Yarns of niobium nanowire can make supercapacitors to provide a surge of energy when it’s needed
Wearable electronic devices for health and fitness monitoring are a rapidly growing area of consumer electronics; one of their biggest limitations is the capacity of their tiny batteries to deliver enough power to transmit data. Now, researchers at MIT and in Canada have found a promising new approach to delivering the short but intense bursts of power needed by such small devices.
The key is a new approach to making supercapacitors — devices that can store and release electrical power in such bursts, which are needed for brief transmissions of data from wearable devices such as heart-rate monitors, computers, or smartphones, the researchers say. They may also be useful for other applications where high power is needed in small volumes, such as autonomous microrobots.
The new approach uses yarns, made from nanowires of the element niobium, as the electrodes in tiny supercapacitors (which are essentially pairs of electrically conducting fibers with an insulator between). The concept is described in a paper in the journal ACS Applied Materials and Interfaces by MIT professor of mechanical engineering Ian W. Hunter, doctoral student Seyed M. Mirvakili, and three others at the University of British Columbia.
Nanotechnology researchers have been working to increase the performance of supercapacitors for the past decade. Among nanomaterials, carbon-based nanoparticles — such as carbon nanotubes and graphene — have shown promising results, but they suffer from relatively low electrical conductivity, Mirvakili says.
In this new work, he and his colleagues have shown that desirable characteristics for such devices, such as high power density, are not unique to carbon-based nanoparticles, and that niobium nanowire yarn is a promising an alternative.
“Imagine you’ve got some kind of wearable health-monitoring system,” Hunter says, “and it needs to broadcast data, for example using Wi-Fi, over a long distance.” At the moment, the coin-sized batteries used in many small electronic devices have very limited ability to deliver a lot of power at once, which is what such data transmissions need.
“Long-distance Wi-Fi requires a fair amount of power,” says Hunter, the George N. Hatsopoulos Professor in Thermodynamics in MIT’s Department of Mechanical Engineering, “but it may not be needed for very long.” Small batteries are generally poorly suited for such power needs, he adds.
“We know it’s a problem experienced by a number of companies in the health-monitoring or exercise-monitoring space. So an alternative is to go to a combination of a battery and a capacitor,” Hunter says: the battery for long-term, low-power functions, and the capacitor for short bursts of high power. Such a combination should be able to either increase the range of the device, or — perhaps more important in the marketplace — to significantly reduce size requirements.
The new nanowire-based supercapacitor exceeds the performance of existing batteries, while occupying a very small volume. “If you’ve got an Apple Watch and I shave 30 percent off the mass, you may not even notice,” Hunter says. “But if you reduce the volume by 30 percent, that would be a big deal,” he says: Consumers are very sensitive to the size of wearable devices.
The innovation is especially significant for small devices, Hunter says, because other energy-storage technologies — such as fuel cells, batteries, and flywheels — tend to be less efficient, or simply too complex to be practical when reduced to very small sizes. “We are in a sweet spot,” he says, with a technology that can deliver big bursts of power from a very small device.
Ideally, Hunter says, it would be desirable to have a high volumetric power density (the amount of power stored in a given volume) and high volumetric energy density (the amount of energy in a given volume). “Nobody’s figured out how to do that,” he says. However, with the new device, “We have fairly high volumetric power density, medium energy density, and a low cost,” a combination that could be well suited for many applications.
Niobium is a fairly abundant and widely used material, Mirvakili says, so the whole system should be inexpensive and easy to produce. “The fabrication cost is cheap,” he says. Other groups have made similar supercapacitors using carbon nanotubes or other materials, but the niobium yarns are stronger and 100 times more conductive. Overall, niobium-based supercapacitors can store up to five times as much power in a given volume as carbon nanotube versions.
Niobium also has a very high melting point — nearly 2,500 degrees Celsius — so devices made from these nanowires could potentially be suitable for use in high-temperature applications.
In addition, the material is highly flexible and could be woven into fabrics, enabling wearable forms; individual niobium nanowires are just 140 nanometers in diameter — 140 billionths of a meter across, or about one-thousandth the width of a human hair.
Read more: Tiny wires could provide a big energy boost
The Latest on: Nanowire supercapacitors
via Google News
The Latest on: Nanowire supercapacitors
- Ag-fiber/graphene hybrid electrodes for highly flexible and transparent optoelectronic deviceson March 20, 2020 at 3:05 am
Transparent conducting electrodes (TCEs) have attracted considerable attention towards the development of flexible optoelectronic devices. In this study, mixed-dimensional TCEs are fabricated ...
- Nanobiohybrids: Materials approaches for bioaugmentationon March 18, 2020 at 11:19 am
1 School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia. 2 Graduate School of Biomedical Engineering, and Australian Centre for NanoMedicine, University of New ...
- Journal of nanoscience and nanotechnologyon March 16, 2020 at 5:00 pm
Effect of Structural Transition on Magnetic Properties of Fe-Doped Nanocrystalline La0.7Te0.3Mn1-xFexO₃ (x 0.2, 0.4 and 0.5).
- Viewpoint: Spin Control with a Topological Semimetalon March 16, 2020 at 8:23 am
Figure 2: Scheme of the circuit used by Liao and co-workers, in which a Dirac semimetal nanowire (long grey cylinder) is contacted by four electrodes. (Top) “Local” configuration: a current is ...
- Scientists realize a broadly tunable laser of a single perovskite nanowireon March 4, 2020 at 5:32 am
(Nanowerk News) Semiconductor nanowire lasers with a broadband and continuous wavelength tunability are highly desirable for integrated photonic and optoelectronic devices. Despite tremendous efforts ...
- Presentation by PARC, a Xerox Companyon February 26, 2020 at 7:14 pm
printed nanowire) semiconductors. PARC's clients include display manufacturers, consumer electronics firms, IT companies, government agencies, and materials suppliers to the printed and flexible ...
- Bringing the green revolution to electronicson February 25, 2020 at 9:08 am
For example, one FET biosensor incorporated a calmodulin-modified nanowire transistor. Calmodulin is an acidic protein that can bind to different molecules, so the biosensor could be used for ...
- Synopsis: Improving Models of How Supercapacitors Chargeon February 19, 2020 at 4:00 pm
A new model more accurately predicts the charging time of real supercapacitors by better accounting for the structure of the device’s porous electrodes. Supercapacitors are useful in situations that ...
- regulation promoted performance in aon February 19, 2020 at 5:54 am
Figure S1. XRD pattern of NP-0, NP-1, NP-2, NP-3, NP-4, NP-6 and NP-9. Figure S1 shows the XRD patterns of the precursor located on the Ni foam substrate. 3 mmol NH4F and setting the run time at: (a, ...
- A big step for Ecuadoron April 4, 2019 at 4:55 am
Among them, Vincent Meunier (Oak Ridge National Laboratory, USA) discussed models of ion dynamics and its effects in the performance of supercapacitors ... between a cobalt nanowire and a carbon ...
via Bing News