New gel-like coating may boost lithium-sulphur battery life

A worker takes samples of lithium carbonate processed from the Rockwood Lithium mine on the Atacama salt flat, the largest lithium deposit currently in production, in Antofagasta, northern Chile January 14, 2013. Far from the soy and cattle that dominate its vast fertile pampas, Argentina harbors another valuable commodity that is rocketing in price and demand and luring newly welcomed foreign investors. Lithium, the so-called "white petroleum", drives much of the modern world. It forms a small but essentially irreplaceable component of rechargeable batteries, used in consumer devices like mobile phones and electric cars. It also has pharmaceutical and other applications. Picture taken January 14, 2013. REUTERS/Ivan Alvarado - RTSAHGM

Scientists have developed an ultra-thin coating material that may potentially improve the efficiency and boost the life of lithium-sulphur batteries.

Lithium-sulphur batteries are one of the most promising areas of energy research today, scientists said.

Researchers from Yale University in the US found that the new material - a dendrimer-graphene oxide composite film - can be applied to any sulphur cathode. A cathode is the positive terminal on a battery.

Sulphur cathodes coated with the material can be stably discharged and recharged for more than 1,000 cycles, enhancing the battery's efficiency and number of cycles, researchers said.

Researchers combined the distinct properties of two material components.

They merged the mechanical strength of graphene oxide with the ability of a dendrimer molecule to confine lithium polysulfides.

The result was a gel-like slurry that can be readily coated as a 100-nanometre-thin film onto sulphur electrodes.

"Our approach is general in that it can be integrated with virtually any kind of sulphur electrode to increase cycling stability," said Hailiang Wang, assistant professor of chemistry at Yale University.

"The developed film is so thin and light it will not affect the overall size or weight of the battery, and thus it will function without compromising the energy and power density of the device," Wang added.

The study was published in the journal Proceedings of the National Academy of Sciences.