Category Archives: energy

Smartphone battery inspired by your guts?

The conversion of bacteria from an enemy to be vanquished at all costs to a ‘frenemy’, a friendly enemy supplying possible solutions for problems is fascinating. An Oct. 26, 2016 news item on Nanowerk falls into the ‘frenemy’ camp,

A new prototype of a lithium-sulphur battery – which could have five times the energy density of a typical lithium-ion battery – overcomes one of the key hurdles preventing their commercial development by mimicking the structure of the cells which allow us to absorb nutrients.

Researchers have developed a prototype of a next-generation lithium-sulphur battery which takes its inspiration in part from the cells lining the human intestine. The batteries, if commercially developed, would have five times the energy density of the lithium-ion batteries used in smartphones and other electronics.

An Oct. 26, 2016 University of Cambridge press release (also on EurekAlert), which originated the news item, expands on the theme and provides some good explanations of how lithium-ion batteries and lithium-sulphur batteries work (Note: A link has been removed),

The new design, by researchers from the University of Cambridge, overcomes one of the key technical problems hindering the commercial development of lithium-sulphur batteries, by preventing the degradation of the battery caused by the loss of material within it. The results are reported in the journal Advanced Functional Materials.

Working with collaborators at the Beijing Institute of Technology, the Cambridge researchers based in Dr Vasant Kumar’s team in the Department of Materials Science and Metallurgy developed and tested a lightweight nanostructured material which resembles villi, the finger-like protrusions which line the small intestine. In the human body, villi are used to absorb the products of digestion and increase the surface area over which this process can take place.

In the new lithium-sulphur battery, a layer of material with a villi-like structure, made from tiny zinc oxide wires, is placed on the surface of one of the battery’s electrodes. This can trap fragments of the active material when they break off, keeping them electrochemically accessible and allowing the material to be reused.

“It’s a tiny thing, this layer, but it’s important,” said study co-author Dr Paul Coxon from Cambridge’s Department of Materials Science and Metallurgy. “This gets us a long way through the bottleneck which is preventing the development of better batteries.”

A typical lithium-ion battery is made of three separate components: an anode (negative electrode), a cathode (positive electrode) and an electrolyte in the middle. The most common materials for the anode and cathode are graphite and lithium cobalt oxide respectively, which both have layered structures. Positively-charged lithium ions move back and forth from the cathode, through the electrolyte and into the anode.

The crystal structure of the electrode materials determines how much energy can be squeezed into the battery. For example, due to the atomic structure of carbon, each carbon atom can take on six lithium ions, limiting the maximum capacity of the battery.

Sulphur and lithium react differently, via a multi-electron transfer mechanism meaning that elemental sulphur can offer a much higher theoretical capacity, resulting in a lithium-sulphur battery with much higher energy density. However, when the battery discharges, the lithium and sulphur interact and the ring-like sulphur molecules transform into chain-like structures, known as a poly-sulphides. As the battery undergoes several charge-discharge cycles, bits of the poly-sulphide can go into the electrolyte, so that over time the battery gradually loses active material.

The Cambridge researchers have created a functional layer which lies on top of the cathode and fixes the active material to a conductive framework so the active material can be reused. The layer is made up of tiny, one-dimensional zinc oxide nanowires grown on a scaffold. The concept was trialled using commercially-available nickel foam for support. After successful results, the foam was replaced by a lightweight carbon fibre mat to reduce the battery’s overall weight.

“Changing from stiff nickel foam to flexible carbon fibre mat makes the layer mimic the way small intestine works even further,” said study co-author Dr Yingjun Liu.

This functional layer, like the intestinal villi it resembles, has a very high surface area. The material has a very strong chemical bond with the poly-sulphides, allowing the active material to be used for longer, greatly increasing the lifespan of the battery.

“This is the first time a chemically functional layer with a well-organised nano-architecture has been proposed to trap and reuse the dissolved active materials during battery charging and discharging,” said the study’s lead author Teng Zhao, a PhD student from the Department of Materials Science & Metallurgy. “By taking our inspiration from the natural world, we were able to come up with a solution that we hope will accelerate the development of next-generation batteries.”

For the time being, the device is a proof of principle, so commercially-available lithium-sulphur batteries are still some years away. Additionally, while the number of times the battery can be charged and discharged has been improved, it is still not able to go through as many charge cycles as a lithium-ion battery. However, since a lithium-sulphur battery does not need to be charged as often as a lithium-ion battery, it may be the case that the increase in energy density cancels out the lower total number of charge-discharge cycles.

“This is a way of getting around one of those awkward little problems that affects all of us,” said Coxon. “We’re all tied in to our electronic devices – ultimately, we’re just trying to make those devices work better, hopefully making our lives a little bit nicer.”

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

Advanced Lithium–Sulfur Batteries Enabled by a Bio-Inspired Polysulfide Adsorptive Brush by Teng Zhao, Yusheng Ye, Xiaoyu Peng, Giorgio Divitini, Hyun-Kyung Kim, Cheng-Yen Lao, Paul R. Coxon, Kai Xi, Yingjun Liu, Caterina Ducati, Renjie Chen, R. Vasant Kumar. Advanced Functional Materials DOI: 10.1002/adfm.201604069 First published: 26 October 2016

This paper is behind a paywall.

Caption: This is a computer visualization of villi-like battery material. Credit: Teng Zhao

Caption: This is a computer visualization of villi-like battery material. Credit: Teng Zhao

Boron nitride-graphene hybrid nanostructures could lead to next generation ‘green’ cars

An Oct. 24, 2016 phys.org news item describes research which may lead to improved fuel storage in ‘green’ cars,

Layers of graphene separated by nanotube pillars of boron nitride may be a suitable material to store hydrogen fuel in cars, according to Rice University scientists.

The Department of Energy has set benchmarks for storage materials that would make hydrogen a practical fuel for light-duty vehicles. The Rice lab of materials scientist Rouzbeh Shahsavari determined in a new computational study that pillared boron nitride and graphene could be a candidate.

An Oct. 24, 2016 Rice University news release (also on EurekAlert), which originated the news item, provides more detail (Note: Links have been removed),

Shahsavari’s lab had already determined through computer models how tough and resilient pillared graphene structures would be, and later worked boron nitride nanotubes into the mix to model a unique three-dimensional architecture. (Samples of boron nitride nanotubes seamlessly bonded to graphene have been made.)

Just as pillars in a building make space between floors for people, pillars in boron nitride graphene make space for hydrogen atoms. The challenge is to make them enter and stay in sufficient numbers and exit upon demand.

In their latest molecular dynamics simulations, the researchers found that either pillared graphene or pillared boron nitride graphene would offer abundant surface area (about 2,547 square meters per gram) with good recyclable properties under ambient conditions. Their models showed adding oxygen or lithium to the materials would make them even better at binding hydrogen.

They focused the simulations on four variants: pillared structures of boron nitride or pillared boron nitride graphene doped with either oxygen or lithium. At room temperature and in ambient pressure, oxygen-doped boron nitride graphene proved the best, holding 11.6 percent of its weight in hydrogen (its gravimetric capacity) and about 60 grams per liter (its volumetric capacity); it easily beat competing technologies like porous boron nitride, metal oxide frameworks and carbon nanotubes.

At a chilly -321 degrees Fahrenheit, the material held 14.77 percent of its weight in hydrogen.

The Department of Energy’s current target for economic storage media is the ability to store more than 5.5 percent of its weight and 40 grams per liter in hydrogen under moderate conditions. The ultimate targets are 7.5 weight percent and 70 grams per liter.

Shahsavari said hydrogen atoms adsorbed to the undoped pillared boron nitride graphene, thanks to  weak van der Waals forces. When the material was doped with oxygen, the atoms bonded strongly with the hybrid and created a better surface for incoming hydrogen, which Shahsavari said would likely be delivered under pressure and would exit when pressure is released.

“Adding oxygen to the substrate gives us good bonding because of the nature of the charges and their interactions,” he said. “Oxygen and hydrogen are known to have good chemical affinity.”

He said the polarized nature of the boron nitride where it bonds with the graphene and the electron mobility of the graphene itself make the material highly tunable for applications.

“What we’re looking for is the sweet spot,” Shahsavari said, describing the ideal conditions as a balance between the material’s surface area and weight, as well as the operating temperatures and pressures. “This is only practical through computational modeling, because we can test a lot of variations very quickly. It would take experimentalists months to do what takes us only days.”

He said the structures should be robust enough to easily surpass the Department of Energy requirement that a hydrogen fuel tank be able to withstand 1,500 charge-discharge cycles.

Shayeganfar [Farzaneh Shayeganfar], a former visiting scholar at Rice, is an instructor at Shahid Rajaee Teacher Training University in Tehran, Iran.

 

Caption: Simulations by Rice University scientists show that pillared graphene boron nitride may be a suitable storage medium for hydrogen-powered vehicles. Above, the pink (boron) and blue (nitrogen) pillars serve as spacers for carbon graphene sheets (gray). The researchers showed the material worked best when doped with oxygen atoms (red), which enhanced its ability to adsorb and desorb hydrogen (white). Credit: Lei Tao/Rice University

Caption: Simulations by Rice University scientists show that pillared graphene boron nitride may be a suitable storage medium for hydrogen-powered vehicles. Above, the pink (boron) and blue (nitrogen) pillars serve as spacers for carbon graphene sheets (gray). The researchers showed the material worked best when doped with oxygen atoms (red), which enhanced its ability to adsorb and desorb hydrogen (white). Credit: Lei Tao/Rice University

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

Oxygen and Lithium Doped Hybrid Boron-Nitride/Carbon Networks for Hydrogen Storage by Farzaneh Shayeganfar and Rouzbeh Shahsavari. Langmuir,  DOI: 10.1021/acs.langmuir.6b02997 Publication Date (Web): October 23, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

I last featured research by Shayeganfar and  Shahsavari on graphene and boron nitride in a Jan. 14, 2016 posting.

The volatile lithium-ion battery

On the heels of Samsung’s Galaxy Note 7 recall due to fires (see Alex Fitzpatrick’s Sept. 9, 2016 article for Time magazine for a good description of lithium-ion batteries and why they catch fire; see my May 29, 2013 posting on lithium-ion batteries, fires [including the airplane fires], and nanotechnology risk assessments), there’s new research on lithium-ion batteries and fires from China. From an Oct. 21, 2016 news item on Nanotechnology Now,

Dozens of dangerous gases are produced by the batteries found in billions of consumer devices, like smartphones and tablets, according to a new study. The research, published in Nano Energy, identified more than 100 toxic gases released by lithium batteries, including carbon monoxide.

An Oct. 20, 2016 Elsevier Publishing press release (also on EurekAlert), which originated the news item, expands on the theme,

The gases are potentially fatal, they can cause strong irritations to the skin, eyes and nasal passages, and harm the wider environment. The researchers behind the study, from the Institute of NBC Defence and Tsinghua University in China, say many people may be unaware of the dangers of overheating, damaging or using a disreputable charger for their rechargeable devices.

In the new study, the researchers investigated a type of rechargeable battery, known as a “lithium-ion” battery, which is placed in two billion consumer devices every year.

“Nowadays, lithium-ion batteries are being actively promoted by many governments all over the world as a viable energy solution to power everything from electric vehicles to mobile devices. The lithium-ion battery is used by millions of families, so it is imperative that the general public understand the risks behind this energy source,” explained Dr. Jie Sun, lead author and professor at the Institute of NBC Defence.

The dangers of exploding batteries have led manufacturers to recall millions of devices: Dell recalled four million laptops in 2006 and millions of Samsung Galaxy Note 7 devices were recalled this month after reports of battery fires. But the threats posed by toxic gas emissions and the source of these emissions are not well understood.

Dr. Sun and her colleagues identified several factors that can cause an increase in the concentration of the toxic gases emitted. A fully charged battery will release more toxic gases than a battery with 50 percent charge, for example. The chemicals contained in the batteries and their capacity to release charge also affected the concentrations and types of toxic gases released.

Identifying the gases produced and the reasons for their emission gives manufacturers a better understanding of how to reduce toxic emissions and protect the wider public, as lithium-ion batteries are used in a wide range of environments.

“Such dangerous substances, in particular carbon monoxide, have the potential to cause serious harm within a short period of time if they leak inside a small, sealed environment, such as the interior of a car or an airplane compartment,” Dr. Sun said.

Almost 20,000 lithium-ion batteries were heated to the point of combustion in the study, causing most devices to explode and all to emit a range of toxic gases. Batteries can be exposed to such temperature extremes in the real world, for example, if the battery overheats or is damaged in some way.

The researchers now plan to develop this detection technique to improve the safety of lithium-ion batteries so they can be used to power the electric vehicles of the future safely.

“We hope this research will allow the lithium-ion battery industry and electric vehicle sector to continue to expand and develop with a greater understanding of the potential hazards and ways to combat these issues,” Sun concluded.

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

Toxicity, a serious concern of thermal runaway from commercial Li-ion battery by Jie Sun, Jigang Li, Tian Zhou, Kai Yang, Shouping Wei, Na Tang, Nannan Dang, Hong Li, Xinping Qiu, Liquan Chend. Nano Energy Volume 27, September 2016, Pages 313–319  http://dx.doi.org/10.1016/j.nanoen.2016.06.031

This paper appears to be open access.

Nano-spike catalysts offer one step conversion of carbon dioxide to ethanol

An Oct. 12, 2016 news item on ScienceDaily makes an exciting announcement, if carbon-dixoide-conversion-to-fuel is one of your pet topics,

In a new twist to waste-to-fuel technology, scientists at the Department of Energy’s Oak Ridge National Laboratory [ORNL] have developed an electrochemical process that uses tiny spikes of carbon and copper to turn carbon dioxide, a greenhouse gas, into ethanol. Their finding, which involves nanofabrication and catalysis science, was serendipitous.

An Oct. 12, 2016 ORNL news release, which originated the news item, explains in greater detail,

“We discovered somewhat by accident that this material worked,” said ORNL’s Adam Rondinone, lead author of the team’s study published in ChemistrySelect. “We were trying to study the first step of a proposed reaction when we realized that the catalyst was doing the entire reaction on its own.”

The team used a catalyst made of carbon, copper and nitrogen and applied voltage to trigger a complicated chemical reaction that essentially reverses the combustion process. With the help of the nanotechnology-based catalyst which contains multiple reaction sites, the solution of carbon dioxide dissolved in water turned into ethanol with a yield of 63 percent. Typically, this type of electrochemical reaction results in a mix of several different products in small amounts.

“We’re taking carbon dioxide, a waste product of combustion, and we’re pushing that combustion reaction backwards with very high selectivity to a useful fuel,” Rondinone said. “Ethanol was a surprise — it’s extremely difficult to go straight from carbon dioxide to ethanol with a single catalyst.”

The catalyst’s novelty lies in its nanoscale structure, consisting of copper nanoparticles embedded in carbon spikes. This nano-texturing approach avoids the use of expensive or rare metals such as platinum that limit the economic viability of many catalysts.

“By using common materials, but arranging them with nanotechnology, we figured out how to limit the side reactions and end up with the one thing that we want,” Rondinone said.

The researchers’ initial analysis suggests that the spiky textured surface of the catalysts provides ample reactive sites to facilitate the carbon dioxide-to-ethanol conversion.

“They are like 50-nanometer lightning rods that concentrate electrochemical reactivity at the tip of the spike,” Rondinone said.

Given the technique’s reliance on low-cost materials and an ability to operate at room temperature in water, the researchers believe the approach could be scaled up for industrially relevant applications. For instance, the process could be used to store excess electricity generated from variable power sources such as wind and solar.

“A process like this would allow you to consume extra electricity when it’s available to make and store as ethanol,” Rondinone said. “This could help to balance a grid supplied by intermittent renewable sources.”

The researchers plan to refine their approach to improve the overall production rate and further study the catalyst’s properties and behavior.

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

High-Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle/N-Doped Graphene Electrode by Yang Song, Rui Peng, Dale Hensley, Peter Bonnesen, Liangbo Liang, Zili Wu, Harry Meyer III, Miaofang Chi, Cheng Ma, Bobby Sumpter and Adam Rondinone. Chemistry Select DOI: 10.1002/slct.201601169 First published: 28 September 2016

This paper is open access.

Cicada wings for anti-reflective surfaces

This bioinspired piece of research comes courtesy of China. From an Oct. 11, 2016 news item on Nanowerk,

A team of Shanghai Jiao Tong University researchers has used the shape of cicada wings as a template to create antireflective structures fabricated with one of the most intriguing semiconductor materials, titanium dioxide (TiO2). The antireflective structures they produced are capable of suppressing visible light — 450 to 750 nanometers — at different angles of incidence.

An Oct. 11,2016 American Institute of Physics news release, which originated the news item, explains why the researchers focused on cicada wings and how their observations led to a new anti-reflective material,

Why cicada wings? The surfaces of the insect’s wings are composed of highly ordered, tiny vertical “nano-nipple” arrays, according to the researchers. As they report this week in Applied Physics Letters, from AIP Publishing, the resulting biomorphic TiO2 surface they created with antireflective structures shows a significant decrease in reflectivity.

“This can be attributed to an optimally graded refractive index profile between air and the TiO2 via antireflective structures on the surface,” explained Wang Zhang, associate professor at State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University in China.

Small spaces between the ordered nano-antireflective structures “can be thought of as a light-transfer path that let incident light rays into the interior surface of the biomorphic TiO2 — allowing the incident light rays to completely enter the structure,” Zhang continued. “The multiple reflective and scattering effects of the antireflective structures prevented the incident light from returning to the outside atmosphere.”

Significantly, the team’s work relies on “a simple and low-cost sol-gel (wet chemical) method to fabricate biomorphic TiO2 with precise subwavelength antireflective surfaces,” Zhang pointed out. “The TiO2 was a purely anatase phase (a mineral form of TiO2), which has unique antireflective surfaces. This led to an optimally graded refractive index and, ultimately, to angle-dependent antireflective properties within the visible light range.”

In terms of applications, the team’s biomorphic TiO2 antireflective structures “show great potential for photovoltaic devices such as solar cells,” Zhang said. “We expect our work to inspire and motivate engineers to develop antireflective surfaces with unique structures for various practical applications.”

Even after high calcination at 500 C, the antireflective structures retain their morphology and high-performance antireflection properties. These qualities should enable the coatings to withstand harsh environments and make them suitable for long-term applications.

In the future, the team plans “to reduce the optical losses in solar cells by using materials with a higher refractive index such as tantalum pentoxide or any other semiconductor materials,” Zhang said.

I. Photograph and scanning electron microscope characterizations of a black cicada wing (Cryptympana atrata Fabricius). II. Synthesis process of biomorphic TiO2 with ordered nano-nipple array structures. III. Counter map angle-dependent antireflection of biomorphic TiO2 and non-templated TiO2, respectively. CREDIT: Shanghai Jiao Tong University

I. Photograph and scanning electron microscope characterizations of a black cicada wing (Cryptympana atrata Fabricius).
II. Synthesis process of biomorphic TiO2 with ordered nano-nipple array structures.
III. Counter map angle-dependent antireflection of biomorphic TiO2 and non-templated TiO2, respectively.
CREDIT: Shanghai Jiao Tong University

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

Angle dependent antireflection property of TiO2 inspired by cicada wings by Imran Zada, Wang Zhang, Yao Li, Peng Sun, Nianjin Cai, Jiajun Gu, Qinglei Liu, Huilan Su, and Di Zhang.  Appl. Phys. Lett. 109, 153701 (2016); http://dx.doi.org/10.1063/1.4962903

This paper appears to be open access.

Scaling up quantum dot, solar-powered windows

An Oct. 12, 2016 news item on phys.org announces that Los Alamos National Laboratory (US) may have taken a step towards scaling up quantum dot, solar-powered windows for industrial production (Note: A link has been removed),

In a paper this week for the journal Nature Energy, a Los Alamos National Laboratory research team demonstrates an important step in taking quantum dot, solar-powered windows from the laboratory to the construction site by proving that the technology can be scaled up from palm-sized demonstration models to windows large enough to put in and power a building.

“We are developing solar concentrators that will harvest sunlight from building windows and turn it into electricity, using quantum-dot based luminescent solar concentrators,” said lead scientist Victor Klimov. Klimov leads the Los Alamos Center for Advanced Solar Photophysics (CASP).

Los Alamos Center for Advanced Solar Photophysics researchers hold a large prototype solar window. From left to right: Jaehoon Lim, Kaifeng Wu, Victor Klimov, Hongbo Li.

Los Alamos Center for Advanced Solar Photophysics researchers hold a large prototype solar window. From left to right: Jaehoon Lim, Kaifeng Wu, Victor Klimov, Hongbo Li.

An Oct. 11, 2016 Los Alamos National Laboratory news release, which originated the news item, describes the work in more detail,

Luminescent solar concentrators (LSCs) are light-management devices that can serve as large-area sunlight collectors for photovoltaic cells. An LSC consists of a slab of transparent glass or plastic impregnated or coated with highly emissive fluorophores. After absorbing solar light shining onto a larger-area face of the slab, LSC fluorophores re-emit photons at a lower energy and these photons are guided by total internal reflection to the device edges where they are collected by photovoltaic cells.

At Los Alamos, researchers expand the options for energy production while minimizing the impact on the environment, supporting the Laboratory mission to strengthen energy security for the nation.

In the Nature Energy paper, the team reports on large LSC windows created using the “doctor-blade” technique for depositing thin layers of a dot/polymer composite on top of commercial large-area glass slabs. The “doctor-blade” technique comes from the world of printing and uses a blade to wipe excess liquid material such as ink from a surface, leaving a thin, highly uniform film behind. “The quantum dots used in LSC devices have been specially designed for the optimal performance as LSC fluorophores and to exhibit good compatibility with the polymer material that holds them on the surface of the window,” Klimov noted.

LSCs use colloidal quantum dots to collect light because they have properties such as widely tunable absorption and emission spectra, nearly 100 percent emission efficiencies, and high photostability (they don’t break down in sunlight).

If the cost of an LSC is much lower than that of a photovoltaic cell of comparable surface area and the LSC efficiency is sufficiently high, then it is possible to considerably reduce the cost of producing solar electricity, Klimov said. “Semitransparent LSCs can also enable new types of devices such as solar or photovoltaic windows that could turn presently passive building facades into power generation units.”

The quantum dots used in this study are semiconductor spheres with a core of one material and a shell of another. Their absorption and emission spectra can be tuned almost independently by varying the size and/or composition of the core and the shell. This allows the emission spectrum to be tuned by the parameters of the dot’s core to below the onset of strong optical absorption, which is itself tuned by the parameters of the dot’s shell. As a result, loss of light due to self-absorption is greatly reduced. “This tunability is the key property of these specially designed quantum dots that allows for record-size, high-performance LSC devices,” Klimov said.

The “LSC quantum dots” were synthesized by Jaehoon Lim (a postdoctoral research associate). Hongbo Li (postdoctoral research associate), and Kaifeng Wu (postdoctoral Director’s Fellow) developed the procedures for encapsulating quantum dots into polymer matrices and their deposition onto glass slabs by doctor-blading. Hyung-Jun Song (postdoctoral research associate) fabricated prototypes of complete LSC-solar-cell devices and characterized them.

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

Doctor-blade deposition of quantum dots onto standard window glass for low-loss large-area luminescent solar concentrators by Hongbo Li, Kaifeng Wu, Jaehoon Lim, Hyung-Jun Song, & Victor I. Klimov. Nature Energy 1, Article number: 16157 (2016) doi:10.1038/nenergy.2016.157 Published online: 10 October 2016

This paper is behind a paywall.

Switching of a single-atom channel

An Oct. 28, 2016 news item on phys.org announces a single-atom switch,

Robert Wolkow is no stranger to mastering the ultra-small and the ultra-fast. A pioneer in atomic-scale science with a Guinness World Record to boot (for a needle with a single atom at the point), Wolkow’s team, together with collaborators at the Max Plank Institute in Hamburg, have just released findings that detail how to create atomic switches for electricity, many times smaller than what is currently used.

What does it all mean? With applications for practical systems like silicon semi-conductor electronics, it means smaller, more efficient, more energy-conserving computers, as just one example of the technology revolution that is unfolding right before our very eyes (if you can squint that hard).

“This is the first time anyone’s seen a switching of a single-atom channel,” explains Wolkow, a physics professor at the University of Alberta and the Principal Research Officer at Canada’s National Institute for Nanotechnology. “You’ve heard of a transistor—a switch for electricity—well, our switches are almost a hundred times smaller than the smallest on the market today.”

An Oct. 28, 2016 University of Alberta news release by Jennifer Pascoe, which originated the news item, describes the research in more detail,

Today’s tiniest transistors operate at the 14 nanometer level, which still represents thousands of atoms. Wolkow’s and his team at the University of Alberta, NINT, and his spinoff QSi, have worked the technology down to just a few atoms. Since computers are simply a composition of many on/off switches, the findings point the way not only to ultra-efficient general purpose computing but also to a new path to quantum computing.

Green technology for the digital economy

“We’re using this technology to make ultra-green, energy-conserving general purpose computers but also to further the development of quantum computers. We are building the most energy conserving electronics ever, consuming about a thousand times less power than today’s electronics.”

While the new tech is small, the potential societal, economic, and environmental impact of Wolkow’s discovery is very large. Today, our electronics consume several percent of the world’s electricity.  As the size of the energy footprint of the digital economy increases, material and energy conservation is becoming increasingly important.

Wolkow says there are surprising benefits to being smaller, both for normal computers, and, for quantum computers too. “Quantum systems are characterized by their delicate hold on information. They’re ever so easily perturbed. Interestingly though, the smaller the system gets, the fewer upsets.” Therefore, Wolkow explains, you can create a system that is simultaneously amazingly small, using less material and churning through less energy, while holding onto information just right.

Smaller systems equal smaller environmental footprint

When the new technology is fully developed, it will lead to not only a smaller energy footprint but also more affordable systems for consumers. “It’s kind of amazing when everything comes together,” says Wolkow.

Wolkow is one of the few people in the world talking about atom-scale manufacturing and believes we are witnessing the beginning of the revolution to come. He and his team have been working with large-scale industry leader Lockheed Martin as the entry point to the market.

“It’s something you don’t even hear about yet, but atom-scale manufacturing is going to be world-changing. People think it’s not quite doable but, but we’re already making things out of atoms routinely. We aren’t doing it just because. We are doing it because the things we can make have ever more desirable properties. They’re not just smaller. They’re different and better. This is just the beginning of what will be at least a century of developments in atom-scale manufacturing, and it will be transformational.”

Bill Mah in a Nov. 1, 2016 article for the Edmonton Journal delves a little further into issues around making transistors smaller and the implications of a single-atom switch,

Current computers use transistors, which are essentially valves for flowing streams of electrons around a circuit. In recent years, engineers have found ways to make these devices smaller, but pushing electrons through narrow spaces raises the danger of the machines overheating and failing.

“The transistors get too hot so you have to run them slower and more gently, so we’re getting more power in modern computers because there are more transistors, but we can’t run them very quickly because they make a lot of heat and they actually just shut down and fail.”

The smallest transistors are currently about 14 nanometres. A nanometre is one-billionth of a metre and contains groupings of 1,000 or more atoms. The switches detailed by Wolkow and his colleagues will shrink them down to just a few atoms.

Potential benefits from the advance could lead to much more energy-efficient and smaller computers, an increasingly important consideration as the power consumption of digital devices keeps growing.

“The world is using about three per cent of our energy today on digital communications and computers,” Wolkow said. “Various reports I’ve seen say that it could easily go up to 10 or 15 per cent in a couple of decades, so it’s crucial that we get that under control.”

Wolkow’s team has received funding from companies such as Lockheed Martin and local investors.

The advances could also open a path to quantum computing. “It turns out these same building blocks … enable a quantum computer, so we’re kind of feverishly working on that at the same time.”

There is an animation illustrating a single-atom switch,

This animation represents an electrical current being switched on and off. Remarkably, the current is confined to a channel that is just one atom wide. Also, the switch is made of just one atom. When the atom in the centre feels an electric field tugging at it, it loses its electron. Once that electron is lost, the many electrons in the body of the silicon (to the left) have a clear passage to flow through. When the electric field is removed, an electron gets trapped in the central atom, switching the current off.  Courtesy: University of Alberta

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

Time-resolved single dopant charge dynamics in silicon by Mohammad Rashidi, Jacob A. J. Burgess, Marco Taucer, Roshan Achal, Jason L. Pitters, Sebastian Loth, & Robert A. Wolkow. Nature Communications 7, Article number: 13258 (2016)  doi:10.1038/ncomms13258 Published online: 26 October 2016

This paper is open access.

Panasonic powers up a village in Myanmar with photovoltaics

This story reminded me of an account I read (when I was working in the city’s archives) of Vancouver’s (Canada) West End where residents were advised against going out at night after the sun set because there was no street lighting. And, in those days (19th century) the city was still somewhat forested with bears, foxes, coyotes, and other wild animals being a lot more common that they are today. (Vancouver is a big city but there are coyote warning signs on its beaches and residents of North Vancouver [a nearby municipality] occasionally have awakened to find bears in their backyards.)

Moving onto the true subject of this posting, Myanmar and power, a Sept. 22, 2016 news item on phys.org announced the presence of a new power grid in a village in Myanmar,

Panasonic Corporation provided the Power Supply Station; a stand-alone photovoltaic power package, to the village of Yin Ma Chaung, a Magway Region of the Republic of the Union of Myanmar. The Power Supply Station is installed as part of a CSR [Corporate social responsibility?] effort by the Sustainable Alternative Livelihood Development Project, supported by the Mae Fah Luang Foundation under Royal Patronage (MFL Foundation) of the Kingdom of Thailand. This project was rolled out in partnership with Mitsui & Co., Ltd as one of their CSR activities, and funded by donations to support the mission of the MFL Foundation’s activities.

A Sept. 22, 2016 Panasonic press release, which originated the news item, provides more detail about the power station,

Panasonic’s power supply station consists of solar modules and storage batteries, which enables energy to be created, stored and managed efficiently. The whole system is able to supply electricity to the entire village, relieving approximately 140 households in the non-electrified mountainous village by powering up electrical appliances and lights, which are essential and important in daily lives.

The presence of lightings [sic] in the village makes it possible for villagers to move around during the night, as prior to that; they were unable to do so since the area is inhabited by poisonous snakes. In addition, all the street lights have time-switch LED bulbs that could also make use of limited electricity, efficiently.

In Myanmar, its off-grid areas are said to be at the highest level among the ASEAN [Association of Southeast Asian Nations] countries, at approximately 68%1 across the nation. In its countryside, the number reaches to an estimate of 84%2 households being unconnected to electricity. To step up on its efforts, Panasonic also installed a refrigerator in the village’s meeting area to store anti-venom drugs. With a well-powered point, the meeting area has thus serves as a center for welfare, entertainment and other purposes.

The whole initiative aimed to provide additional electricity to surrounding villages as well; contributing to the entire Yenan Chuang Township.

Panasonic will continue to develop localized solutions in its bid to provide electricity to off-grid regions and improves the standard of living amongst communities, around the world.

The Power Supply Station is equipped with twelve Panasonic HIT solar modules and can output approximately 3 kW of electricity. It is also equipped with 24 storage batteries (approximately 17 kWh), enabling it to supply stored power.

Features of the Power Supply Station stand-alone photovoltaic power package

(1) Stable quality and performance achieved by production at the factory

The Power Supply Station was developed as a mass produced product to deliver stable quality overseas. The unit for this project was manufactured and its quality was controlled by our Thai subsidiary, Panasonic Eco Solutions Steel (Thailand) Co., Ltd., before delivery to Myanmar.

(2)Simple and quick assembly for portability and expansion

The station is designed to eliminate the need for on-site professional construction work, allowing an electrical contractor to easily and quickly install it.

(3) Utilization of proven Panasonic technologies

The station uses Panasonic HIT 3 solar modules to provide power efficiently, even in restricted spaces. The company’s newly developed power supply main unit acts as the energy management system to monitor the remaining electricity level of the lead-acid storage batteries and controls supply and demand, reducing deterioration of the batteries. This reduces the life-cycle cost and maintenance man-hours for the storage batteries.

There is a video which reminds you of what life could be like without electricity in the context of this Power Supply Station installation,

It’s nice to be reminded of how magical electricity and all its accoutrements are as so many of us with easy access take it all for granted.

A better buckypaper

‘Buckyballs’ is a slang term for buckminster fullerenes, spheres made up of a carbon atoms arranged in hexagons. It’s a tribute of sorts to Buckminster Fuller, an architect, designer, systems theorist and more, who developed a structure known as a geodesic dome which bears a remarkable resemblance to the carbon atom spheres known as buckyballs or buckminster fullerenes or fullerenes or C60 (for a carbon-based fullerene) for short. Carbon nanotubes are sometimes called buckytubes and there is a material known as buckypaper. A Sept. 20, 2016 news item on Nanowerk describes the latest work on buckypaper,

Researchers at the Masdar Institute of Science and Technology have developed a novel type of “buckypaper” – a thin film composed of carbon nanotubes – that has better thermal and electrical properties than most types of buckypaper previously developed. Researchers believe the innovative buckypaper could be used to create ultra-lightweight composite materials for numerous aerospace and energy applications, including advanced lightning strike protection on airplanes and more powerful lithium-ion batteries.

Masdar Institute’s Associate Professors of Mechanical and Materials Engineering Dr. Rashid Abu Al-Rub and Dr. Amal Al Ghaferi, along with Post-Doctoral Researcher Dr. Hammad Younes, developed the buckypaper with carbon nanostructures provided by global security, aerospace, and information technology company Lockheed Martin.

A Sept. 20, 2016 Masdar Institute (United Arab Emirates) press release, which originated the news item, describes the research in more detail,

The black, powdery flakes provided by Lockheed Martin’s Applied NanoStructured Solutions (ANS) contain hundreds of carbon nanotubes, which are one-atom thick sheets of graphene rolled into a tube that have extraordinary mechanical, electrical and thermal properties. Lockheed Martin’s carbon nanostructures are unique because the carbon nanotubes within each flake are all properly aligned, making them good conductors of heat and electricity.

“Lockheed Martin’s carbon nanostructures have many potential applications, but in its powdery form, it cannot be used. It has to be fabricated in a way that keeps the unique properties of the carbon nanotube,” explained Dr. Al Ghaferi. “The challenge we faced was to create something useful with the carbon nanotubes without losing any of their unique properties or disturbing the alignment.”

Dr. Younes said: “Each flake is a carbon nanostructure containing many aligned carbon nanotubes. The alignment of the tubes creates a path for conductivity, much like a wire, making the nanostructure an exceptionally good conductor of electricity.”

The Masdar Institute team mixed the carbon nanotubes with a polymer and their resulting buckypaper, which successfully maintained the alignment of the carbon nanotubes, demonstrated high thermal-electrical conductivity and superior mechanical properties.

“We have a secret recipe for self-aligning the carbon nanotubes within the buckypaper. This self-aligning is key in significantly enhancing the electrical, thermal and mechanical properties of our fabricated buckypapers,” explained Dr. Abu Al-Rub.

Despite their microscopic size – a carbon nanotube’s diameter is about 10,000 times smaller than a human hair – carbon nanotubes’ impact on technology has been huge. At the individual tube level, carbon nanotubes are 200 times stronger, five times more elastic, and five times more electrically conductive than steel.

Because of their extraordinary strength, thermal and electrical properties, and miniscule size, carbon nanotubes can be used in a number of applications, including ultra-thin energy storage devices, smaller and more efficient computer chips, photovoltaic solar cells, flexible electronics, cancer detection, and lightning-resistant coatings on airplanes.

According to a report by Global Industry Analysts Inc., the current global market for nanotubes is pegged at roughly US$5 billion and its market share is growing sharply, reflecting the rising sentiment worldwide in carbon nanotubes’ potential as a wonder technology.

Masdar Institute’s efforts to capitalize on this emerging technology have resulted in several cutting-edge carbon nanotube research projects, including an attempt to create carbon nanotube-strengthened concrete, super capacitors that can hold 50 times more charge, and a membrane that can bind organic micro-pollutants.

As the UAE moves towards a clean energy future, innovations in renewable energy storage systems and other sustainable technologies are crucial for the country’s successful transition, and researchers at Masdar Institute believe that carbon nanotubes will play a huge role in achieving energy sustainability.

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

Processing and property investigation of high-density carbon nanostructured papers with superior conductive and mechanical properties by Hammad Younesa, Rashid Abu Al-Ruba, Md. Mahfuzur Rahmana, Ahmed Dalaqa, Amal Al Ghaferia, Tushar Shahb. Diamond and Related Materials Volume 68, September 2016, Pages 109–117  DOI: http://dx.doi.org/10.1016/j.diamond.2016.06.016

This paper is behind a paywall.

Using fish ‘biowaste’ for self-powered electronics

Researchers in India have found a way to make use of fish ‘biowaste’ according to a Sept. 6, 2016 news item on Nanowerk,

Large quantities of fish are consumed in India on a daily basis, which generates a huge amount of fish “biowaste” materials. In an attempt to do something positive with this biowaste, a team of researchers at Jadavpur University in Koltata, India explored recycling the fish byproducts into an energy harvester for self-powered electronics.

Caption: Waste fish scales (upper left corner) are used to fabricate flexible nanogenerator (lower left) that power up more than 50 blue LEDs (lower right). An enlarged microscopic view of a fish scale shows the well-aligned collagen fibrils (upper right). The possibility of making a fish scale transparent (middle) and rollable (extreme left lower corner) is also illustrated. Credit: Sujoy Kuman Ghosh and Dipankar Mandal/Jadavpur University

Caption: Waste fish scales (upper left corner) are used to fabricate flexible nanogenerator (lower left) that power up more than 50 blue LEDs (lower right). An enlarged microscopic view of a fish scale shows the well-aligned collagen fibrils (upper right). The possibility of making a fish scale transparent (middle) and rollable (extreme left lower corner) is also illustrated. Credit: Sujoy Kuman Ghosh and Dipankar Mandal/Jadavpur University

A Sept. 6, 2016 American Institute of Physics news release on EurekAlert, which originated the news item, describes the research in more detail,

The basic premise behind the researchers’ work is simple: Fish scales contain collagen fibers that possess a piezoelectric property, which means that an electric charge is generated in response to applying a mechanical stress. As the team reports this week in Applied Physics Letters, from AIP Publishing, they were able to harness this property to fabricate a bio-piezoelectric nanogenerator.

To do this, the researchers first “collected biowaste in the form of hard, raw fish scales from a fish processing market, and then used a demineralization process to make them transparent and flexible,” explained Dipankar Mandal, assistant professor, Organic Nano-Piezoelectric Device Laboratory, Department of Physics, at Jadavpur University.

The collagens within the processed fish scales serve as an active piezoelectric element.

“We were able to make a bio-piezoelectric nanogenerator — a.k.a. energy harvester — with electrodes on both sides, and then laminated it,” Mandal said.

While it’s well known that a single collagen nanofiber exhibits piezoelectricity, until now no one had attempted to focus on hierarchically organizing the collagen nanofibrils within the natural fish scales.

“We wanted to explore what happens to the piezoelectric yield when a bunch of collagen nanofibrils are hierarchically well aligned and self-assembled in the fish scales,” he added. “And we discovered that the piezoelectricity of the fish scale collagen is quite large (~5 pC/N), which we were able to confirm via direct measurement.”

Beyond that, the polarization-electric field hysteresis loop and resulting strain-electric field hysteresis loop — proof of a converse piezoelectric effect — caused by the “nonlinear” electrostriction effect backed up their findings.

The team’s work is the first known demonstration of the direct piezoelectric effect of fish scales from electricity generated by a bio-piezoelectric nanogenerator under mechanical stimuli — without the need for any post-electrical poling treatments.

“We’re well aware of the disadvantages of the post-processing treatments of piezoelectric materials,” Mandal noted.

To explore the fish scale collagen’s self-alignment phenomena, the researchers used near-edge X-ray absorption fine-structure spectroscopy, measured at the Raja Ramanna Centre for Advanced Technology in Indore, India.

Experimental and theoretical tests helped them clarify the energy scavenging performance of the bio-piezoelectric nanogenerator. It’s capable of scavenging several types of ambient mechanical energies — including body movements, machine and sound vibrations, and wind flow. Even repeatedly touching the bio-piezoelectric nanogenerator with a finger can turn on more than 50 blue LEDs.

“We expect our work to greatly impact the field of self-powered flexible electronics,” Mandal said. “To date, despite several extraordinary efforts, no one else has been able to make a biodegradable energy harvester in a cost-effective, single-step process.”

The group’s work could potentially be for use in transparent electronics, biocompatible and biodegradable electronics, edible electronics, self-powered implantable medical devices, surgeries, e-healthcare monitoring, as well as in vitro and in vivo diagnostics, apart from its myriad uses for portable electronics.

“In the future, our goal is to implant a bio-piezoelectric nanogenerator into a heart for pacemaker devices, where it will continuously generate power from heartbeats for the device’s operation,” Mandal said. “Then it will degrade when no longer needed. Since heart tissue is also composed of collagen, our bio-piezoelectric nanogenerator is expected to be very compatible with the heart.”

The group’s bio-piezoelectric nanogenerator may also help with targeted drug delivery, which is currently generating interest as a way of recovering in vivo cancer cells and also to stimulate different types of damaged tissues.

“So we expect our work to have enormous importance for next-generation implantable medical devices,” he added.

“Our end goal is to design and engineer sophisticated ingestible electronics composed of nontoxic materials that are useful for a wide range of diagnostic and therapeutic applications,” said Mandal.

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

High-performance bio-piezoelectric nanogenerator made with fish scale by Sujoy Kumar Ghosh and Dipankar Mandal. Appl. Phys. Lett. 109, 103701 (2016); http://dx.doi.org/10.1063/1.4961623

This paper appears to be open access.