Factorial and Mitsui Kinzoku Partner to Scale All-Solid-State Battery Manufacturing

Mitsui Kinzoku Partners with Factorial to Scale All-Solid-State Battery Manufacturing

• Strategic partnership expected to accelerate global scale up of Factorial’s all-solid-state Solstice™ platform
• Mitsui Kinzoku, one of the few companies in the world holding foundational solid-state electrolyte technology, signs Joint Development Agreement to help power the scale up
• The partnership positions Solstice™ at the center of an industry wide push toward commercializing all solid-state batteries.

BOSTON, Sept. 17, 2026 (GLOBE NEWSWIRE) — Factorial Energy Inc. (“Factorial”) (Nasdaq: FAC), a global leader in solid-state battery technology, today announced a strategic partnership with Mitsui Kinzoku Company, Limited to support the industrialization of its Solstice™ all-solid-state battery platform.

Mitsui Kinzoku is a leading producer of sulfide-based solid electrolytes for all-solid-state batteries, one of few companies worldwide with foundational technology in this space, and already the global leader in ultra-thin copper foil, with an estimated 90% share of the semiconductor market for that foil. That materials science expertise underpins its A-SOLiD™ sulfide solid electrolyte, unveiled in 2016 and advancing toward mass production at a dedicated plant in Saitama, Japan.

Dr. Kiyotaka Yasuda, Senior Executive Officer, General Manager, Business Creation Division of Mitsui Kinzoku Company, Limited, said:

I am very pleased that we have been able to enter into this joint development agreement with Factorial,

“Batteries are a key technology for realizing an electrified society, but significant technical challenges still remain. That is precisely why we believe it is necessary to go beyond the extension of existing technologies and take on the challenge of creating new value. By leveraging Mitsui Kinzoku’s long-established expertise in materials and manufacturing technologies and combining it with Factorial’s advanced technological capabilities, we aim to accelerate the realization of next-generation batteries.”

Factorial remains the fabless innovator across the platform, leading cell design, process development, supply chain qualification, line integration, and manufacturing validation.

Siyu Huang, CEO of Factorial, said:

Battery innovation can’t be done by one single company,

“It’s driven by the entire supply chain and, increasingly, by an entire industry coalition. Mitsui Kinzoku’s foundational electrolyte technology brings critical materials expertise to our work to move Solstice™ toward commercial deployment. We’re not just building a battery. We’re building the connective thread that helps the whole industry move forward together.”

As robotics, aerospace systems, and AI-enabled infrastructure ask more of the physical world, energy is fast becoming the defining constraint on what’s possible. Factorial calls this the emergence of the energy layer – the battery infrastructure needed to power the next era of mobility, aerospace and physical intelligence. Built for that layer, Solstice™, Factorial’s sulfide-based all-solid-state battery platform, delivers high energy density and improved thermal stability, with proprietary dry-cathode processing enabling more cost-effective manufacturing.

This collaboration builds on Factorial’s recent momentum, including strategic investments from IQT and POSCO Future M; its first commercial orders for passenger vehicles in January and for aerospace in July; expanded automotive and industrialization partnership programs; and its June 2026 Nasdaq listing under the ticker symbol FAC.

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Mitsui Kinzoku Partners with Factorial to Scale All-Solid-State Battery Manufacturing, source