A car powered by its own body panels could soon be driving on our roads after a breakthrough in nanotechnology research by a Queensland University of Technology (QUT) team.
Researchers have developed lightweight “supercapacitors” that can be combined with regular batteries to dramatically boost the power of an electric car.
The discovery was made by Postdoctoral Research Fellow Dr Jinzhang Liu, Professor Nunzio Motta and PhD researcher Marco Notarianni, from QUT’s Science and Engineering Faculty – Institute for Future Environments, and PhD researcher Francesca Mirri and Professor Matteo Pasquali, from Rice University in Houston, in the United States.
QUT’s Professor Nunzio Motta with one of the university’s powerful nanotechnology microscopes.
The supercapacitors – a “sandwich” of electrolyte between two all-carbon electrodes – were made into a thin and extremely strong film with a high power density.
The film could be embedded in a car’s body panels, roof, doors, bonnet and floor – storing enough energy to turbocharge an electric car’s battery in just a few minutes.
“Vehicles need an extra energy spurt for acceleration, and this is where supercapacitors come in. They hold a limited amount of charge, but they are able to deliver it very quickly, making them the perfect complement to mass-storage batteries,” he said.
“Supercapacitors offer a high power output in a short time, meaning a faster acceleration rate of the car and a charging time of just a few minutes, compared to several hours for a standard electric car battery.”
Dr Liu said currently the “energy density” of a supercapacitor is lower than a standard lithium ion (Li-Ion) battery, but its “high power density”, or ability to release power in a short time, is “far beyond” a conventional battery.
“Supercapacitors are presently combined with standard Li-Ion batteries to power electric cars, with a substantial weight reduction and increase in performance,” he said.
“In the future, it is hoped the supercapacitor will be developed to store more energy than a Li-Ion battery while retaining the ability to release its energy up to 10 times faster – meaning the car could be entirely powered by the supercapacitors in its body panels.
“After one full charge this car should be able to run up to 500km – similar to a petrol-powered car and more than double the current limit of an electric car.”
Dr Liu said the technology would also potentially be used for rapid charges of other battery-powered devices.
“For example, by putting the film on the back of a smart phone to charge it extremely quickly,” he said.
The discovery may be a game-changer for the automotive industry, with significant impacts on financial, as well as environmental, factors.
“We are using cheap carbon materials to make supercapacitors and the price of industry scale production will be low,” Professor Motta said.
“The price of Li-Ion batteries cannot decrease a lot because the price of Lithium remains high. This technique does not rely on metals and other toxic materials either, so it is environmentally friendly if it needs to be disposed of.”
Rice University scientists who want to gain an edge in energy production and storage report they have found it in molybdenum disulfide.
The Rice lab of chemist James Tour has turned molybdenum disulfide’s two-dimensional form into a nanoporous film that can catalyze the production of hydrogen or be used for energy storage.
The versatile chemical compound classified as a dichalcogenide is inert along its flat sides, but previous studies determined the material’s edges are highly efficient catalysts for hydrogen evolution reaction (HER), a process used in fuel cells to pull hydrogen from water.
Tour and his colleagues have found a cost-effective way to create flexible films of the material that maximize the amount of exposed edge and have potential for a variety of energy-oriented applications.
The Rice research appears in the journal Advanced Materials.
A new material developed at Rice University based on molybdenum disulfide exposes as much of the edge as possible, making it efficient as both a catalyst for hydrogen production and for energy storage. Credit: Tour Group/Rice University
Molybdenum disulfide isn’t quite as flat as graphene, the atom-thick form of pure carbon, because it contains both molybdenum and sulfur atoms. When viewed from above, it looks like graphene, with rows of ordered hexagons. But seen from the side, three distinct layers are revealed, with sulfur atoms in their own planes above and below the molybdenum.
This crystal structure creates a more robust edge, and the more edge, the better for catalytic reactions or storage, Tour said.
“So much of chemistry occurs at the edges of materials,” he said. “A two-dimensional material is like a sheet of paper: a large plain with very little edge. But our material is highly porous. What we see in the images are short, 5- to 6-nanometer planes and a lot of edge, as though the material had bore holes drilled all the way through.”
The new film was created by Tour and lead authors Yang Yang, a postdoctoral researcher; Huilong Fei, a graduate student; and their colleagues. It catalyzes the separation of hydrogen from water when exposed to a current. “Its performance as a HER generator is as good as any molybdenum disulfide structure that has ever been seen, and it’s really easy to make,” Tour said.
While other researchers have proposed arrays of molybdenum disulfide sheets standing on edge, the Rice group took a different approach. First, they grew a porous molybdenum oxide film onto a molybdenum substrate through room-temperature anodization, an electrochemical process with many uses but traditionally employed to thicken natural oxide layers on metals.
The film was then exposed to sulfur vapor at 300 degrees Celsius (572 degrees Fahrenheit) for one hour. This converted the material to molybdenum disulfide without damage to its nano-porous sponge-like structure, they reported.
The films can also serve as supercapacitors, which store energy quickly as static charge and release it in a burst. Though they don’t store as much energy as an electrochemical battery, they have long lifespans and are in wide use because they can deliver far more power than a battery. The Rice lab built supercapacitors with the films; in tests, they retained 90 percent of their capacity after 10,000 charge-discharge cycles and 83 percent after 20,000 cycles.
“We see anodization as a route to materials for multiple platforms in the next generation of alternative energy devices,” Tour said. “These could be fuel cells, supercapacitors and batteries. And we’ve demonstrated two of those three are possible with this new material.”
Two years ago, Prof. Eshel Ben-Jacob of Tel Aviv University’s School of Physics and Astronomy and Rice University’s Center for Theoretical Biological Physics made the startling discovery that cancer, like an enemy hacker in cyberspace, targets the body’s communication network to inflict widespread damage on the entire system. Cancer, he found, possessed special traits for cooperative behavior and used intricate communication to distribute tasks, share resources, and make decisions.
The “Cyberwar” Against Cancer Gets a Boost from Intelligent Nanocarriers: TAU researcher advances novel strategy to fight cancer by shoring up the immune system
New York, NY | Posted on October 7th, 2014
In research published in the Early Edition of the Proceedings of the National Academy of Sciences, Prof. Ben-Jacob and researchers from Rice University and the University of Texas M.D. Anderson Cancer Center, the leading cancer treatment center in the U.S., offer new insight into the lethal interaction between cancer cells and the immune system’s communications network. Prof. Ben-Jacob and the study co-authors developed a computer program that models a specific channel of cell-to-cell communication involving exosomes (nanocarriers with crucial cellular “intelligence”) that both cancer and immune cells harness to communicate with other cells.
“Recent research has found that cancer is already adept at using a kind of ‘cyberwarfare’ against the immune system. We studied the interplay between cancer and the immune system to see how we might be able to shift the balance against cancer,” said Prof. Ben-Jacob, noting a difference between the innate and the adaptive qualities of the immune system. “In the beginning, cancer is inhibited by the body’s innate immunity. But once cancer escapes the immunity, there is a race between the progression of cancer and the ability of the adaptive immune system to recognize and act against it.”
Cyberwarfare of the body
“What we are dealing with is cyberwarfare, pure and simple. Cancer uses the immune systems’ own communications network to attack not the soldiers but the generals that are coordinating the body’s defense,” said Prof. Ben-Jacob.
To better understand the role of exosome-mediated cell-to-cell communication in the battle between cancer and the immune system, the researchers created a computer model that captured the exosomal exchange between cancer cells, dendritic cells, and the other cells in the immune system.
The new model is based on earlier research, which showed that dendritic cells, mediators between the body’s innate and adaptive immune systems (the former protects against all threats at all times and the latter guards more efficiently against specific, established dangers), employed exosomes to fulfil their task. The researchers discovered that, overtaken by cancer, these nanocarriers, which contain such vital components as signaling proteins, RNA snippets, and microRNAs, can command cells to change their tasks, placing the entire system at risk.
Finding a better balance between the strong and the weak
According to the new research, three possible cancer states can exist: strong, intermediary, and weak. The intermediary state — in which cancer is neither strong nor weak and in which the immune system is on high alert — could be the key to a new therapeutic approach with reduced side effects. Prof. Ben-Jacob believes it is possible to force cancer from a strong to moderate state, and then from a moderate to weak state, by alternating cycles of radiation or chemotherapy with immune-boosting treatments.
“Our first important discovery is that this situation is due to the exosome-based cyberwar between cancer and the immune system,” said Prof. Ben-Jacob. “Without exosomes, the two possible states are only strong-weak and weak-strong. With exosomes, an intermediary state opens a new way to treat cancer using very a different approach.”
Prof. Ben-Jacob likened the exchange to a tug-of-war between cancer and the immune system. “The challenge is to be familiar with the battlefield so that we can manipulate cancer therapies to change the balance in favor of the immune system. When cancer is detected, it is almost always in the context of a cancer-immunity competition,” said Prof. Ben-Jacob. “We showed that the way to stop and reverse tumor progression without causing strong side effects is an individualized approach of mixed treatments — i.e., four days of radiation followed by a few days of immune system boosting, followed again by four days of radiation, and so on. If provided in the right order, the treatments could indeed shift the balance toward the immune system’s ‘victory’ in reducing the cancer to the moderate-strong state.”
The study was supported by the Cancer Prevention and Research Institute of Texas, the National Science Foundation, and the Tauber Family Funds.
Carbon nanotubes serve as bridges that allow electrical signals to pass unhindered through new pediatric heart-defect patches invented at Rice University and Texas Children’s Hospital.
A team led by bioengineer Jeffrey Jacot and chemical engineer and chemist Matteo Pasquali created the patches infused with conductive single-walled carbon nanotubes. The patches are made of a sponge-like bioscaffold that contains microscopic pores and mimics the body’s extracellular matrix.
The nanotubes overcome a limitation of current patches in which pore walls hinder the transfer of electrical signals between cardiomyocytes, the heart muscle’s beating cells, which take up residence in the patch and eventually replace it with new muscle.
The work appears this month in the American Chemical Society journal ACS Nano. The researchers said their invention could serve as a full-thickness patch to repair defects due to Tetralogy of Fallot, atrial and ventricular septal defects and other defects without the risk of inducing abnormal cardiac rhythms.
Three images reveal the details of heart-defect patches created at Rice University and Texas Children’s Hospital. At top, three otherwise identical patches darken with greater concentrations of carbon nanotubes, which improve electrical
The original patches created by Jacot’s lab consist primarily of hydrogel and chitosan, a widely used material made from the shells of shrimp and other crustaceans. The patch is attached to a polymer backbone that can hold a stitch and keep it in place to cover a hole in the heart. The pores allow natural cells to invade the patch, which degrades as the cells form networks of their own. The patch, including the backbone, degrades in weeks or months as it is replaced by natural tissue.
Researchers at Rice and elsewhere have found that once cells take their place in the patches, they have difficulty synchronizing with the rest of the beating heart because the scaffold mutes electrical signals that pass from cell to cell. That temporary loss of signal transduction results in arrhythmias.
Living heart cells called ventricular myocytes cultured in nanotube-infused hydrogel beat in an experiment by Rice University and Texas Children’s scientists, who are creating patches to repair pediatric heart defects. Credit: Jacot Lab/Rice University
Nanotubes can fix that, and Jacot, who has a joint appointment at Rice and Texas Children’s, took advantage of the surrounding collaborative research environment.
“This stemmed from talking with Dr. Pasquali’s lab as well as interventional cardiologists in the Texas Medical Center,” Jacot said. “We’ve been looking for a way to get better cell-to-cell communications and were concentrating on the speed of electrical conduction through the patch. We thought nanotubes could be easily integrated.”
Nanotubes enhance the electrical coupling between cells that invade the patch, helping them keep up with the heart’s steady beat. “When cells first populate a patch, their connections are immature compared with native tissue,” Jacot said. The insulating scaffold can delay the cell-to-cell signal further, but the nanotubes forge a path around the obstacles.
Jacot said the relatively low concentration of nanotubes—67 parts per million in the patches that tested best—is key. Earlier attempts to use nanotubes in heart patches employed much higher quantities and different methods of dispersing them.
Jacot’s lab found a component they were already using in their patches – chitosan – keeps the nanotubes spread out. “Chitosan is amphiphilic, meaning it has hydrophobic and hydrophilic portions, so it can associate with nanotubes (which are hydrophobic) and keep them from clumping. That’s what allows us to use much lower concentrations than others have tried.”
Because the toxicity of carbon nanotubes in biological applications remains an open question, Pasquali said, the fewer one uses, the better. “We want to stay at the percolation threshold, and get to it with the fewest nanotubes possible,” he said. “We can do this if we control dispersion well and use high-quality nanotubes.”
The patches start as a liquid. When nanotubes are added, the mixture is shaken through sonication to disperse the tubes, which would otherwise clump, due to van der Waals attraction. Clumping may have been an issue for experiments that used higher nanotube concentrations, Pasquali said.
The material is spun in a centrifuge to eliminate stray clumps and formed into thin, fingernail-sized discs with a biodegradable polycaprolactone backbone that allows the patch to be sutured into place. Freeze-drying sets the size of the discs’ pores, which are large enough for natural heart cells to infiltrate and for nutrients and waste to pass through.
As a side benefit, nanotubes also make the patches stronger and lower their tendency to swell while providing a handle to precisely tune their rate of degradation, giving hearts enough time to replace them with natural tissue, Jacot said.
“If there’s a hole in the heart, a patch has to take the full mechanical stress,” he said. “It can’t degrade too fast, but it also can’t degrade too slow, because it would end up becoming scar tissue. We want to avoid that.”
Pasquali noted that Rice’s nanotechnology expertise and Texas Medical Center membership offers great synergy. “This is a good example of how it’s much better for an application person like Dr. Jacot to work with experts who know how to handle nanotubes, rather than trying to go solo, as many do,” he said. “We end up with a much better control of the material. The converse is also true, of course, and working with leaders in the biomedical field can really accelerate the path to adoption for these new materials.”
More information: “Biocompatible Carbon Nanotube – Chitosan Cardiac Scaffold Matching the Electrical Conductivity of the Heart.” Seokwon Pok , Flavia Vitale , Shannon L. Eichmann , Omar M. Benavides , Matteo Pasquali , and Jeffrey G Jacot ACS Nano, Just Accepted Manuscript DOI: 10.1021/nn503693h