Published on February 3rd, 2014 | by James Ayre


Sodium-Ion Batteries Receive Boost From Graphene Nanosheet Composite Paper

February 3rd, 2014 by  

Sodium-ion batteries are now one step closer to being a reality, thanks to new research from Kansas State University. Researchers there have developed a new composite paper — utilizing graphene nano-sheets — that can be used as a negative electrode in sodium-ion batteries.

The “breakthrough,” as the researchers have referred to it, is based on the utilization of a material created from interleaved layers of molybdenum disulfide and graphene nanosheets — this research is the first to show that such a paper can function as both an active material to efficiently store sodium atoms and also as a flexible current collector.

A Kansas State University engineer has made a breakthrough in rechargeable battery applications. The bottom image shows a self-standing molybdenum disulfide/graphene composite paper electrode and the top image highlights its layered structure. Image Credit: Gurpreet Singh

A Kansas State University engineer has made a breakthrough in rechargeable battery applications. The bottom image shows a self-standing molybdenum disulfide/graphene composite paper electrode and the top image highlights its layered structure.
Image Credit: Gurpreet Singh

“Most negative electrodes for sodium-ion batteries use materials that undergo an ‘alloying’ reaction with sodium,” explained researcher Gurpreet Singh, an assistant professor of mechanical and nuclear engineering. “These materials can swell as much as 400% to 500% as the battery is charged and discharged, which may result in mechanical damage and loss of electrical contact with the current collector.”

“Molybdenum disulfide, the major constituent of the paper electrode, offers a new kind of chemistry with sodium ions, which is a combination of intercalation and a conversion-type reaction,” Singh continued. “The paper electrode offers stable charge capacity of 230 mAh.g-1, with respect to total electrode weight. Further, the interleaved and porous structure of the paper electrode offers smooth channels for sodium to diffuse in and out as the cell is charged and discharged quickly. This design also eliminates the polymeric binders and copper current collector foil used in a traditional battery electrode.”

Kansas State University provides more:

For the latest research, the engineers created a large-area composite paper that consisted of acid-treated layered molybdenum disulfide and chemically modified graphene in an interleaved structured. The research marks the first time that such a flexible paper electrode was used in a sodium-ion battery as an anode that operates at room temperature. Most commercial sodium-sulfur batteries operate close to 300 degrees Celsius, Singh said.

Singh said the research is important for two reasons:

1. Synthesis of large quantities of single or few-layer-thick 2-D materials is crucial to understanding the true commercial potential of materials such as transition metal dichalcogenides, or TMD, and graphene.

2. Fundamental understanding of how sodium is stored in a layered material through mechanisms other than the conventional intercalation and alloying reaction. In addition, using graphene as the flexible support and current collector is crucial for eliminating the copper foil and making lighter and bendable rechargeable batteries. In contrast to lithium, sodium supplies are essentially unlimited and the batteries are expected to be a lot cheaper.

“From the synthesis point of view, we have shown that certain transition metal dichalcogenides can be exfoliated in strong acids,” Singh stated. “This method should allow synthesis of gram quantities of few-layer-thick molybdenum disulfide sheets, which is very crucial for applications such as flexible batteries, supercapacitors, and polymer composites. For such applications, TMD flakes that are a few atoms thick are sufficient. Very high-quality single-layer flakes are not a necessity.”

The researchers are currently working on the commercialization of the technology, as well as continuing to explore lithium and sodium storage possibilities in other nanomaterials.

The new research is detailed in a paper just published in the journal ACS Nano.

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's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

  • Charles

    I just have one question that I cant seem to get an answer to anywhere. Who is producing these batteries here in the US? Is it just Aquoin and Sumitomo who you have to submit a whole bunch of information to? I have a project that would be complete with the Sodium Ion Battery. Please help.

  • Jean-Baptiste Segard

    What’s the expected time to maket of large capacity batteries designed for EVs ?

    • Jong-Hee Park

      Seems such batteries are designed for Cell-Phone or laptop computers than the 25-kw power EV due to the required anode material. 25 kw power can be a big material is required. 25Kw-h meets near 21.5 kg of Na?? may be 60 mph (as 25 kw) assumed, if 100-200 miles then 35.7-71.5 kg Na to be loaded. If Li 10.9-21.7 kg for the powerful driving in 100-200 miles….is any one can double check on the loading of Na or Li those I roughly calculated? Thanks.

  • JamesWimberley

    “Sodium supplies are essentially unlimited ..” True. But molybdenum is fairly scarce. Let’s hope the design can be made to work without it.
    The press release doesn’t explain how Professor Singh made such large sheets of graphene.

    • A Real Libertarian

      “For such applications, [transition metal dichalcogenides] flakes that are a few atoms thick are sufficient”

      That’s where the molybdenum is.

      I doubt it takes much.

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