Solid-state battery maker Factorial secures another big partnership — SkimNews
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- Factorial Energy announced a partnership with Mitsui Kinzoku, one of the few producers of sulfide-based solid electrolytes, to combine Factorial's Solstice all-solid-state platform with Mitsui's A-SOLiD argyrodite electrolyte technology
- Mitsui Kinzoku will mass-produce the solid electrolyte at a dedicated plant in Saitama, Japan; the company also holds roughly 90% of the semiconductor market for ultra-thin copper foil
- Factorial's Solstice platform delivers up to 450 Wh/kg energy density — about 80% higher than traditional lithium-ion batteries — and remains stable at temperatures up to 194°F (90°C)
- Factorial has existing EV partnerships with Mercedes-Benz, Stellantis, and Hyundai, and recently signed an MOU with SK On to bring its cell technology to SK On's global manufacturing network
- Factorial received its first commercial order for passenger vehicles in January and its first aerospace order in July; CEO Siyu Huang told The New York Times the batteries could appear in EVs as early as 2027, likely starting with high-performance or luxury models
- Mercedes-Benz demonstrated the technology by driving a modified EQS over 745 miles (1,200 km) using Factorial's 106 solid-state cells, while Stellantis reported Factorial's 77Ah FEST cells achieved 375 Wh/kg over more than 600 cycles
Why it matters: The alliance pairs a US solid-state battery startup with the Japanese firm that dominates sulfide electrolyte production, addressing the manufacturing scale bottleneck that has kept solid-state batteries out of mass-market EVs. With Factorial targeting 2027 for first EV deployments and existing automaker partners already road-testing the cells, this partnership materially advances the timeline from lab demo to commercial supply.
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