The Series A funding round was led by technology holding company Team Global, the Geschwister Oetker Beteiligungen group and German renewables firm Enpal.
Theion says its batteries have three times the energy density of conventional lithium-ion batteries, but cost only a third as much and emit a third of the carbon dioxide.
CEO Ulrich Ehmes told Reuters that theion's batteries could be used for electric vehicles, flying taxis or energy storage and that in theory those cells could be in electric vehicles on the road before the end of the decade.
Ehmes said that theion has successfully developed small coin cell batteries and the funding will be used to develop the larger pouch cells needed to power EVs or airplanes.
"We are under observation of car companies, stationary storage companies, companies in the electric aerospace sector," he said. "Everyone is now waiting for our first pouch cells because with the coin cell you cannot fly an aircraft."
The company is among a number of startups in the United States and Europe trying to make a breakthrough with sulfur.
The main challenges facing sulfur battery cells are historically they have tended to corrode quickly and also tend to "breathe" - where they expand and destroy battery packs.
Ehmes said theion has overcome these challenges by using crystalline sulfur to avoid corrosion and pre-expanding the battery's cathode.
