What It Means For A Sodium-Ion Battery To Enter The Market

After years of experimentation, exploration and some very promising breakthroughs, a battery technology that had until now been confined to the laboratory is available for sale, with major implications for the rest of the manufacturing and toll processing world.

The battery company Northvolt announced in late November that they were able to add sodium-ion batteries to their portfolio of battery products over five years ahead of expectations for the maturation of the technology.

These batteries are rated at 160 Watt-hours per kilogramme, enough power density to be used for practical purposes, albeit still roughly 100 Wh/kg away from some high-nickel lithium-ion battery types.

However, what is vitally important is that this is the first battery of its time that does not rely on rare materials to make the battery. 

Whilst most lithium-ion batteries rely on some combination of nickel, manganese and cobalt alongside the lithium itself, all relatively rare metals, Northvolt’s battery uses “Prussian white”, made from sodium, iron and cyanide.

All three of these are far more plentiful, which makes them not only much cheaper but also more sustainable, not just compared to lithium-ion, but also compared to other similar sodium-ion technologies.

The main competing designs for sodium-ion have their advantages but fall just short of being an entirely practical replacement. Layered metal oxides are a very powerful alternative, but require less sustainable materials to work, whilst polyanionic batteries are sustainable but less capable.

At present, Northvolt has aimed its sodium-ion batteries squarely at the battery storage market, one where the energy density limitations are far less of a problem and the advantages of working in less-optimal temperature conditions without being dangerous far offset this drawback.

In China, where sodium-ion battery technology is being rapidly developed as well, the intention is for the technology to replace lithium-ion for smaller city cars, where the limited power and range are far less of a concern and the faster charging times provide immediate benefits.