A New, Gel-Like Coating Beefs Up The Performance of Lithium-Sulfur Batteries

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A New, Gel-Like Coating Beefs Up The Performance of Lithium-Sulfur Batteries
Left: Ultra-thin material on a glass slide, prepared by casting the gel-like slurry on copper foil and transferring the film. Right: An electrode coated with a layer of the new material. Yale scientists have developed an ultra-thin coating material that has the potential to extend the life and improve the efficiency of lithium-sulfur batteries, one of the most promising areas of energy research today. In a study published online March 20 in the Proceedings of the National Academy of Sciences, researchers describe the new material -a dendrimer-graphene oxide

Lithium-sulfur batteries have the low atomic weight of lithium and moderate weight of sulfur. That means they are relatively light about the density of water. Such kind of batteries is especially noted for its high specific energy. But there is a drawback to it that can’t stably perform charging and discharge cycle. So, to improve the efficiency and life of the lithium-sulfur batteries, scientists from Yale University have developed a gel-like coating i.e., ultra-thin coating material.

Scientists called this material as a dendrimer. It is a graphene oxide composite film that can be applied to any sulfur cathode (positive terminal of the battery).

Hailiang Wang, assistant professor of chemistry at Yale said, “Our approach is general in that it can be integrated with virtually any kind of sulfur electrode to increase cycling stability. The new gel-like coating is so thin and light. It will not affect the overall size or weight of the battery, and thus function without compromising the energy and power density of the device.”

Scientists developed this gel-like coating by combining different properties of two material components. They merged the mechanical strength of graphene oxide with the ability of a dendrimer molecule. This confines the lithium polysulfides. Hence, a gel-like slurry formed that can be coated as a 100-nanometer-thin film onto sulfur electrodes.

Scientists said, “It is essential to have new types of electrodes in a new generation of high-energy-density batteries. As lithium-ion batteries begin to reach their capacity limits, many researchers are looking at lithium-sulfur as a solution. Sulfur is lightweight, abundant and also provide high energy capacity.”

This new gel-like coating allows sulfur cathode to charge and discharge for more than 1,000 cycles. It also improves battery’s efficiency and a number of charge and discharge cycles.