Growing interest from consumers and industry in sodium ion batteries is being driven by rising energy demands and extreme weather, as stakeholders seek safer and more cost-effective energy storage solutions. Although this technology is gaining ground in the US and Europe, a majority of battery cell manufacturing still takes place in China, raising ongoing concerns about cost, performance, and safety as scaling accelerates.
Homeowners Across Europe Turn to Batteries Amid Heatwaves
Intense heatwaves this summer pushed many European homeowners to adopt advanced battery technologies to mitigate high air conditioning expenses. Unigrid, a US-based battery manufacturer, experienced a surge in sales from markets including the Netherlands, Germany, France, and Spain. CEO Darren Tan stated that users deploy Unigrid’s nine kilowatt hour home batteries to store cheaper electricity during off-peak hours, allowing them to power air conditioners without depending on peak-priced grid electricity during the hottest times. Unigrid shipped 100 units across Europe so far, with plans to reach 1,000 units by the close of the year.
Instead of lithium ion, Unigrid utilizes sodium ion cells in their batteries. According to the International Energy Agency, sodium ion batteries are drawing attention due to their lower production costs, improved fire resistance, and impressive operational range that could remain effective down to minus 40°C.
Performance, Chemistry, and Safety Remain Under Scrutiny
Sodium ion battery technology still sparks debate regarding its safest and most efficient form. The field has witnessed several failed attempts by US startups, and China continues to dominate global sodium ion battery production, posing both supply issues and competitive pressure for American companies.
For battery cells, Unigrid is currently dependent on Chinese suppliers but is investigating future partnerships with US producers. The cells feature a cathode containing chromium-3, an element with potential risks. As Prof Dame Clare Grey of the University of Cambridge points out, chromium-3 can transform into chromium-6 under certain conditions—a compound identified as a carcinogen. In response, Unigrid’s CEO states that both European certification and US safety assessments have yielded no significant risks: “We’ve tried very hard to try and produce it, we’ve overcharged it… We were unsuccessful in generating chromium-6,” notes Tan.
Supporting these findings, University of Warwick’s Ivana Hasa affirms that precise voltage control can prevent the formation of chromium-6, and she considers Unigrid’s safety data to be “very promising.”
Efforts to Build US Supply Chains and Industry Leadership
The reliance on China for lithium ion battery materials and manufacturing is prompting US businesses to seek sodium ion battery production that leverages American raw materials. The long-term objective for Unigrid is to develop products using exclusively domestic supply chains, thereby reducing overseas dependency.
Innovation in the US is not limited to Unigrid. Emerald Battery Labs out of Seattle focuses on sodium ion auxiliary batteries for automotive use, beginning with China-sourced components but aspiring to create proprietary US-manufactured designs. Meanwhile, Peak Energy, with operations in Colorado and California, has joined forces with General Motors to establish an American sodium ion supply chain, aiming to start up battery production at a Michigan facility by the end of 2028.
From a pricing perspective, December figures showed lithium iron phosphate (LFP) battery packs selling at $81 per kWh as reported by BloombergNEF, whereas Unigrid’s sodium ion technology stood at approximately $100 per kWh. Optimistic industry forecasts suggest that sodium ion prices could eventually dip to $30 per kWh, but sources such as Nature project that this will take several more years.
Sodium ion batteries generally lag behind lithium ion in terms of energy density, rendering them heavier and bulkier. While there have been recent improvements, these batteries are unlikely to be used in compact gadgets like smartphones in the near term. Their strengths are instead found in large-scale storage scenarios and for grid-level applications.
Growing Data Centers Push Demand for Battery Alternatives
The escalating electricity consumption from US data centers, coupled with related environmental concerns, has created an opening for battery innovators. Drew Buckley, CEO of ESS Tech in Oregon, remarks that sodium ion batteries could offer a cheaper alternative while cutting cooling needs for distributing renewables to data centers. ESS Tech and Alsym are on track to provide “hundreds” of megawatt hours of US-produced sodium ion batteries by 2027.
Scaling mass production of sodium ion cells within the US remains a major challenge, according to Hasa at the University of Warwick. She also highlights that while sodium ion batteries are marketed as safer than lithium ion, a fire risk still exists. Overcoming technical and supply hurdles may provide crucial benefits, such as reducing wasted renewable energy and cutting overall energy costs.
Rising demand from both the urgent climate situation and the growth of new technology sectors ensures that the coming years will prove critical for the wider adoption and evolution of sodium ion battery technology in global consumer and industrial applications.