In January 2021, New Scientist published an article spotlighting a promising, and beautifully simple innovation: batteries made using common salt. Sodium-ion batteries were heralded in the article as an economical and sustainable alternative to resource-intensive and deeply unfashionable lithium-ion batteries. Whilst the technology showed initial shortcomings, such as notably lower energy density, sodium-ion “gigafactories” have since cropped up worldwide, from India to North Carolina. So, what’s changed?
Sodium is back
Dr. John Abou-Rjeily has been developing sodium-ion batteries to reduce reliance on lithium at Tiamat Energy in France for years. Sodium, the main element found in everyday table salt, offers an abundant, safer and vastly cheaper alternative to important materials for energy storage, like cobalt, nickel and lithium. Being part of the same alkali metal family, Sodium shares many properties with lithium. These similarities led researchers to conduct the first studies on sodium batteries in the seventies, around the same time similar studies on lithium batteries were taking place. However, while lithium batteries became a huge commercial success due to their better energy storage capabilities, sodium batteries were largely left in the dust.
However, they could be making a comeback. The abundance of negative PR over the last few years surrounding lithium has incentivised further research and investment in sodium batteries. For example, Abou-Rjeily recently led the EU-funded NAIMA project (2019–2023), which brought together institutions from across Europe to advance sodium-ion battery technology. This is just one of many efforts supporting Europe’s goal of building a sustainable battery supply chain as part of its clean energy transition.
The problem with lithium
Lithium-ion batteries dominate today’s energy storage market, powering everything from smartphones to electric vehicles (EVs). They are favoured for their lightweight and high energy storage capacity. However, their production has many downsides.
Lithium extraction is hugely invasive and is known to damage ecosystems, deplete freshwater resources and disrupt local communities. As lithium reserves are concentrated in a few regions, supply chains are often vulnerable to geopolitical tensions, among other issues. Price volatility adds another layer of complexity, with lithium costs fluctuating wildly over recent years. This makes the production of products such as EVs complicated and often prohibitively expensive.
Sodium-ion: A work in progress
Sodium-ion batteries have historically lagged behind lithium-ion batteries in performance. As reported in the 2021 New Scientist article, they store between 5-15 percent less energy per unit of weight. This makes them less suitable for applications like EVs, where weight and range are critical. They have potential especially in areas where weight is not an issue, such as battery storage power plants for wind and solar energy. But, as Rob Armstrong of the University of St Andrews Department of Chemistry unenthusiastically notes; “This material is not fantastically wonderful. It’s a good middle-of-the-road material.”
However, incremental improvements and innovations in sodium-ion technology are starting to shift the narrative.
A niche role in mobility
For one, sodium-ion batteries are finding niche applications. While their lower energy density limits their range, they offer a cost-effective option for urban mobility. Chinese manufacturers are developing several electric vehicles that rely on sodium-ion batteries with ranges under 300 kilometres, making them suitable for city use.
For another, sodium-ion batteries have also been shown to offer other advantages, such as safer transport when uncharged. They also perform better in cold climates. For instance, CATL recently unveiled a sodium-ion battery capable of operating at −40°C (−40°F).
The future of sodium-ion batteries
French firm Tiamat plans to open a gigafactory in Amiens by 2026 to produce sodium-ion batteries that exclude lithium, cobalt and copper, aligning with Europe’s push to reduce dependency on foreign suppliers. Abou-Rjeily highlights that these batteries could be more competitive for applications like power tools and short- to medium-range vehicles.
Around 90 percent of sodium-ion battery factories are currently in China, with major players like CATL and BYD leading the charge. Notable developments are also popping up in India, where Reliance Industries is building a gigafactory to produce sodium-ion batteries using technology from the British startup Faradion. Meanwhile, Natron Energy in the United States plans to significantly scale up its sodium battery production with a new facility in North Carolina.
The International Energy Agency (IEA) predicts sodium-ion batteries will account for 10 percent of all energy storage by 2030. This aligns with global climate goals of increasing energy storage capacity by sixfold by the same year.
While alternatives may never completely replace lithium-ion batteries, especially for high-performance applications, their abundance, safety and suitability for specific markets make them a promising contribution to the energy transition. As Imre Gyuk of the US Department of Energy puts it, “I’m confident sodium-ion batteries will find their market when lithium becomes scarce.”
As global climate goals push for an exponential increase in energy storage and geopolitical tensions continue, sodium-ion technology provides a scalable and sustainable alternative to lithium. The rapid development of gigafactories worldwide in just a few years signals growing confidence in sodium’s potential.
