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Unigrid’s Sodium-Ion Battery Aims for U.S. Production Amid Safety and Cost Debates
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Unigrid’s Sodium-Ion Battery Pushes U.S. Manufacturing
Unigrid’s grid-scale battery currently incorporates sodium-ion cells sourced from China, but the company says it can “switch back and forth” to U.S.-made cells once domestic supply chains mature. Founder Tan argues that concerns about the toxicity of the battery’s materials are “overblown,” noting that the system has passed European certification and is undergoing U.S. safety evaluations. Third-party testing, according to Tan, has not succeeded in generating chromium-6, even after deliberate over-charging attempts.
Technical Debate Over Chromium-Based Cathodes
On May 3, Prof Dame Clare Grey of the University of Cambridge (co-founder of Nyobolt) warned that under certain high-state-of-charge conditions, chromium-3 in the cathode can convert to chromium-6, a known carcinogen. Ivana Hasa of the University of Warwick, who has no ties to Unigrid, concurs that the conversion is possible but can be mitigated through precise voltage control. Both experts stress that safety testing of Unigrid’s chemistry has yielded promising results, while Tan maintains that the risk has not materialized in practice.
Cost Landscape and Market Outlook
Last December, lithium-ion LFP batteries traded at $81 per kilowatt-hour. Unigrid’s sodium-ion offering is priced at roughly $100 per kilowatt-hour. Some manufacturers interviewed by the BBC suggest that sodium-ion costs could eventually fall to $30 per kilowatt-hour, but analysts caution that such reductions are likely many years away. The lower energy density of sodium-ion cells means they must be larger and heavier than comparable lithium-ion units, limiting their suitability for compact devices but keeping them attractive for large-scale storage.
Industry Context and Competitive Pressures
China presently leads global sodium-ion battery manufacturing, giving U.S. firms a competitive hurdle. The prospect of a fully U.S.-sourced battery is presented as a strategic advantage over lithium-ion supply chains, which are also dominated by China for raw materials and production. Unigrid’s flexible sourcing strategy reflects the broader industry effort to balance cost, safety, and supply-chain independence.
Next Steps and Certification Status
Unigrid is completing U.S. safety assessments while exploring domestic cell suppliers. The company’s ability to maintain performance without chromium-6 formation will be a key factor in securing broader market acceptance and achieving the projected cost reductions cited by industry observers.