More Sodium-Ion Batteries Are Suddenly Emerging

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At the beginning of January, CleanTechnica’s Christopher Arcus took note of the sudden, seemingly out-of-the-blue emergence of sodium-ion batteries on the global energy storage scene, and here we are just midway through the month with more news about sodium-ion batteries. This time it’s the US firm Unigrid, which has set out to go mano-a-mano against the leading battery maker in the field, China’s CATL.

Make That Solid-State Sodium-ion Batteries

Unigrid is a San Diego-based startup founded in 2021, deploying sodium-ion battery research developed at the University of California – San Diego. The launch was assisted by a grant of $150,000 from the California Energy Commission’s CalSEED (California Sustainable Energy Entrepreneur Development) program in 2020.

“UNIGRID LLC is developing a low-cost, safe and sustainable battery for electrical grid storage to solve peak demand, renewable energy storage and power disruption problems during emergencies,” CalSEED explained in a press statement.

“This innovation is a sodium all solid-state battery system that offers low cost, safe and long lasting energy storage to reduce electricity bills and achieve energy self-sustainability,” they added.

That’s quite a mouthful. Solid-state battery technology replaces the traditional, flammable liquid electrolyte with a high-tech ceramic material or some other such substitute. That’s easier said than done, particularly within the emerging field of sodium-ion batteries where reducing the weight of the battery is a significant obstacle. To put that into perspective, innovators in the lithium-ion battery field have been hammering way at the solid-state challenge for years, with some quasi- and semi-solid solutions only just beginning to emerge (see more solid-state battery background here).

So, Did They Do It?

The California Energy Commission must have liked what it saw, because last June they awarded Unigrid a grant of almost $3 million to establish a pilot-scale production line, with an initial target of 250-750 batteries per day for home energy storage. In support of Unigrid’s business model, the pilot facility was tasked with producing cylindrical batteries that can serve as drop-in replacements for other batteries.

“This agreement will fund the design, build-out, and validation of a Low-Rate Initial Production line in San Diego to manufacture advanced Sodium-ion Batteries suitable for residential energy storage with a greater volumetric energy density than is commercially available due to their proprietary electrolyte and anode chemistry,” CEC noted.

As for the use of sodium-ion batteries in electric vehicles, don’t get too excited — yet. Unigrid has stated that transportation applications are in its sights, eventually. However, as of last year the company was focusing on stationary applications, aiming to leverage the benefits of sodium-ion technology to compete against lithium-ion formulas in that space.

Although the main ingredient of sodium-ion batteries — salt — is cheap and abundant, that doesn’t necessarily mean that the finished, marketable battery is any less expensive than an equivalent lithium-ion battery. For home energy storage purposes, though, Unigrid underscores other factors that can tip the balance, including the avoidance of fire risk and environmental hazards, and the elimination of supply chain complications related to global commodities markets and ethical issues.

Unigrid is marketing its stationary batteries as commercial and utility-scale solutions in addition to residential use. The company also offers a product tailored for forklifts, buses, and other industrial vehicles. For the time being, though, the technology is only available to cars and other street vehicles in the form of 12-volt starter batteries.

No, Really, Are Solid-State Sodium-Ion Batteries Really Here?

Unigrid dropped an update on its activities into the Intertubes earlier today. Although the phrase solid-state does not appear in the company’s press statement, the new announcement makes it clear that Unigrid has jockeyed itself into position as the “first battery company outside of China to export sodium-ion at scale.”

That’s a pretty impressive switcheroo from last spring’s pilot-scale enterprise. Unigrid explains that it was able to transition to commercial export scale partly on the strength of UN 38.3 transport certification, which it achieved in 2025 (UN 38.3 is a global safety standard governing the shipment of sodium-ion batteries as well as lithium-metal and lithium-ion formulas).

The company’s subscription-based business model also factored into the effort. “Scaling new battery chemistries is typically constrained by the high costs and long timelines of building dedicated gigafactories, which slows commercialization and limits access to emerging technologies,” Unigrid explains, noting that its “fab-less, foundry-subscription model” leverages manufacturing partnerships instead of relying on the traditional gigafactory model.

“This approach enables rapid global scale-up, with Grade A cells shipped directly from foundries to customers in 40-foot ocean containers,” Unigrid points out.

“Through collaboration with our foundry partners, we’ve proven that advanced battery chemistries can be commercialized without massive capital buildouts,” emphasizes Unigrid CEO and co-founder Darren H. S. Tan.

More Sodium-Ion Batteries Are On The Way, Solid-State Or Not

With all systems go, Unigrid expects to fulfill its off-take agreements this year. Among emerging utility-scale applications, keep an eye out for any interest on the part of hydropower stakeholders. A new report from Pacific Northwest National Laboratory indicates that battery energy storage systems can help hydropower operators save money while earning new revenue.

I’ve reached out to Unigrid for an update on the solid-state angle. In the meantime, new research suggests additional applications, including water desalination.

At the University of Surrey, for example, researchers have been studying a well-known sodium formula called sodium vanadium oxide. It naturally contains water, and the common practice is to apply a heat-based dehydration process under the assumption that water interferes with performance.

The University of Surrey researchers took the opposite tack, and left the water in. “The material showed much stronger performance and stability than expected and could even create exciting new possibilities for how these batteries are used in the future,” explains US researcher and Future Fellow Dr Daniel Commandeur.

“Sodium-ion batteries may be the answer to the future of sustainable energy storage and could be used to make drinking water out of seawater,” US adds.

“The research team also tested how the material behaved in salt water — one of the most challenging environments possible. Results showed it not only continued to function effectively but also removed sodium from the solution while a graphite electrode extracted chloride — a process known as electrochemical desalination,” the school elaborated.

Here in the US, researchers at Brown University have been pursuing another angle, aiming for a precise characterization nature of the “hard carbon” used in sodium-ion battery anodes.

“If you ask 10 different people what the structure of hard carbon is, you’ll get 10 different answers,” notes Brown School of Engineering professor Yue Qi, who co-authored a hard carbon study in the journal EES Batteries. “The ambiguous structures are a major problem for designing the anode materials because of the lack of knowledge of the structure-property relationship.”

Note: The Brown study is published and available here.

Photo: New sodium-ion batteries are pouring into the global market, with US-based Unigrid among those contending for international energy storage off-takers (cropped, courtesy of Unigrid).