Germany-based tech startup Theion is developing sulphur batteries, designed to replace critical raw materials such as cobalt and nickel.
The company, which was founded in 2020, aims to reduce costs and weight to a third of the current battery technology. It has focused on the monoclinic gamma crystal structure of sulphur, which could be used for high energy density, low weight and a lower environmental footprint.
The goal is for lithium-sulphur batteries with energy densities of up to 1000Wh/kg and 1200Wh/l.
Theion is using sulphur because it is a globally available industrial by-product, and also to reduce dependency on geopolitically sensitive supply chains. The sulphur is processed using patented methods to avoid polysulphide migration to the alkali metal electrode.
Sulphur is used on the cathode with lithium metal on the anode for a higher energy-to-weight ratio compared to compared to conventional lithium-ion batteries.
The approach of the sulphur crystal battery has been confirmed by the company’s functional prototypes in the form of coin cells. The next development step is the completion of a more powerful pouch cell.
Marek Slavik, co-founder, Theion, said, “Many companies are researching sulfur as a basis for battery technology. At theion, we work with the monoclinic gamma crystal structure. Drexel University in the USA has shown in studies that this specific crystal structure is particularly suitable for batteries. It makes efficient use of the sulfur storage capacity by optimising the active material surface and contributes to increased cycle stability. The Drexel research team was able to demonstrate over 4,000 complete charge and discharge cycles without significant capacity loss – an important step towards viable lithium-sulphur batteries.”
Image: Sulphur in its monoclinic gamma crystal structure. Credit: Theion.
