At equivalent weight, lithium-sulfur (Li-S) batteries last three times longer between charges than the lithium-ion batteries powering most of our everyday items. This makes Li-S batteries ideal for electric vehicles, aircraft, or anywhere else a large amount of on-board energy is needed and where space is tight.

But Li-S batteries have a limited lifetime. “During discharge, the sulfur from the positive electrode dissolves in the liquid electrolyte used to transfer ions from one electrode to another. With each cycle, the negative lithium electrode corrodes and an insulating layer forms on the positive sulfur electrode, increasing its electrical resistance and greatly reducing the amount of energy supplied.” To overcome this problem, Liten researchers decided to take advantage of lithium-sulfur’s solubility, placing it directly in the electrolyte. The result is a liquid positive electrode, or “catholyte”. They also increased the active surface of the positive electrode’s current collector using carbon nanotube mats placed on a strip of aluminum.

These two tricks combined increased the amount of sulfur in the battery to achieve higher specific energy while maintaining current cycling lifetimes at higher discharge rates. The Li-ion battery now has a worthy successor.