​In theory, lithium-sulfur batteries offer twice the energy-storage mass as lithium-ion batteries, making lithium-sulfur an attractive potential alternative for uses like electric vehicle range extenders. However, until recently, the technology had only been proven on button batteries in the lab. Scaling up has turned out to be complicated due to the solubility of the sulfur and the implementation of the lithium in metal form.

Liten researchers modified the battery cell design and electrode implementation processes to partially resolve these problems. “When you increase the battery’s size, the amount of electrolyte decreases proportionally, and so does the efficiency of the reactions,” said a Liten researcher. “To counter the problem, we changed the battery design to make the sulfur more available for the oxidoreduction reactions.”

The initial test results were as good as—if not better than—what had been obtained on button batteries in the lab: 56% of the sulfur’s theoretical capacity is recovered with the new design. “But there is still a lot of room for improvement. We hope to double the battery’s performance just by changing the format.”