Sodium-ion batteries (SIB) are emerging as a sustainable and affordable alternative to lithium-ion batteries. After years, researchers and developers now have the opportunity that unlocks batteries for the future of energy storage.
A brief history of sodium-ion batteries
Sodium-ion batteries (SIB) represent a promising alternative to lithium-ion batteries (LIB);
The sodium ion is a good candidate for energy storage for multiple reasons. Sodium is much cheaper and 1000 times more abundant on Earth than lithium, and the available cathodes also use materials that are abundant on Earth, moving away from the supply chain risks of nickel and cobalt in lithium-ion batteries. The chemistry of the sodium ion is based on intercalation just like lithium-ion batteries; sodium ions travel back and forth between the anode and cathode carrying charge and energy. The similarity with sodium-ion batteries from a mechanical, performance, and manufacturing perspective has enabled a simplified transfer of knowledge and accelerated development and commercialization. Current sodium-ion batteries have a lower energy density compared to lithium-ion batteries, making them a valid candidate for large-scale stationary energy storage systems.
Both lithium-ion and sodium-ion cathodes were discovered more or less at the same time. However, research on sodium ions was hampered by the lack of a suitable intercalation anode. Around 2000, the discovery of hard carbon (HC) as an anode material sparked renewed interest in SIBs. The 2010s saw rapid growth, most likely due to the push for alternatives to LIBs, resulting in the development of new cathode materials, full cell assembly, and several startups focused on commercialization. The first cylindrical 18650 SIBs were assembled in 2015 with a Na3V2(PO4)2F3 (NVPF) cathode and an HC anode through the collaboration of several institutions within the French network for electrochemical storage (R2SE). Commercialization efforts produced 1-5 Ah pouch cells from Faradion, the first company to commercialize SIBs; a statement of 10,000 SIBs produced by Tiamat, the startup born from R2SE; and the announcement of a 100 kWh battery installation for energy arbitrage by the Chinese company HiNa. Physics-based modeling can play a unique and important role in the ongoing development of SIBs.
The first physics-based pseudo-two-dimensional (P2D) model for sodium-ion batteries was published in 2022 by Chayambuka et. al. The model uses the generalized framework of the Doyle-Fuller-Newman P2D model for lithium-ion batteries, which predicts the performance and dynamics of intercalation batteries. The modeling work was paired with experiments on a sodium battery with a cathode made of NVPF particles, an HC anode, and a 1 M NaPF6 EC 0.5 : PC0.5 (p/p) electrolyte. The reaction for NVPF is:
Na3VIII2(PO4)2 <--> F3 NaVIV2 (PO4)2F3 + 2Na+ + 2e−
where 2 Na+ are transferred for each unit of NVPF, with a capacity of 128 mAh/g. HC is a non-graphitic carbon with a complex structure: they have graphene-like layers within an amorphous microporous phase. Charge transfer occurs via adsorption on graphene layers and filling of meso- and nano-pores. There are multiple proposed mechanisms for HC, which may depend on the precursor and structural properties, and this remains an active area of research. The specific capacity of HC is about 300 mAh/g, similar to that of graphite in LIBs.
Parameterization of models can be difficult and complex, but remains a key component to ensure accurate battery models. To create a set of experimentally predictive base parameters, the authors of the SIB P2D model used experimental techniques and parameter estimates on GITT and cyclic data on half and full cells, as well as electrolyte measurements and statistical mechanics simulations for transport properties. The scheme for the sodium-ion battery can be found in the figure above, taken directly from their work. A 3-electrode configuration was used with a Na-ion reference electrode to individually measure electrode voltages, and the model output was optimized on that rather than the total battery voltage to minimize error. The relevant parameters and process details can be found in their experimental and modeling papers (ref. 1 and 2).
This work highlights the power of appropriately parameterized physics-based models; model predictions for rates from 0.1C to 1.4C were less than 2% error compared to experimental curves and less than 50 mV absolute error. The authors found that contact resistance becomes important at higher rates for accurate predictions. In addition, high-rate performance was hindered by poor mass transport in both the electrodes and the electrolyte. The results suggest that reducing the particle size in the HC electrode will improve high-rate performance while diffusion within the NVPF particles was found to limit mass transport.
The figure below reproduces the C-rate study by Chayambuka et al. The
The landscape of sodium-ion batteries is evolving rapidly, as leading companies innovate to meet the growing demand for sustainable energy solutions. This development is a response to the increasing need for alternatives to traditional lithium-ion batteries. By 2033, the global sodium-ion battery market is expected to grow from $438 million in 2024 to over $2 billion, growing at a compound annual growth rate of 21.68%. Here are the main sodium-ion battery companies in 2025:
Altris AB
Swedish company Altris AB has introduced a commercial-size sodium-ion battery cell that offers an energy density comparable to lithium-ion LFP batteries. By collaborating with Clarios for low-voltage automotive uses and Polarium for energy storage, Altris AB is paving the way for practical sodium-ion adaptations.
As the sodium-ion battery market evolves, these six companies are leading the charge with groundbreaking innovations and partnerships. Their technologies promise to provide sustainable energy solutions, paving the way for a future less dependent on lithium-ion batteries.
TIAMAT, based in France, develops sodium-ion batteries suitable for mobility and stationary energy storage. Their batteries have attracted attention for their ability to charge in just five minutes and for their high safety standards. TIAMAT recently secured 30 million euros to establish a factory capable of producing 5 GWh of sodium-ion batteries per year in France.
Northvolt is making waves with a sodium-ion battery that exceeds an energy density of 160 Wh/kg. This Swedish company produces batteries without relying on critical metals. Instead, it uses abundant and low-cost materials, making its solutions both economical and sustainable.
Faradion Limited, a British company, specializes in non-aqueous sodium-ion battery technology. These batteries are designed for high-power applications such as electric vehicles and grid storage. Faradion's products stand out for their long lifespan and ability to operate over a wide temperature range.
Small pilot plants and large projects
Currently, mainly pilot plants are in operation and some smaller factories are being started, producing only a few gigawatt hours (GWh) of sodium-ion batteries per year, but the publicly announced capacities by various raw material and battery manufacturers amount to well over 100 GWh by 2030. By 2025, a significantly greater capacity than has been financed so far could be developed if investors are found during 2024. The forecast of a radical conversion of much of the sector to a new technology in just a few years may seem bold, but in the last five years alone, this has happened twice in the battery sector with NMC811 and LFP. Sodium ions hardly require new plant technology, just different starting materials and production parameters.
Significant savings compared to LFP are initially unlikely
Currently, there is no cost-effective battery technology with an energy density between lead-acid and lithium batteries. According to IDTechEx research, the average cell cost for sodium-ion batteries is $87/kWh, taking into account the different chemistries. By the end of the decade, the production cost of sodium-ion battery cells using mainly iron and manganese will likely bottom out at around $40/kWh, which would be about $50/kWh at the pack level. Sodium-ion cells are likely to initially be priced at a premium, but IDTechEx expects a drop in cost/price in the short term through manufacturing efficiencies, scale, and technological development. However, long-term cost reductions become more difficult as the technology and production become more established and mature.
Sodium is not the end of lithium
For most electric vehicles, volumetric energy density is the first or second priority because the more space a battery cell takes up for a given energy density, the fewer cells you can fit under a vehicle, limiting range. For grid storage, the space taken up by battery packs does not affect their commercial viability and the priority is the cost per kWh per cycle. Commercial energy storage is about cost control, and this is where sodium-ion can potentially dominate other chemistries. The greatest potential in transportation applications for sodium-ion batteries exists wherever the energy density of lithium batteries is not fully utilized. This includes almost all electric cars with so-called standard range, that is, a reduced battery capacity compared to the more expensive models of the same construction. There, sodium batteries with higher charging speeds and less capacity loss at low temperatures could be a very interesting alternative. Above all, thanks to this alternative energy storage technology, lithium batteries will be available where they are truly indispensable.
