Sodium-ion battery, a possible alternative?

Research on next-generation batteries represents a major challenge for the coming decade, particularly for the automotive industry. This technology is being researched internationally. Countries such as Japan, China, France, and the United Kingdom are looking for a plausible alternative to Li-ion. The sodium-ion battery is considered the most promising alternative.
Contrary to what one might think, sodium-ion technology has been known since the late 1980s, but it was set aside because the superiority of lithium-ion batteries was clear. Lithium offers a high energy density, and lithium ions are three times lighter than sodium ions. As a result, lithium-ion batteries have a very high energy density for low weight and volume.
Prototypes of sodium-ion batteries are being developed worldwide, particularly in France. The CNRS and Liten-CEA have partnered with about fifteen industrial players, including Renault, to form the French network for electrochemical energy storage (RS2E), which is dedicated to new batteries.
In Europe, the goal is to ensure research and development to commercialize sodium-ion batteries once the research has been completed.

What is a sodium-ion battery?

Just like a lithium-ion battery, a sodium-ion battery is a type of battery technology. Its operation differs little from the technology that dominates the battery market: lithium-ion. The chemical composition of the cathode and anode includes sodium and other metals. This alkali metal has a reducing power similar to that of lithium and shares many chemical properties. Sodium is a thousand times more abundant, found all over the planet, in seawater or as sodium chloride, unlike lithium, which is scarce on Earth. It is also the lightest metal known, which gives lithium-ion batteries their low weight and remarkable performance. The sodium-ion battery would therefore require less critical mineral.

How does a sodium-ion battery work?

Like lithium ions, sodium ions move from one electrode to another during charging and discharging. Its operation is therefore similar to that of a lithium-ion battery.

Difference between lithium-ion and sodium-ion batteries

Sodium-ion batteries have lower capacity and lifespan compared to lithium-ion batteries. These batteries do not contain nickel or cobalt in their composition. As sodium-ion technology is a variation of lithium-ion technology, French research has already demonstrated some interesting performance. The energy density of 90 Wh/kg remains lower than that of lithium-ion batteries.
The early lithium-ion battery had an energy density of 110 Wh/kg, but today it exceeds 200 Wh/kg. With the same technology base, improvements in sodium-ion batteries can be expected.

Environmental impact of sodium-ion batteries

Energy density still needs improvement, but the potential of sodium-ion batteries can also be evaluated from another perspective: the environment. As previously mentioned, sodium is abundantly available, so it would have a lower cost.

Applications of sodium-ion batteries

Sodium-ion batteries could be used for stationary energy storage produced by wind and solar farms, which would be their most relevant application. These batteries could also, in the future, power motorcycles and electric vehicles. For applications where power is not the primary criterion, sodium-ion batteries could be an economically interesting option.