Lithium-sulphur batteries are of great commercial interest because their specific energy densities are considerably greater than those of their established cousin -  lithium ion batteries, which are extensively used currently.

The novel cathode for rechargeable lithium-sulphur batteries features a thin "wrap sandwich" sheet of graphene around a multi-functional sulphur electrode. Graphene is pure carbon in the form of a very thin, nearly transparent sheet. It is just one atom thick.

Vasant Kumar from the University of Cambridge and professor Renjie Chen at the Beijing Institute of Technology designed a multi-functional sulphur cathode at the nano-level to address performance related issues such as low efficiency and capacity degradation.

"Our carbon scaffold acts as a physical barrier to confine the active materials within its porous structure. This leads to improved cycling stability and high efficiency," the authors said.

They also discovered that by further wrapping the sulphur-carbon energy storage unit within a thin sheet of flexible graphene speeds the transport of electrons and ions.

This work provides a "basic, but flexible, approach to both enhance the use of sulphur and improve the cycle stability of batteries". The paper appeared in the journal APL Materials.