U.S. startup Factorial Energy is seeking to develop solid-state batteries through an alliance comprising companies specializing in different components of the supply chain, viewing cooperation among anode, cathode, electrolyte, and manufacturing-equipment developers as necessary to reach a commercially producible product.
In its latest move, Factorial signed a joint development agreement with Japan’s Mitsui Kinzoku to use its solid electrolytes in Factorial batteries. Siyu Huang, the company’s chief executive officer, said that access to this material is important for improving the performance of the Solstice battery and achieving greater thermal stability at high temperatures.
What Is Factorial Trying to Change?
Traditional lithium-ion batteries use a flammable liquid electrolyte to transport ions. Fully solid-state batteries replace this liquid with a solid material, which could limit fire risks, increase energy density, and support fast charging. However, these promises continue to face technical challenges, while conventional batteries continue to improve driving range, charging speed, and cost.
Factorial is working with South Korea’s Posco Future M on anodes and cathodes, and is exploring expanding the technology with SK On. It has also signed joint development agreements with Volkswagen Group subsidiary PowerCo and Hyundai Motor Group, and signed a memorandum of understanding with South Korea’s Phil Energy regarding advanced manufacturing tools.
Two Products at Different Levels of Readiness
Factorial offers the semi-solid FEST battery, which uses a gel-like electrolyte, and the fully solid-state Solstice battery. Both products use nickel-manganese-cobalt (NMC) cells with a lithium-metal anode-free cell design.
FEST’s targeted energy density reaches 375 watt-hours per kilogram, and prototypes of it have been installed in Mercedes-Benz EQS and electric Dodge Charger Daytona vehicles. Solstice, meanwhile, targets up to 450 watt-hours per kilogram. However, neither product has entered production vehicles so far.
Factorial says FEST technology is ready for commercialization and that it has received orders from customers, while Karma Automotive is expected to become the first company to launch a production vehicle equipped with its semi-solid battery in 2028. Factorial has also received its first commercial order for a battery intended for a drone.
Why Does This News Matter?
The most important development is not the announcement of a new material itself, but the adoption of a collaborative model that distributes battery-development challenges among several companies. This model could help Factorial reach production and benefit from its partners’ expertise in materials and manufacturing, but it does not prove that solid-state batteries are ready for widespread deployment.
The company also continues to face competition from QuantumScape, Solid Power, and Pure Lithium, as well as Toyota, ProLogium, and major Chinese battery companies such as CATL and BYD. The key questions therefore remain tied to the alliance’s ability to scale manufacturing, turn announced performance into a reliable product, and meet the announced commercial timelines. The comparison between Factorial’s collaborative approach and more vertically integrated models also remains open.