Layered approach leads to composite paper electrode

Gurpreet Singh, assistant professor of mechanical and nuclear engineering, and his student researchers are said to be the first to demonstrate that a composite paper, made of interleaved molybdenum disulphide and graphene nanosheets, can be an active material to efficiently store sodium atoms and a flexible current collector.

Singh said in a statement: ‘Most negative electrodes for sodium-ion batteries use materials that undergo an ‘alloying’ reaction with sodium.

‘These materials can swell as much as 400 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 disulphide, 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.

‘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.’