Donut-Shaped Electrodes Make Li-S Batteries More Durable

Researchers in South Korea have developed a donut-shaped lithium sulfide cathode that boosts the lifecycle of lithium sulfur batteries.

AsianScientist (Oct. 2, 2018) – A research team at the Korea Advanced Institute of Science and Technology in South Korea has developed a lithium-sulfur (Li-S) battery with a doughnut-shaped structure that remains functional over 600 charge-discharge cycles. Their findings are published in Advanced Science.

Despite their usefulness in consumer electronics products, lithium ion batteries have charge densities that are too low for practical use in electric vehicles, only allowing a very short travel distance per charge. Hence, researchers are looking into Li-S batteries which potentially have a much higher energy density. However, the durability of Li-S batteries is low due to the properties of the lithium metal cathode.

To tackle this issue, researchers led by Professor Kim Hee-Tak at KAIST used lithium sulfide (Li2S) cathodes combined with graphite anodes to enhance the energy density and lifecycles of the batteries. The scientists also tweaked the electrode architecture and electrolyte design of the batteries, settling on a donut-shaped lithium sulfide cathode and a highly concentrated electrolyte solution.

The donut-shaped lithium sulfide cathode showed outstanding charge and discharge reversibility due to the improved transfer of lithium ions. In addition, the use of a highly concentrated salt electrolyte resulted in the formation of a stable film on the surface of the graphite electrode, which prolonged its durability.

Using their technology, the team achieved 30 percent higher energy density than that of conventional lithium ion batteries and a battery lifecycle of more than 600 cycles. The researchers noted that their donut-shaped lithium sulfide-based electrode can be manufactured using low-cost raw materials and a single heat treatment process. The electrode can also be used in existing lithium ion batteries.

“We have demonstrated that the application of low-cost sulfur compounds to lithium ion batteries can improve both energy density and lifecycle of those batteries simultaneously,” said Kim.

The article can be found at: Ye et al. (2018) An Ultrahigh Capacity Graphite/Li2S Battery with Holey‐Li2S Nanoarchitectures.


Source: Korea Advanced Institute of Science and Technology; Photo: Shutterstock.
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