Polyaniline-grafted hydrolysed polyethylene as a dual functional interlayer/separator for high-performance Li–S@C core–shell batteries

Battery separator with a sulfur lining

30 April 2020

A two-layer separator material that tightly limits the chemical species that can pass through it could be the key to long-lasting lithium–sulfur rechargeable batteries.

Lithium–sulfur batteries have an energy-storage density five times greater than today’s lithium-ion batteries, but their capacity fades rapidly. One cause of this capacity loss is the formation of soluble lithium polysulfide (LP) intermediates at the cathode during discharge. These LPs migrate across the battery, passing freely through the separator layer, and contaminate the anode.

LP migration can be suppressed by adding an additional polymer layer to the separator material, researchers at the Vidyasirimedhi Institute of Science and Technology have shown.

The team added a polyaniline coating to the separator, which features nitrogen-based imine functional groups that selectively interact with the LPs and stop them from passing through, reducing capacity fade of this promising battery technology.

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References

1. Chemical Communications 55, 14263–14266 (2019). doi: 10.1039/c9cc07725a