Glass coating improves battery performance

Scientists have created nano-sized sulphur particles coated in silica (glass) to be used in Lithium-sulphur batteries.

The new technique would enhance the battery life and performance manifold. Lithium-sulphur batteries can produce up to 10 times more energy than conventional batteries.

"However, one of the main problems with these batteries is the tendency for lithium and sulphur reaction products, called lithium polysulfides, to dissolve in the battery's electrolyte and travel to the opposite electrode permanently," said the researchers.

This causes the battery's capacity to decrease over its lifetime.

"Our biggest challenge was to optimise the process to deposit SiO2 - not too thick, not too thin, about the thickness of a virus," said researcher Mihri Ozkan of the University of California, Riverside.

Researchers prevented this "polysulfide shuttling" phenomenon by creating the nano-sized sulphur particles and coating them in silica (SiO2), otherwise known as glass.

The team used an organic precursor to construct the trapping barrier.

They found that silica-caged sulphur particles provided a substantially higher battery performance.

"We have decided to incorporate mildly reduced graphene oxide (mrGO), a close relative of graphene, as a conductive additive in cathode material design to provide mechanical stability to the glass caged structures," said co-investigator Cengiz Ozkan of the same university.

"Incorporation of mrGO serves the system well in holding the polysulfide traps in place. Our new cathode design allows sulphur to expand and contract, and be harnessed," Cengiz Ozkan said.

The work was published online in the journal Nanoscale.