Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Labs characterize carbon for batteries

15.07.2014

Rice, Lawrence Livermore scientists calculate materials’ potential for use as electrodes

Lithium-ion batteries could benefit from a theoretical model created at Rice University and Lawrence Livermore National Laboratory that predicts how carbon components will perform as electrodes.


New work by scientists at Lawrence Livermore National Laboratory and Rice University details the binding properties of lithium ions to various types of carbon that may be used for lithium-ion batteries. The “universal descriptor” they found has the potential to speed the development of materials for commercialization. (Credit: Yuanyue Liu/Rice University)

The model is based on intrinsic electronic characteristics of materials used as battery anodes. These include the material’s quantum capacitance (the ability of the material to absorb charge) and the material’s absolute Fermi level, which determines how many lithium ions may bond to the electrodes.

Subtle changes in the structure, chemistry and shape of an electrode can significantly alter how strongly lithium ions bond to it and affect a battery’s capacity, voltage and energy density. The researchers found a universal correlation between these properties and a simple quantity they called the “states-filling work”  that should allow scientists to fine-tune electrodes.

The research appears in the journal Physical Review Letters. Lawrence Livermore scientist Brandon Wood and Rice theoretical physicist Boris Yakobson led the study.

Fine-tuning becomes critically important as materials scientists test more 2-D materials like graphene and nanotubes for use as electrodes. The materials offer vast surface area for ions to bind to in a compact package, Yakobson said.

“This work emphasizes the role of quantum capacitance,” he said. “Capacitance in a battery is usually defined by the configuration of your electrodes; people think about this as the distance between the plates.

“But if the plates become very close and the electrodes and electrolyte are tight, then quantum capacitance becomes the limiting parameter.”

“The Fermi level of the electrode material is also important,” said Rice graduate student Yuanyue Liu, the paper’s lead author. “The lower it is, the stronger lithium will bind.”

Liu and Lawrence Livermore staff scientist Brandon Wood were looking for a “descriptor,” a characteristic that would capture the essential physics of interactions between lithium and a variety of carbon materials, including pristine, defective and strained graphene, planar carbon clusters, nanotubes, carbon edges and multilayer stacks.

“That descriptor turned out to be the ‘states-filling work’ – the work required to fill previously unoccupied electronic states within the electrode,” Liu said.

“Generally speaking, a descriptor is an intermediate property or parameter that doesn’t give you what you really want to know, but correlates well with the material’s final performance,” Yakobson said.

“The descriptor connects to properties that may be quite complex,” he said. “For instance, you can judge people’s physical strength by how tall they are or by weight. That’s easy to measure. It doesn’t exactly tell you how strong the person will be, but it gives you some idea.”

Based on the descriptor, the researchers were able to evaluate various carbon materials. Specifically, they found materials like defective or curved graphene were good candidates for anodes, as their energy profiles allowed more lithium ions to bind. Ultimately, their work suggested a set of binding guidelines for carbon anodes.

“These allow us to quickly evaluate material performance without doing electrochemical tests or expensive computations,” Liu said.

“The fact that our descriptor predicts the performance of such a wide variety of materials is surprising,” Wood said. “It means the underlying physics is really very similar, even if the structure, morphology, or chemistry differs from one candidate to the next. It’s really a very simple and elegant finding that could accelerate design and discovery.”

Yakobson noted the work is in line with the Materials Genome Initiative (MGI), which aims to double the speed and reduce the cost of developing advanced materials by providing these kinds of tools. Earlier this year, Rice’s George R. Brown School of Engineering hosted a workshop on the MGI initiative, one of four held around the country.

Yakobson is Rice’s Karl F. Hasselmann Professor of Materials Science and NanoEngineering, a professor of chemistry and a member of the Richard E. Smalley Institute for Nanoscale Science and Technology.

Lawrence Livermore National Laboratory and the Department of Energy supported the research.

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice’s undergraduate student-to-faculty ratio is just over 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for “best value” among private universities by Kiplinger’s Personal Finance.

David Ruth | Eurek Alert!

Further reports about: MGI batteries electrode electrodes graphene ions materials properties

More articles from Power and Electrical Engineering:

nachricht New high energy density automotive battery system from Fraunhofer IISB and international partners
25.08.2015 | Fraunhofer-Gesellschaft

nachricht New research may enhance display & LED lighting technology
10.08.2015 | University of Illinois College of Engineering

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

Im Focus: Self-healing landscape: landslides after earthquake

In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.

These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...

Im Focus: FIC Proteins Send Bacteria Into Hibernation

Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.

For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...

Im Focus: Fraunhofer IPA develops prototype of intelligent care cart

It comes when called, bringing care utensils with it and recording how they are used: Fraunhofer IPA is developing an intelligent care cart that provides care staff with physical and informational support in their day-to-day work. The scientists at Fraunhofer IPA have now completed a first prototype. In doing so, they are continuing in their efforts to improve working conditions in the care sector and are developing solutions designed to address the challenges of demographic change.

Technical assistance systems can improve the difficult working conditions in residential nursing homes and hospitals by helping the staff in their work and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Interstellar seeds could create oases of life

28.08.2015 | Physics and Astronomy

An ounce of prevention: Research advances on 'scourge' of transplant wards

28.08.2015 | Health and Medicine

Fish Oil-Diet Benefits May be Mediated by Gut Microbes

28.08.2015 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>