Factorial FEST and Solstice Solid-State Battery Platforms

Factorial is a US solid-state battery developer headquartered in Billerica, Massachusetts, founded in 2019 by Siyu Huang, Alex Yu and Hector Abruna as a spin-out of a company created at Cornell University in 2013. It has a Korea operation for sales, supply chain and recruiting. It addresses the energy density and safety limits of conventional lithium-ion cells for electric vehicles and other weight-sensitive uses.

Its FEST platform combines an ultrathin lithium-metal anode, a quasi-solid polymer electrolyte and a high-capacity cathode, and is designed to be about 80% drop-in compatible with existing lithium-ion lines. Solstice is an all-solid-state platform with a sulfide electrolyte, dry-coated electrodes and operation above 90 C. The Gammatron AI software provides digital twins for electrolyte development, cell health prediction and fast-charge optimisation. Automakers such as Mercedes-Benz, Stellantis and Hyundai Motor Group test its cells.

• FEST quasi-solid platform: lithium-metal anode with a quasi-solid polymer electrolyte.
• Solstice all-solid-state: sulfide solid electrolyte with zero liquid content.
• Dry electrode process: dry coating that cuts energy use and operating cost.
• Line compatibility: FEST is about 80% drop-in on existing lithium-ion equipment.
• Gammatron AI: battery digital twins for electrolyte design, health prediction and BMS work.
• Automotive validation: 100+ Ah cells tested by global automakers.

Vietnamese EV makers and battery plants could join joint development programmes to evaluate FEST cells for longer-range vehicles using existing lithium-ion equipment. Drone and aviation developers could test lithium-metal cells for weight-sensitive platforms, and R&D teams could use Gammatron for cell modelling.

FEST is designed as an 80% drop-in technology, so cell makers can adopt it without heavy investment or retooling. Factorial shipped 106 Ah automotive B-sample cells to multiple global OEMs in 2024, and the company cites a drive of more than 1,200 km on a single charge with solid-state cells. Dry coating in Solstice lowers operating cost and energy use, and the Gammatron platform reduces the number of physical prototypes needed.

Automakers and Asian cell makers such as SK On and materials suppliers like Mitsui Kinzoku are moving solid-state batteries toward pilot and mass production to gain range and safety. Southeast Asian EV programmes and battery plants will follow these supply chains, making licensable, line-compatible solid-state technology relevant for regional manufacturers.

Factorial was founded in 2019 as a spin-out of a 2013 Cornell University company and is headquartered in Billerica, Massachusetts, with a Korea team for sales and supply chain. Mercedes-Benz has invested, and partners include Stellantis, Hyundai, Kia, Mitsui Kinzoku and SK On. It unveiled a 100+ Ah cell at CES 2023 and shipped 106 Ah B-samples in 2024. It is ranked on the Top 100 Private Deep Tech Companies list.