Research & Development World

  • Home Page
  • Topics
    • Aerospace
    • Archeology
    • Automotive
    • Biotech
    • Chemistry
    • COVID-19
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Market Pulse
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
      • Software
    • Semiconductors
  • 2021 R&D 100 Award Winners
    • R&D 100 Awards
    • 2020 Winners
    • Winner Archive
  • Resources
    • Digital Issues
    • Podcasts
    • Subscribe
  • Global Funding Forecast
  • Webinars

Disordered materials hold promise for better batteries

By R&D Editors | January 10, 2014

Conventional layered lithium and transition metal cathode material (top) and the new disordered material studied by researchers at MIT (bottom) as seen through a scanning tunneling electron microscope. Inset images show diagrams of the different structures in these materials. (In the disordered material, the blue lines show the pathways that allow lithium ions to traverse the material.) Image courtesy of the researchers. Lithium batteries, with their exceptional ability to store power per a given weight, have been a major focus of research to enable use in everything from portable electronics to electric cars. Now researchers at Massachusetts Institute of Technology (MIT) and Brookhaven National Laboratory have found a whole new avenue for such research: the use of disordered materials, which had generally been considered unsuitable for batteries.

In a rechargeable lithium-based battery, lithium ions are pulled out of the battery’s cathode during the charging process, and returned to the cathode as power is drained. But these repeated round trips can cause the electrode material to shrink and expand, leading to cracks and degrading performance over time.

In today’s lithium batteries, those cathodes are usually made of an orderly crystalline material, sometimes in a layered structure. When slight deviations from that perfect order are introduced, the battery’s efficiency generally goes down—so disordered materials have mostly been ignored in the search for improved battery materials.

But it turns out this correlation is far from universal: Certain kinds of disorder can provide a significant boost in cathode performance, the researchers have found through a combination of computer modeling and laboratory experiments. These surprising findings are reported in Science, in a paper by MIT graduate student Jinhyuk Lee, prof. of materials science and engineering Gerbrand Ceder and four others.

Ceder describes the materials that can release and then reabsorb the lithium ions as a kind of “reversible sponge.” In today’s batteries, the cathodes are striated materials, made up of lithium layers alternating with oxides of transition metals. Scientists had thought the layering was necessary to provide a pathway for lithium to pass in and out of the cathodes without bumping into the transition metal oxide layer—“a channel with nothing in the way,” as Ceder says.

Moreover, disorder “usually significantly reduces the lithium ion mobility,” Ceder says—and high mobility is essential for an efficient rechargeable battery.

But it turns out that a significant excess of lithium in the material changes things dramatically. In the traditional ordered structure, there is an exact balance between the number of lithium and metal atoms. “But if you get enough of a lithium excess,” Ceder says, “you get new channels, and they can take over from the channels you close off.”

While the disordered material with excess lithium produces irregular pathways, it turns out that these nevertheless can still act as efficient channels for the lithium ions. But such a material offers an extra bonus: While the irregular channels let lithium pass just as easily as it does in a layered material, in the disordered material the lithium ions don’t push the layers out of shape.

The new material—in these experiments, lithium molybdenum chromium oxide—“has a very high dimensional stability,” Ceder says. In most other lithium cathode materials, “as you pull the lithium in and out, it changes dimension, swelling or contracting.” This swelling and contracting “causes all sorts of problems,” including fatigue that can lead to cracking, he says.

While the dimensional changes in layered materials can be as much as 5 to 10%, he says, in the new disordered material it is only about 0.1%—“virtually zero.”

Ceder stresses that his group’s analysis of this specific compound “shows a new direction that we can take” in searching for even better materials, opening a whole new category of possibilities that had previously been ignored. While lithium molybdenum chromium oxide can hold and release significantly more lithium than existing materials, it produces a lower voltage—meaning its overall performance is about the same as that of existing materials, he says.

Many new materials take decades to move from the laboratory to useful applications, but “we’re hopeful we can do this in one or two years, to discover something better,” Ceder says—most likely by using computational tools such as the Materials Project, which he co-founded.

Source: Massachusetts Institute of Technology

Related Articles Read More >

Argonne webinar to explore the challenges of recycling lithium-ion batteries and solutions
VARTA presents microbattery product portfolio at COMPUTEX 2022
SOLiTHOR seeds $10.6M to develop a new solid-state battery cell technology
Growing zinc battery initiative welcomes startup Zēlos Energy
2021 R&D Global Funding Forecast

Need R&D World news in a minute?

We Deliver!
R&D World Enewsletters get you caught up on all the mission critical news you need in research and development. Sign up today.
Enews Signup

R&D World Digital Issues

February 2020 issue

Browse the most current issue of R&D World and back issues in an easy to use high quality format. Clip, share and download with the leading R& magazine today.

Research & Development World
  • Subscribe to R&D World Magazine
  • Enews Sign Up
  • Contact Us
  • About Us
  • Drug Discovery & Development
  • Pharmaceutical Processing
  • 2022 Global Funding Forecast

Copyright © 2022 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search R&D World

  • Home Page
  • Topics
    • Aerospace
    • Archeology
    • Automotive
    • Biotech
    • Chemistry
    • COVID-19
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Market Pulse
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
      • Software
    • Semiconductors
  • 2021 R&D 100 Award Winners
    • R&D 100 Awards
    • 2020 Winners
    • Winner Archive
  • Resources
    • Digital Issues
    • Podcasts
    • Subscribe
  • Global Funding Forecast
  • Webinars