December 2025, Martin Woudstra

Energy independence is high on the agenda of the European Union. The COVID19 pandemic and the war in Ukraine made the world realize that to be critically dependent on one or a few foreign countries for critical resources is very risky and could be a matter of national security.

The transition to renewable energy, which was already on its way to limit the rising temperatures, has more recently received a boost from the need for energy independence. After all, sun (and wind to a lesser extent) is available everywhere and is a great way to obtain energy independence.

The main challenge of these renewable energy sources (RES) is their intermittency. A lot of long duration energy storage (LDES) will be needed to make the system work as a whole. LDES will solve two problems in one go: provide electricity when there is insufficient RES coming in, and store excess incoming RES when it exceeds demand or electricity grid capacity. If energy storage capacity is not increased quickly, the addition of more solar and wind energy risks to be severely throttled.

From mobile consumer electronics via EVs to stationary energy storage, Li-ion batteries are the dominant chemistry with an established production and market. Sodium-ion is a promising emerging battery chemistry, starting to appear on the market.

The two main Li-ion battery chemistries are NMC and LFP. The high energy density NMC (Nickel-Manganese-Cobalt) batteries are the chemistry of choice for heavier and longer range EVs. The cheaper LFP (Lithium-Iron-Phosphorus) batteries have lower energy density and are becoming more popular for lighter or shorter-range vehicles, as well as for stationary storage. Na-ion batteries have still somewhat lower energy density than LFP and find similar applications, such as small EVs and stationary storage.

Na-ion batteries have some advantages compared to Li-ion batteries:

• higher charge/discharge rates
• better low temperature performance
• does not get destroyed at 0% charge
• can be stored and transported at 0% and 0V (safer)
• lower cost (expected, see below).

Many expect the cost of Na-ion batteries to become lower than Li-ion batteries, even though it is initially higher. The main reason is the 100x lower price of Na compared to Li. The question is: when will this happen? And how low will the price become?

The main advantage of Na-ion compared to Li-ion is the (expected) lower cost. The main technological drawback of Na-ion is its energy density. This makes Na-ion batteries particularly suited for stationary energy storage applications, because the more relevant parameter there is the cost per kWh per cycle, and energy density is much less important. But even for lighter or shorter-range vehicles, including 2- and 3-wheelers, Na-ion batteries could become serious competitors of Li-ion batteries.

The Li-ion battery industry is dominated by China in the manufacturing capacity, the production of battery manufacturing equipment and the processing of raw materials into battery-ready materials. This is creating an unprecedented supply chain concentration. This gives China strong geopolitical leverage, which is uses when it deems fit, as it has shown in the past few years in reaction to increased import taxes on Chinese goods by the US and Europe.

Even for Na-ion batteries China already dominates the early industrial value chain, driven by large players such as CATL and BYD. This is in part because the production process of Na-ion batteries is very similar to Li-ion batteries, which means many parts of the existing production infrastructure for Li-ion can be copied or re-purposed for Na-ion batteries. That is an advantage for all players, but since China is far ahead in production infrastructure, they can leverage that advantage at a higher scale. According to a Benchmark forecast, by 2030 95% of Sodium-ion battery cell production capacity will be in China, and only 1% in Europe.

Does this mean that Na-ion is in the same situation as Li-ion? Not fully. There are two important differences: raw material availability and scale.

While Li mining is limited to a few countries, Na is 1000x more abundant and readily available as soda ash and in salt mines in many places around the world. This allows for a more diversified and localized sourcing of Na compared to Li. This removes an important chokehold in the value chain. Once Ni has been removed from the cathode, Na-ion batteries do not contain any critical materials anymore.

Na-ion is still an emerging technology, and production capacity and demand are still much lower than Li-ion, which should lower the required scale-up speed for newcomers in the Na-ion space. And scale-up appears to be one of the major challenges in Europe.

The transition to renewable energy must continue at full speed. Sodium-ion batteries are a promising emerging energy storage technology both technologically and geopolitically. I expect it to become an important technology for stationary energy storage. I see a good opportunity here for Europe to invest early in both its development and production, in order to reduce external dependence as it builds its future energy infrastructure.

The perspectives presented in this piece are the author's personal views and are intended to contribute to constructive discussion and debate. Even though the author did his best to give a correct presentation of the factual content, no warranty is given of any kind, either expressed or implied, and the author accepts no responsibility or liability for any consequence of use of the publication or material in this article.