Inlyte Energy moves toward U.S. manufacturing of iron-sodium batteries

Iron-sodium batteries were “hiding in plain sight,” according to Inlyte Energy, although the technology was developed in the 1980s alongside chemistries like sodium-nickel chloride, iron-sodium batteries remained rarely used.  

The tide is shifting, as the long-duration energy storage company announced a strategic partnership with Horien Salt Battery Solutions (formerly FZSoNick) that aims to scale up Inlyte’s presence in the United States. Horien is a Swiss company that developed a salt battery, and it will bring its manufacturing expertise to the alliance, while Inlyte’s advanced cell design will be used in the low-cost, durable modules. 

“Our batteries use abundant, low-cost metals,” said Ben Kaun, Inlyte’s chief commercial officer. He noted that the California company has re-engineered a proven sodium-based technology that’s known and valued for its safety and long life. And module size is flexible.  

“Iron-sodium batteries have this interesting feature where if you want to make a longer-duration battery, you just need to add more iron and salt. Once you’ve built one that cycles to a five-to-ten hour discharge rate, you can add more iron and salt to get 24 hours of backup power.”  

The announcement of the partnership with Horien to scale up production for its first U.S.-based factory signals that Inlyte is ready to move beyond the pilot phase and into the global marketplace.  

Founded in 2021 by then Ph.D student and current CEO Antonio Baclig, Inlyte acquired UK-based Beta Research Ltd., the research group that first developed sodium metal halide batteries more than 40 years ago. Many of the core scientists are now working with the team, and Beta Research operates Inlyte’s fully-functional pilot production line.  

The company raised $8 million in seed funding in 2023, which helped accelerate its work toward commercialization.

Inlyte’s batteries offer round-trip efficiencies greater than 80% as well as an extended cycle life. Kaun said that their battery efficiency is unique among non-lithium chemistries. In some cases, he added, “We are even outperforming lithium on certain metrics.” 

The company’s first U.S. factory will be developed through the strategic partnership with Horien, which boasts over 25 years of experience in sodium metal chloride battery manufacturing. Though site selection is still occurring, the companies plan to start commercial production by 2027. At opening, the factory is slated to produce 2 GWh per year, Inlyte told pv magazine USA.  

“Once we hit the gigafactory level,” said Kaun, “We anticipate that our technology will be able to compete with lithium-ion for use cases like load shifting and will offer a cost-effective, safer solution for grid-scale projects.” 

Even so, the company faces a long road ahead. Kaun noted that while their battery production remains at a low volume, it can be harder to justify the price at the current volume. He’s optimistic, however, about Inlyte’s future and scaling up production.  

“I’d always assumed [iron-sodium batteries] were too expensive,” Kaun said. “It’s not necessarily a logical deduction that you could make the cheapest grid battery from a battery known as one of the most expensive batteries, but you have to start from the bottom and work your way up so you can understand where the unit economics go.” 

The target market for Inlyte’s batteries is the diurnal energy storage market, with a storage duration of four to 10 hours. The company says this makes them appropriate for grid storage and other industrial applications.

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