Sodium-Ion Batteries (SIB): Technical Analysis and State of the Market 2025
Feed the future, this is the great challenge we must meet. In a global context where the demand for energy storage is exploding, Sodium-Ion (SIB) technology is positioned as the most credible alternative to Lithium-Ion (LIB).
In this article, we offer an in-depth analysis of Sodium-Ion technology based on the work of Yves Choquette, an electro-chemist by training who has worked almost all of his career at the famous Quebec Crown corporation, Hydro-Québec. We go beyond marketing promises to look at chemistry, real-world performance in extreme weather conditions, and manufacturers’ strategies.
1. Context and Industrial Growth
Research on Sodium-Ion batteries (SIBs) has reached a stabilization stage since 2021, seeming to herald mass commercialization by 2027 according to the majority of experts. According to forecasts, the market is expected to grow by 27% annually, with production increasing from 10 GWh in 2025 to nearly 70 GWh in 2033, which would represent an increase of around 600%.
A major strategic advantage for manufacturers lies in the industrial tool. Indeed, the production of SIB cells can use the existing machinery of Lithium-Ion batteries with very few modifications, allowing for rapid deployment at a lower cost.
2. Chemistry at the Heart of Performance: Why a lower density?
SIB technology has some advantages observed in the laboratory, although they have not yet been massively demonstrated on a commercial scale. The main advantage is that this technology is associated with lower costs in terms of raw materials. Indeed, sodium is much less expensive than lithium because of its more abundant presence in the earth’s crust. The second main advantage is its greater power than Lithium-ion technology at very low temperatures (e.g. at -40°C). To better understand the reality of the performance of this technology, however, we must look at the atomic level.
- The Anode Challenge (Hard Carbon vs Graphite):
While lithium batteries use graphite (theoretical capacity of 372~mAh/g), sodium cannot fit effectively into them. SIBs therefore use “Hard Carbon” (HC), derived from biomass pyrolyzed at high temperatures. Although very stable, HC offers a lower theoretical capacitance (305~mAh/g), which results in a capacitance loss of about 18% at the anode alone.
- Overall energy density:
This chemistry results in an energy density that is 30 to 40% lower than that of LIBs. Currently, SIB cells offer between 140 and 160 Wh/kg, compared to 180 to 250 Wh/kg for lithium. This lower energy density can be observed directly at the level of the voltage of the unit cells. On the SIB cell side, the voltage is around 2.3-2.8V instead of 3.2V for lithium-iron phosphate type LIBs.
- Economic Advantage:
Despite lower density, SIBs could be 30% less expensive than LIBs by 2030. This advantage comes from the low cost of sodium, but also from the possibility of using an aluminum anode collector, which is much cheaper than the copper essential for lithium.
3. Cold Climate Performance: The Critical Nuance
SIB technology is often touted for its winter performance. However, an important technical distinction must be made between discharge and recharging.
- Discharge (Use): Performance is excellent, with a capacity retention of around 80% at -40°C, clearly outperforming conventional Lithium-Ion.
- Recharging: This is where the technical reality nuanced marketing. For the majority of current technologies, charging remains limited to a temperature range above -20°C.
- Practical involvement: For an application at -40°C, the battery will still have to be heated to accept the load, which represents an energy consumption to be considered in the sizing of the system.
4. Comparative Analysis of Manufacturers (State of the Art 2025)
The business landscape is dominated by very different technological approaches.
CATL: The race for density
The world leader is aiming for a density of 200 Wh/kg for its second generation in 2025, an impressive figure that would rival LFP chemistry.
- Innovation: CATL is developing hybrid battery packs, mixing Sodium and Lithium cells managed by an intelligent BMS. This makes it possible to combine the high energy density of Lithium with the cold performance of Sodium.
Meritsun & QNAS: Adapting existing formats
These manufacturers offer 12V batteries (e.g. 95R format) often using assembled cylindrical cells.
- Limitations: The use of cylindrical cells in these formats reduces volume optimization, resulting in a low density of about 84 Wh/kg for the full battery.
- Technical attention: The voltage range is very wide, ranging from 6V to 15.8V, which is much more extensive than the usual 12V standard and may require validation for some electronic equipment.
Natron Energy: Power first
Natron is distinguished by its “Prussian Blue” chemistry.
- Positioning: Their batteries are not aimed at long-term energy storage, but critical power (discharge in a few minutes). They offer a record cyclability of 50,000 cycles, but a low energy density, almost similar to supercapacitors.
HiNa Battery: The potential of extreme cold
HiNa seems to be one of the few players to offer a technology that potentially allows charging down to -40°C . With prismatic cells reaching 145 Wh/kg, they represent a very promising option for northern climates.
Conclusion and Recommendations
Sodium-Ion technology is real and offers undeniable safety (less flammable electrolytes) and long-term cost advantages. It is ideal for stationary applications where weight is less critical.
However, the technology remains “young”. Performance promises, including true cyclability and ultra-low temperature charging, vary greatly from one manufacturer to another.
The Volthium recommendation: It is imperative not to rely solely on the technical data sheets. Rigorous internal testing on cells and batteries is required to validate durability and real-world performance curves prior to any mass commercial deployment.
