Until now, the scope for sodium-ion batteries to replace the more familiar lithium-ion packs has seemed limited - but CATL has just shifted the odds dramatically.
The Chinese giant has unveiled the second generation of its sodium-ion battery, and the announcement feels like a genuine turning point. With an energy density of 175 Wh/kg, it even outperforms LFP lithium-ion batteries, while costing 7.5 times less. Set against Tesla’s cylindrical 4680 cells (NMC chemistry), the claim is even starker: 10 times cheaper.
With CATL already starting mass production, it was the perfect moment to invite Dr Helena Braga - a researcher at the Faculty of Engineering of the University of Porto (FEUP) - to explain what sodium batteries are and why they matter. She took to the stage at Auto Talks - Razão Automóvel’s new editorial format, launched at the ECAR Show - and helped us make sense of the technology and its potential.
Dr Helena Braga is widely recognised internationally for her work on next-generation batteries, particularly solid electrolytes - an approach that is also expected to transform future battery designs.
Her research drew the attention of John Goodenough (1922–2023) - Nobel Laureate in Chemistry and one of the inventors of the lithium-ion battery - and the two ultimately collaborated on solid-state battery research.
More recently, she presented an innovative battery that can recharge itself, based on sodium ions (salt). That breakthrough was the focus of a live Auto Rádio.
Sodium: a cheaper, more abundant alternative
Unlike conventional lithium-ion batteries, sodium batteries rely on an element that is a thousand times more abundant: salt. “There is far more salt than lithium on Earth,” Helena Braga said, also pointing out that both elements are found in the same salt flats - yet only 4% of what is extracted is lithium.
That availability goes a long way towards explaining the suggested cost: just 10 dollars per kWh. This is dramatically lower than roughly US$75/kWh for LFP batteries - the technology favoured by China’s automotive industry - or around US$100/kWh for Tesla’s cylindrical NMC 4680 cells (Source: Bloomberg NEF).
At Auto Talks, Dr Helena Braga added another reason why CATL’s sodium batteries can be produced so cheaply: they are anodeless, meaning there is no conventional anode (negative electrode) fitted during manufacturing.
Instead, the anode forms during the first charge cycle. That brings major benefits on the production line, because manufacturers no longer need controlled-environment rooms to install the anode - as is required with lithium-ion batteries. There are further reasons behind such a low price point, which you can watch/listen to in the video above.
Better performance and safer
Price is not the only advantage of CATL’s new-generation sodium batteries. They deliver the same energy density as LFP packs (around 175 Wh/kg) and are expected to reach similar longevity too: 10,000 charging cycles.
They also cope better with sub-zero temperatures (down to -40°C) and, because they do not include an anode, could be significantly safer. The explanation lies in the unusual architecture of CATL’s batteries, which the Portuguese researcher suspects may be solid-state, given the characteristics they appear to show.
This Auto Talks also gave Dr Helena Braga space to discuss the international landscape for innovation and battery manufacturing - where China is ahead of everyone else, including Europe. Why? It may be captured in just a few words:
“We are far too tied up in bureaucracy. Europe wants to accelerate on paper, but in practice it hesitates. China shows how it’s done: it invests, it produces and it takes risks.”
Dr Helena Braga, FEUP researcher
See you at the next Auto Talks
There is, then, no shortage of reasons to watch/listen to the latest Auto Talks - Razão Automóvel’s new editorial format - on the usual platforms: YouTube, Apple Podcasts and Spotify.
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