• 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.

"I am very pleased that we have been able to enter into this joint development agreement with Factorial," said Dr. Kiyotaka Yasuda, Senior Executive Officer, General Manager, Business Creation Division of Mitsui Kinzoku Company, Limited. "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.

“Battery innovation can't be done by one single company," said Siyu Huang, CEO of Factorial. "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.

About Factorial Energy
Factorial Energy (Nasdaq: FAC) is a leading American solid-state battery innovator backed by IQT – the not-for-profit strategic investor for the U.S. national security community and America’s allies – and Mercedes-Benz, Stellantis, Hyundai, and Kia. Through its proprietary FEST® and Solstice™ platforms, engineered for scalable manufacturing, Factorial delivers industry-leading performance across aerospace, energy storage and mobility applications. In 2026, Factorial's initial drone flight test achieved 30% longer range, and the company secured its first commercial orders in both aerospace and passenger vehicle applications. In automotive, Mercedes-Benz’ real-world road testing in a lightly modified test vehicle achieved over 1,200 km of range on a single charge, with the technology also successfully integrated into a fully built Dodge Charger Daytona demonstration vehicle in partnership with Stellantis.. For more information, visitwww.factorialenergy.com.

About Mitsui Kinzoku
Mitsui Kinzoku is a Japan-based global materials company and a leading manufacturer of non-ferrous metals and advanced materials, providing innovative solutions primarily for the automotive and electronics industries. Leveraging its core strengths in non-ferrous metals, functional materials, and recycling technologies, the company develops and manufactures a wide range of high-performance products, including automotive components, semiconductor materials, battery materials, and engineered materials. With a strong focus on innovation, environmental responsibility, and resource circulation, Mitsui Kinzoku collaborates with partners around the world to create new value and will continue to contribute to the realization of a sustainable society.

Forward-Looking Statements
Certain statements in this communication may be considered forward-looking statements. Forward-looking statements generally relate to future events or Factorial’s future financial or operating performance, including expectations regarding manufacturing capabilities, commercialization plans, business strategy, customer programs, partnerships, supply-chain development and production readiness. In some cases, forward-looking statements can be identified by terms such as “may,” “should,” “expect,” “intend,” “will,” “estimate,” “anticipate,” “believe,” “predict,” “project,” “target,” “plan,” “potentially” or similar terminology. These statements are subject to risks, uncertainties and other factors that could cause actual results to differ materially from those expressed or implied. Factorial undertakes no obligation to update forward-looking statements except as required by law.

Factorial has used, and intends to continue to use, its Investor Relations website (https://ir.factorialenergy.com), as a means of disclosing material non-public information and for complying with its disclosure obligations under Regulation FD. Information on or that can be accessed through Factorial’s Investor Relations website, or that is contained in any website to which a hyperlink is provided herein is not part of this press release, and the inclusion of Factorial’s Investor Relations website address, and any hyperlinks are only inactive textual references.

Factorial IR Contact:
IR@factorialenergy.com

Factorial Media Contact:
Factorial@antennagroup.com

A photo accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/7c718db9-61c2-4ef9-8111-13e68368dabb

Factorial Energy and Mitsui Kinzoku Partner to Advance All-Solid-State Battery Industrialization

Alex Yu, co-founder and CTO of Factorial Energy (left), and Dr. Kiyotaka Yasuda, Senior Executive Officer and General Manager, Business Creation Division at Mitsui Kinzoku Company, Limited (right), mark the companies’ joint development agreement to advance the industrialization of Factorial’s Solstice™ all-solid-state battery platform.

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