Factorial Energy and Mitsui Kinzoku Company have entered a joint development agreement to support the industrialization of Factorial’s Solstice all-solid-state battery platform.
Mitsui Kinzoku develops sulfide-based solid electrolytes for all-solid-state batteries and is advancing its A-SOLiD sulfide electrolyte toward mass production at a dedicated facility in Saitama, Japan.
Under the agreement, Mitsui Kinzoku will contribute materials and manufacturing expertise to support development and scale-up of the Solstice platform. Factorial will continue to lead cell design, process development, supply-chain qualification, line integration, and manufacturing validation.
Solstice is a sulfide-based all-solid-state battery platform designed to improve energy density and thermal stability. Factorial also uses a dry-cathode manufacturing process intended to simplify production and reduce manufacturing cost.
The collaboration is focused on moving the platform toward commercial-scale production by combining solid-electrolyte development with cell engineering and manufacturing validation.
Factorial has expanded its automotive development work over the past year and reported its first commercial orders for passenger-vehicle applications in January 2026. The company is also working on broader industrialization programs for solid-state batteries.
Filed Under: Batteries, Technology News