
Massachusetts-based solid-state battery technology company Factorial Energy announced the introduction of Solstice, an all-solid-state battery that can revolutionize the safety, performance, and sustainability of the next generation of electric vehicles.
Solstice is set to achieve a breakthrough energy density of up to 450Wh/kg and incorporates a novel dry cathode design for more efficient and sustainable production. Solstice compliments Factorial’s industry-leading FEST (Factorial Electrolyte System Technology) for automotive and other electric mobility applications while expanding Factorial’s total addressable market to include consumer electronics.
Solstice was developed in collaboration with Mercedes-Benz as part of their ongoing partnership, demonstrating a shared commitment to continuous innovation.
Solstice enables industry-leading performance and safety for electric mobility and Factorial expects the technology to be introduced by OEMs before the end of the decade. Solstice’s high energy density can extend EV range up to 80% while significantly reducing vehicle weight and increasing vehicle efficiency.
Its sulfide-based all-solid-state electrolyte system addresses safety concerns associated with more flammable and volatile liquid electrolyte designs, targeting a EUCAR safety rating of 2 and maintaining stability at operating temperatures over 90°C. This also has the potential to reduce the cooling system requirements within the battery pack to lower overall vehicle cost.
“Solstice embodies our team’s technology leadership and the potential of solid-state batteries to address the most significant hurdles for electric vehicle adoption,” said Siyu Huang, CEO and Co-Founder of Factorial. “Solstice not only will enhance the range and performance of electric vehicles but also aligns with our vision for a more sustainable future. We’re grateful to have Mercedes-Benz’s continued support, which underscores our ability to meet the needs of global automakers now and in the future.”
Solstice is poised to revolutionize battery manufacturing by significantly enhancing sustainability. Through a novel dry coating process, Solstice eliminates the need for hazardous solvents and energy-intensive steps commonly used in traditional cathode production. The technology also bypasses the formation process, the most energy-consuming stage of lithium-ion battery manufacturing. By combining these innovations, Solstice reduces operating costs, energy consumption, and environmental impact, paving the way for a more sustainable future for battery production.
“The Solstice solid-state battery technology represents another landmark milestone in our partnership with Factorial, which is a cornerstone of Mercedes-Benz’s strategy and commitment to leading the charge in battery development,” said Markus Schäfer, Chief Technology Officer and Member of the Board of Management at Mercedes-Benz Group AG. “Solstice™ offers further improvements in energy density and safety features that will help us develop electric vehicles that set new standards in range, cost, and performance.”
This announcement follows Factorial’s delivery of B-samples of its solid-state battery cells utilizing its FEST platform to Mercedes-Benz, an instrumental step in the development and deployment of Factorial’s solid-state batteries utilizing FEST, paving the way for Solstice and the next generation of EVs. Mercedes-Benz entered into a joint development agreement with Factorial in 2021 and led a $200MM investment round for Factorial in 2022.





