Series A · Energy · Berlin, Germany · Founded 2020 · 11–50 employees
theion GmbH is a Berlin-based deep-tech battery startup developing crystal sulfur lithium-sulfur batteries using a patented monoclinic gamma-crystal sulfur structure, targeting up to 3× the energy density of conventional lithium-ion cells at one-third the cost and carbon footprint. The company is Europe's only lithium-sulfur battery manufacturer and targets electric aviation (eVTOLs, satellites), electric vehicles, and stationary energy storage markets. In early 2025, theion raised a US$15.2M Series A round led by Team Global, with participation from Geschwister Oetker Beteiligungen and strategic investor Enpal, validating strong industrial and financial confidence in the technology. The company has expanded to a 1,800 m² facility in Berlin-Adlershof and grown its team to nearly 20 experts from ten countries, while also receiving German federal research funding (BMFTR) for its LiSSy lithium-sulfur project.