Factorial Energy Builds Supplier Coalition to Industrialize Solid-State Batteries

Factorial Energy has signed a joint development agreement with Japan’s Mitsui Kinzoku to industrialize its all-solid-state battery platform, as reported by The Next Web (https://thenextweb.com/news/factorial-solid-state-coalition-europe). The partnership is the latest component of a multi-supplier strategy aimed at scaling solid-state vehicle batteries, built on the premise that no individual startup can bring the technology to market alone.

The Nasdaq-listed battery developer, which went public in June, is distributing manufacturing requirements across an international coalition of suppliers. Under this model, Posco Future M oversees anode and cathode materials, South Korea’s Phil Energy provides cell manufacturing tools, and Factorial is exploring high-volume scaling with battery manufacturer SK On. Factorial retains foundational intellectual property for its all-solid electrolytes, while Mitsui Kinzoku manufactures sulfide electrolyte materials at a dedicated facility in Saitama, Japan.

Automakers have also integrated Factorial's technology into validation and testing pipelines. The company holds joint development agreements with Hyundai and Volkswagen’s PowerCo battery unit. Mercedes-Benz serves as both an investor and a test partner, having driven a modified EQS sedan 1,200 kilometers on Factorial cells in September 2025. Stellantis has also supplied a Dodge demonstrator vehicle for cell integration.

Factorial’s product roadmap is divided into two architectures. Its semi-solid FEST cell is rated at up to 375 watt-hours per kilogram and currently powers prototype vehicles from Mercedes and Dodge. Its all-solid Solstice cell targets 450 Wh/kg—roughly double the energy density of conventional lithium-ion cells—with luxury automaker Karma Automotive scheduled as the first commercial recipient in 2028.

Commercializing all-solid-state technology for passenger cars remains a long-term challenge. Last month, the president of LG Energy Solution's North American division noted that solid-state cells will likely appear in smartphones roughly a decade before reaching electric vehicles due to format scaling constraints.

Factorial also faces direct competition from rivals establishing localized production. Taiwan’s ProLogium is already manufacturing 381 Wh/kg all-solid-state cells at an annual run-rate of approximately 6,000 packs in Taiwan. ProLogium broke ground in February on a French gigafactory in Dunkirk, located near the Gravelines nuclear plant. Backed by French state subsidies, that facility is slated to begin at 0.8 gigawatt-hours in 2028 and scale to 12 GWh by 2032.