It’s momentum that makes technology so great. Even if you think a piece of hardware is as good as it can possibly be, the very nature of the industry is that someone, somewhere, is trying to make it even better. The industry simply doesn’t stand still. 

Consider e-bikes. If you actually take a moment to think about how miraculous the batteries that power these vehicles are, you’d probably assume we’re at the edge of what’s possible. These days, e-bikes are more powerful, lighter, and have a bigger battery capacity than several decades ago. 

But, as we’ve discussed, technology doesn’t stand still. There’s someone, somewhere, trying to make e-bike batteries even better, and one of the most intriguing of these technologies is sodium-ion. 

Hold on, what are sodium-ion batteries?

Technologically, sodium-ion batteries work in a broadly similar way to lithium-ion ones. In fact, the structure is the same, with the charging and discharging process involving the movement of ions between the cathode and anode. 

When charging the battery, electricity forces the ions to move from the cathode (the positive side) to the anode (negative side), where they are stored. When discharging (in other words, when you’re using the battery) this flow occurs in the opposite direction.

The difference between the two, though, comes from the materials used. 

In a sodium-ion battery, the anode is made from hard carbon, while the liquid electrolyte contains dissociated sodium salts. Lithium-ion batteries, on the other hand, often use a graphite anode with a liquid lithium electrolyte.

Of course, the science behind these two battery types goes deeper, but there’s one key thing to take into account: sodium-ion and lithium-ion batteries work in the same way, but with different materials.

The benefits of sodium-ion batteries

Now we can get to the good stuff: why we should be excited about sodium-ion batteries.

One of the most prominent positives is availability. Sodium is a cheap and ubiquitous material, consisting of 2.3% of Earth's crust, which means it’s roughly 400 times more abundant than lithium, which constitutes only 0.0065%.

Beyond availability, the price also makes a big impact. The estimated material cost for a sodium-ion battery could be as low as $80–100 per kWh, while lithium-ion is between $100–140 per kWh.

There are other benefits bundled in with sodium-ion, too. For example, its low-temperature performance is better, with the technology able to operate at -40°C, while lithium-ion begins to degrade at -20°C. On the temperature front, sodium-ion batteries also have a higher thermal threshold (around 300°C) than lithium-ion.

Then, there's faster charging. It takes about 15 min to reach 80% of capacity, while lithium-ion is closer to 30 minutes. 

On paper, it looks like we should all be using sodium-ion, but is that the case?

Pitfalls and growth potential

While it’s true that sodium is everywhere, nearly all existing global sodium‑ion manufacturing capacity is located in China, which is also expected to account for more than 95% of 2030 capacity. This means that although the material is abundant, the ability to actually turn this technology into batteries isn’t. That’s still geofenced.

And there are issues with other aspects of the technology too.

Lithium-ion is mature with a lot of support and optimisation behind it. This means that in the current market these batteries can deliver better energy density, have a more advanced supply chain, and cost less than sodium-ion. 

Of course, sodium-ion could be cheaper, but that requires the market to grow. It’s not all doom and gloom though, because this is likely to happen. It’s estimated that the global sodium-ion battery market will grow from $1.9 billion in 2025 to $13.21 billion in 2035. 

Although, right now, lithium-ion batteries are better value, there are companies trying to push the market forward. For example, CATL (the world’s largest battery manufacturer) had invested nearly 10 billion yuan (~$1.45 billion USD) in sodium battery R&D by 2025, and recently announced a brand new range of sodium-ion batteries. 

Sodium-ion batteries are coming, but it’s how they'll be used that’s particularly interesting.

The future and impact on micromobility

Currently, the biggest stumbling block for sodium-ion batteries is the energy density. Although new advances might be able to change this, common wisdom is that although sodium-ion batteries could be cheaper than lithium-ion, the amount of energy they can produce in proportion to their weight is lower.

This makes sodium-ion batteries particularly useful for situations where energy density isn’t a huge concern, think of huge battery plants, for example.

This doesn’t mean that it won’t impact elsewhere though. What we’ll likely see in micromobility and EVs in general is that sodium-ion becomes the choice of battery for more entry-level and budget models, areas where top-level performance doesn’t matter as much, and it’s all about just getting a vehicle into someone’s hands. The budget choice, if you will.

Ultimately, sodium-ion is a fascinating technology with huge amounts of potential. We could see advances come along that make it a real competitor to lithium-ion, but the likelihood is that this battery technology will instead carve out its own region of the landscape.

And that’s good for everyone. Advancing technology doesn’t just mean getting better when it comes to high performance, it also means offering once-premium experiences at entry-level costs — and that’s what sodium-ion has the potential to do.

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Cover image credits: Unsplash