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 – utilising 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 utilisation 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.
Figure 1: The bottom image shows a self-standing molybdenum disulfide/graphene composite paper electrode and the top image highlights its layered structure.
Source: 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 per cent to 500 per cent 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:
The researchers are currently working on the commercialisation 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.
Originally published by CleanTechnica. Reproduced with permission.