Insight into the effect of additives widely used in lithium–sulfur batteries

Lithium–sulfur battery performance adds up

27 February 2020

A study that tests some of the assumptions made about an additive used in experimental next-generation batteries could be a step towards commercializing the rechargeable technology.

Lithium–sulfur batteries could have higher capacities than today’s lithium-ion batteries while being cheaper. However, so far, lithium–sulfur batteries degrade too rapidly for commercial uptake. Their lifespan can be extended by adding lithium nitrate (LiNO₃) to the electrolyte, but it is not clear how the additive works.

Researchers from Vidyasirimedhi Institute of Science and Technology have used theoretical reactive molecular dynamics simulations to study the interactions between lithium nitrate and the battery’s lithium anode. They found that additive forms a smooth, dense, protective film over the anode. The film contains Li_xNO_y clusters, which capture the damaging lithium polysulfide compounds that form in the battery and attack the anode and cathode if left unchecked.

This finding could pave the way to improve lithium–sulfur battery lifetime.

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References

1. Chemical Communications 55, 13951–13954 (2019). doi: 10.1039/c9cc06504k