Lithium-sulphur batteries, viewed as a promising alternative to today’s lithium-ion technology, could deliver lighter, more cost-efficient and sustainable energy storage. But researchers say the technology still faces technical hurdles before it can be widely adopted.
A team at the Helmholtz Centre Berlin (HZB) has used neutron tomography to study how electrolytes behave inside lithium-sulphur (Li-S) cells. These batteries, which could exceed 700 Wh/kg in energy density compared with about 250 Wh/kg for current lithium-ion cells, use sulphur as a plentiful and less critical material than cobalt or nickel. Such performance gains could benefit electric vehicles, drones, aviation and space applications.
In the study, scientists observed that limited amounts of liquid electrolyte in Li-S cells can leave certain areas “dry,” disrupting chemical processes and shortening battery life. “It is crucial how the electrolyte wets the electrodes, penetrates their pores and distributes itself in the Li-S cells,” said HZB chemist Prof. Dr. Yan Lu, who led the research. Neutron tomography, similar to a CT scan but using neutrons instead of X-rays, enabled the team to observe the electrolyte’s movement without dismantling the battery.
Tests on specially built Li-S pouch cells showed that electrolyte distribution improved significantly when the battery was in use, enabling more active sulphur utilization and increased capacity. The researchers also discovered a periodic wetting pattern linked to sulphur compound formation and dissolution, a behaviour distinct from lithium-ion batteries.
The findings could help engineers design lighter, longer-lasting Li-S batteries, potentially boosting electric vehicle range and advancing aerospace applications. The work was supported by the German Federal Ministry of Education and Research and the European Union.
Industry interest in Li-S technology is growing. The EU-backed TALISSMAN project has begun work on developing Li-S batteries for electric vehicles, while U.S. developer Lyten, currently in the process of acquiring Sweden’s Northvolt, operates a pilot production line in California and has already delivered sample cells to automakers including Stellantis.