Sodium-ion batteries – an important alternative to lithium-ion batteries

Yesterday´s introduction of sodium-ion batteries (SIBs) by Northvolt and Altris AB is the most promising alternative to lithium-ion batteries (LIBs) for next-generation rechargeable batteries. The advantages of sodium-ion batteries are their inexpensiveness and abundance, and their non-toxic and non-flammable properties. These batteries have good thermal stability, use less scarce materials, and are more sustainable.

Thus, sodium-ion batteries are an important part of our future fossil-free society. This new battery technology will play a vital role in society´s electrification. By capitalising on the benefits of each battery technology, we have a better chance of becoming fossil-free. Minimising our dependence on lithium will also enable a higher resilience in our society.

Sodium-ion batteries are ideal for large-scale stationary energy storage, small electric vehicles, or marine applications. On the contrary, lithium-ion batteries are better for applications where the battery must be light but possess a high energy density. Moreover, sodium-ion batteries work fine in cold temperatures, while lithium-ion batteries can lose as much as 50% of their stored energy when the temperature falls below zero.  

There is a lot of ongoing research and development on increasing the energy density of sodium-ion batteries. Recently, two master thesis projects on sodium-ion batteries have been undertaken at RISE, and a third is soon coming up.

The first work, “Towards Affordable Sodium-Ion Batteries: Mechanochemical Synthesis and Electrochemical Assessment of Na2FePO4F Cathode Material”, was conducted by Ratna J. and supervised by senior researchers Anwar Ahniyaz and Dhrubajyoti Bhattacharjya at Bioeconomy and Health Division, RISE Research Institutes of Sweden .

In this research, solid-state synthesis method was used to synthesise carbon-coated polyanion type of cathode active material (CAM), Na2FePO4F/C. The preliminary result shows that this type of sodium-ion battery can deliver a specific capacity of 74.24 mAh/g. 

The second master thesis, “The Development of Novel Cathode Material for Sodium-ion Batteries” (SIB), was conducted by Ananya Zaman and supervised by Anwar Ahniyaz and Dhrubajyoti Bhattacharjya .

In the research, both P2 and O3 type layered sodium-ion battery cathode active materials, NaFeMnO2, were synthesised using solid-state synthesis method. The preliminary results showed that as synthesised cathode active material (CAM), NaFeMnO2, synthesised by solid-state synthesis method, shows a specific capacity of  ~69 mAh/g.

A third RISE master thesis project on the synthesis of polyanion type of sodium-ion cathode active material for sodium ion battery application is planned for 2024. The project aims to examine polyanion type of cathode active material (CAM), Na3V(PO4)2F3. 

RISE hopes these three projects will contribute to developing a long-lasting and more sustainable battery value chain. 

To summarise, the news about Northvolt´s and Altris' collaboration on sodium-ion batteries is very positive for developing sodium-ion batteries in Europe. It is a big step towards developing a more sustainable energy storage system. Nevertheless, to achieve our climate goals, we must combine different battery chemistries and find the right mix. Here, cooperation is key.  

Author: Anwar Ahniyaz, 22 November 2023