My hats off to Lomiko Metals for its publicity efforts. The company cranks out at least three news releases per month and that’s a lot of work for a small company. The Feb. 23, 2015 news release (also a Feb. 24, 2015 news item on Azonano) announces a newish research relationship and a new position for Lomiko Metal’s Chief Esecutive Officer (CEO), A. Paul Gill,

Lomiko Metals Inc. is pleased to announce Graphene Energy Storage Devices Corp. has signed a research agreement with the Research Foundation of Stony Brook University (SBU). Graphene ESD Corp. will partner with the SBU Center for Advanced Sensor Technologies (Sensor CAT) to develop new supercapacitors designs for energy storage. Lomiko Metals Inc. currently owns a 40% stake in Graphene ESD and Mr. A. Paul Gill, CEO of Lomiko, is now appointed a Director of Graphene ESD.

“This agreement is a significant step in expanding collaboration between industry and academia in the furtherance of our Center’s mission to create high-tech jobs in New York,” stated Peter Shkolnikov, Deputy Director of the Sensor CAT. “Energy storage is a rapidly growing field, with SBU is on the forefront of electrochemical energy storage research”.
Initially, Graphene ESD Corp. will provide $50,000 in cash funding to the SUNY Research Foundation which will host research at its Sensor CAT facilities on SBU campus in Stony Brook, NY.

I last mentioned Graphene ESD (Graphene Energy Storage Devices) in a Dec. 5, 2014 posting  when Lomiko announced it was investing in the venture.

As for Lomiko’s publicity efforts, there’s this intriguing Feb. 1, 2015 news release (Note: Links have been removed),

European Union 5 Billion Euro Graphene Research Fund Goliath Moves to Commercialization Efforts While Lomiko Efforts Start to Bear Fruit

Lomiko (“Lomiko”) (TSX-V:LMR, OTC:LMRMF, FSE:DH8B) is raising the alarm regarding Canada’s lacklustre efforts to capitalize on new manufacturing and nanotechnology opportunities while concentrating on the oil industry.

“In twenty years the effect of graphene and 3D printing on society will be amazing, very much like the impact of plastics in the sixties and computers in the eighties. I hope that Canadian finance and government institutions recognize the opportunity for Canada to establish a competitive advantage,” stated A. Paul Gill, CEO. “The EU has put 5 Billion euros into graphene research while most Canadians don’t even know about this Nobel-prize winning material.”

Mr. Gill was recently interview by Business Television regarding Lomiko’s efforts in the field. View the 90 second video clip by clicking here.

Lomiko has been working for two years on graphene commercialization efforts. Partnered with Graphene Labs, Lomiko has launched two ventures in the graphene field. On January 5, 2015 Lomiko announced a summary of its activity in 2014 and 2015 plans to spin-off two new technology companies after the successful launch of Graphene 3D Lab, a company foc used on developing 3D Printing hardware and materials. Lomiko continues to hold 4,396,916 shares or 10.43% of Graphene 3D Lab, 40% of newly formed Graphene Energy Storage Devices (Graphene ESD) and 100% of Lomiko Technologies Inc.

While mention of the European Union’s Graphene Flagship (funding of 1B Euros over 10 years) in contrast with the Canadian scene’s lack of major initiatives in this area seems unexceptionable, it’s a bit unusual to make so much fuss of a funding entity with which you have no relationship (from the Feb. 1, 2015 news release; Note: Links have been removed),

EU FUND – Graphene Flagship

The Graphene Flagship’s overriding goal is to take graphene, related layered materials and hybrid systems from a state of raw potential to a point where they can revolutionize multiple industries. This may bring a new dimension to future technology and put Europe at the heart of the process, with a manifold return on the investment as technological innovation, economic exploitation and societal benefits.

This requires the focus of the Flagship to evolve over the years, placing more resources in areas where this transition is more likely. To accomplish this the Graphene Flagship is looking for new industrial partners that bring in specific industrial and technology transfer competences or capabilities that complement the present consortium. Regarding what nations are eligible to apply, the European Commission (EC) rules are found here.

The selected new partners will be incorporated in the scientific and technological work packages of the core project under the Horizon 2020 phase of the Flagship that is presently being planned and that will run during 1 April 2016 – 31 March 2018.

While Gill’s point is well taken, lately there seems to be more action than usual on the Canadian graphene scene.

Investment in graphene (Grafoid), the Canadian government, and a 2015 federal election (Feb. 23, 2015)

NanoXplore: graphene and graphite in Québec (Canada) (Feb. 20, 2015)

For anyone who’d like to peruse Lomiko Metals’ news releases, go here.

Canadian nano: Lomiko Metals and its graphene supercapacitor project and NanoTech Security at a TEDx in Vancouver (Canada)

As best I can determine Lomiko Metals is involved in a graphene-based supercapacitor project with at least two interlocking pieces. Piece one is described in an Oct. 28, 2014 news item on Azonano,

Lomiko Metals Inc. and its 100% owned subsidiary Lomiko Technologies Inc. are pleased to announce an agreement to license from Megahertz Power Systems Ltd. rights to manufacture and sell three (3) power converter system designs, acquire a pending supply contract with a Canadian LED system integrator and support the research and development of new products.

“The Power Converter Market is a multi-billion dollar market. With the increasing demand for energy-efficient electronic devices, the advent of re-chargeable batteries and the new market for quick-charge supercapacitors, Lomiko has the opportunity to move into a growing market with a profitable business model.”, stated A. Paul Gill, CEO. [emphasis mine]

Lomiko will establish cash-flow under the current Customer Contract within six months which is based on proven and in-demand devices designed by MegaHertz. The creation of an e-commerce site in three to four (3-4) months will increase the customer base for the Licensed Power Systems over the estimated five (5) year product cycle. In the long term, Lomiko and MegaHertz will work on innovative new designs that power products using graphite and graphene based devices to dramatically raise operating efficiencies and help reduce the energy waste for the Electronic equipment, Energy Storage and Automotive Industries worldwide. [emphasis mine]

You can read more about the details in the Azonano news item or in the Lomiko Metals Oct. 27, 2014 news release.

As for piece two, Lomiko Metals has announced a supecapacitor project which would seem to align with the objectives mentioned in the October 2014 MegaHertz deal “… Lomiko and MegaHertz will work on innovative new designs that power products using graphite and graphene based devices to dramatically raise operating efficiencies and help reduce the energy waste … .” From a Dec. 4, 2014 news item on Azonano,

Lomiko Metals Inc. is very pleased to announce it has signed an agreement to invest in a new graphene-related venture, Graphene Energy Storage Devices (Graphene ESD Corp.), a U.S. Corporation.

On December 4, 2013, Lomiko reported on a successful conclusion to Phase I of its Graphene Supercapacitor Project which involved Graphene Laboratories Inc. and Stony Brook University. Graphene ESD Corp. has been formed to commercialize the technology and bring the graphene-based energy storage devices to market.

Supercapacitors bridge the gap between conventional capacitors and rechargeable batteries. They store the most energy per unit volume or mass (energy density) among capacitors. Supercapacitors power density is generally 10 to 100 times greater than normal capacitors or batteries. This results in much shorter charge/discharge cycles than batteries. Additionally, they will tolerate many more charge and discharge cycles than batteries. Incorporation of graphene material in supercapacitor electrodes may further improve energy and power density of the device. Graphene ESD Corp. will develop low-cost graphene-based supercapacitor devices that will be capable of even higher discharge currents. The development will focus on large-scale devices that are projected to have the lowest cost of power and stored energy in its class.

“As reported December 4, 2013, the Phase I Graphene Supercapacitor project yielded encouraging results. Graphene ESD Corp. will build on the success of this project and will be developing a graphene-based supercapacitor. [emphasis mine] The device is designed as a versatile energy storage solution for electronics, electric vehicles and electric grid.” stated A. Paul Gill, CEO of Lomiko Metals Inc. [emphasis mine] Graphene is finding new application in sensors, electronics, and advanced materials. Energy storage is a rapidly developing field which can benefit from the outstanding properties of graphene. We believe that graphene-based devices will deliver the best value for multiple energy storage applications.”

You can find more details both in the Azonano news item and in the Lomiko Metals Dec. 3, 2014 news release.

The second half of this post’s headline concerns a talk by Clint Landrock, Executive Vice President of Products for NanoTech Security Corp. and more, at the Renfrew-Collingwood (a neighbourhood in Vancouver, Canada) TEDx. From an Oct. 29, 2014 news item on Azonano,

Nanotech Security Corp. today announced that Vice President Clint Landrock presented at TEDxRenfrewCollingwood. The independently organized TED event was held on October 24, 2014.

The day-long event brought together more than 400 creators, catalysis, designers and thinkers from the Vancouver area to share ideas around the theme “Rock, Paper, Scissors.” Landrock presented on the influence of nature on innovation in technology, using Nanotech’s story as one example of what can be achieved when companies turn to nature as a source of inspiration. …

Landrock’s talk (a little over 11 mins. running time) has now been posted on YouTube or you can find it here. The organizers have posted this description of Landrock,

Clint serves as the Executive Vice President of Products for NanoTech Security Corp., and is a co-founder of IDME Technologies Corp.  He is an expert in the study of nano-optics and biomimicry. Clint currently holds several patents and over a dozen peer-reviewed publications in the field. He completed his bachelor degree in aerospace engineering at Ryerson Polytechnic University in Toronto, and his Masters of Applied Sciences at Simon Fraser University. Clint’s interests include commercial applications of nanotechnology and smart polymers, biomimicry, alpine and rock climbing and generally being outside.

I haven’t watched the talk in its entirety but he starts with the wonder and the dark side of technology. As his company, NanoTech Security, is a spin-off from Simon Fraser University and the technology is based on the nanostructures found on the Blue Morpho butterfly’s wing, I imagine the rest of his talk consists of biomimcry and ways of imitating nature as a means of dealing with the damaging aspects resulting from some of our current technologies.