A few days ago, I saw a post on Reddit that asked a simple question: Will sodium-ion batteries replace lithium-ion batteries?
Some people were sure sodium-ion would take over. They kept saying it was cheaper and safer. Others weren’t convinced at all. They talked about lower energy density, shorter life, and how it still struggles in real-world use.
The more comments I read, the more I felt this wasn’t really about which battery is “better.” It was about something deeper. It was about where each technology truly belongs.
At Polinovel, we don’t believe sodium-ion is here to “take over. We see it as something that will exist alongside it, each serving different needs.
Here is our opinion.
At first, I thought the buzz was just hype. But the more I read, the more I saw that sodium-ion batteries are getting attention because it actually fixes some long-standing problems.
Sodium is one of the most abundant elements on Earth. You can get it from seawater and even from salt. That means it is not tied to just a few mining regions.
Lithium is different. Most of it comes from only a handful of countries. When politics change, mine production slows down, or EV demand jumps, prices move fast.
For long-term energy projects, this kind of uncertainty is a real problem.
If a system is meant to run for 15 or 20 years, stable materials are not just a purchasing detail. They are part of the technical risk.
Cost and materials are not the only reasons people are watching sodium-ion. Safety matters just as much.
In many real projects, batteries sit near people, inside buildings, or next to critical equipment. In those cases, safety is a basic requirement.
This is where sodium-ion shows a real advantage. Its chemistry has a higher thermal stability onset temperature and slower thermal runaway reaction kinetics, which means it is less likely to enter thermal runaway in both theoretical analysis and controlled testing.
However, realising this inherent safety potential in practice depends on more than cell chemistry alone. Real-world battery systems are far more complex.
The innate safety advantages of sodium-ion chemistry must be supported by equally robust system design. Components such as the Battery Management System (BMS), thermal management, and mechanical structure are all critical.
Only when "safer chemistry" and "a well-designed system" work in concert can the risks of fire and overheating be significantly minimised. This combination is precisely what makes sodium-ion solutions particularly compelling for safety-sensitive applications.
Sodium-ion batteries do not use lithium, cobalt, or nickel. These materials are costly and often linked to environmental and ethical concerns, including high water use and challenging mining conditions. Using more common elements helps ease pressure on these limited resources.
By using more common elements, sodium-ion batteries help reduce pressure on these limited resources. It also makes the supply chain simpler and easier to manage. This is also one of the reasons we at Polinovel are actively exploring and investing in sodium-ion technology—because long-term energy projects need stable, predictable supply chains, not fragile ones.
For large, long-term projects, this is more than just a nice bonus. If a system is expected to run for 20 years, choosing a battery made from stable and widely available materials is a smart way to reduce future risks.
It’s true—sodium-ion batteries solve some of the very issues discussed above. However, this does not mean they are ready to replace lithium-ion batteries across the board.
There are still basic limits, both in how they work and how they are used.
Energy density is the hard limit. This was one of the first problems that stood out. Sodium-ion batteries store less energy, which means you need a larger and heavier pack to get the same output.
Most sodium-ion cells today reach about 90–140 Wh/kg.
By comparison, LFP lithium batteries usually deliver 140–180 Wh/kg, and high-nickel lithium cells go even higher.
In practice, this means more weight and more space for the same amount of energy.
For a stationary system in a warehouse or near a solar farm, that may not matter much.
But once the battery has to move, it quickly becomes a problem.
In electric cars, drones, and power tools, every kilogram and every centimetre counts. When energy density is low, range and performance drop. And there is no easy way around that—it comes down to basic physics.
Lithium-ion batteries have been in real use for decades.
Because of that, engineers understand how they behave under heat, high power, and long-term cycling. There is a large amount of field data behind them. Sodium-ion does not have that history yet. Sodium-ion is still building that track record.
Many performance questions still need to be proven at scale, in real operating conditions, such as:
Long-term capacity retention under realistic duty cycles
Performance stability across wide temperature ranges
Robustness under frequent high-rate charge and discharge
Consistency under irregular operating conditions
This does not mean sodium-ion is unreliable.
It simply reflects a natural stage in the life of any emerging technology as it moves from laboratory testing to large-scale industrial deployment.
Sodium-ion’s current stage should be viewed not as a limitation, but as the foundation of its industrial future.
Consider the evolution of lithium-ion batteries: their reliability, safety standards, and global supply chains were not achieved overnight, but built over decades of mass production and iteration. Sodium-ion is now embarking on a similar journey from development to widespread commercialisation.
While scaling production remains a key focus, the technology’s commercial pathway is becoming firmly established. For forward-looking energy projects, this presents a strategic window: early adoption and evaluation today can secure long-term advantages in cost stability, material security, and supply chain resilience.
This marks not an end, but the beginning of a new industrial chapter.
In the end, the real question is whether people can trust the technology. Batteries are meant to last for years, not just a short time. In electric vehicles and grid storage, that means surviving thousands of charge and discharge cycles.
Lithium-ion batteries—especially LFP—already have a long history in real-world use.
They’ve been tested in commercial projects, over many years, and across a wide range of operating conditions.
Sodium-ion is still building that history—but it is moving fast. Early sodium-ion cells struggled with cycle life. That has started to change.
New cathode materials, such as Prussian white and layered oxide structures, have pushed performance much further.
Today, many sodium-ion cells can reach 3,000 or more cycles, which is much closer to what commercial LFP batteries deliver.
Large, long-term field data is still being built, but sodium-ion is no longer just a lab technology. It is now being tested in real projects.
Sodium-Ion vs Lithium-Ion: Key Differences at a Glance
| Aspect | Sodium-Ion Batteries | Lithium-Ion Batteries |
| Energy density | Lower | Higher |
| System size | Larger for same energy | More compact |
| Cost potential | Lower in the long term | Higher |
| Safety | Generally higher | Chemistry-dependent |
| Technology maturity | Early-stage | Highly mature |
| Typical use cases | Storage, backup power | EVs, industrial systems |
Put side by side, the differences are clear.
Sodium-ion is not a single replacement for lithium-ion. Lithium-ion still has the edge in energy density, maturity, and proven performance in the field. Sodium-ion, however, shows its strengths in safety, cost stability, and material availability.
Each battery type has its advantages, depending on the application.
Where Sodium-Ion Batteries Make Sense
It works best in systems where size and weight don’t really matter.
For things like battery Energy Storage, grid support, or backup power, long-term cost and safety are what people care about most. In these cases, stability and low fire risk matter more than high energy density.
Another big advantage is the supply chain. Sodium is easy to find. There is no real shortage. It also does not face the same political or supply risks as lithium or cobalt. For large projects planned to run for decades, that kind of supply security really matters.
Typical applications include:
Applications in cold storage environments, such as forklifts and other material handling equipment
Stationary systems where space and weight are not critical, such as energy storage systems
Engine starting applications, such as marine boats, automotive, and RVs
Where Lithium-Ion Batteries Still Dominate
When performance is critical, lithium-ion still makes more sense. In systems with tight space and weight limits, the options are limited. If power, portability, and efficiency all matter, high energy density becomes essential.
That’s where lithium-ion fits best.
In electric vehicles, extra battery weight means less range. In forklifts, power tools, and robots, size and weight directly affect how well they can work.
Lithium-ion also has a big advantage in experience. Its manufacturing, quality control, and battery management systems have been refined for years. Engineers understand how it behaves over thousands of cycles in real-world conditions.
Typical applications include:
Electric vehicles and light-duty mobility applications, such as golf carts, utility vehicles, and airport GSE
High-power material handling equipment, including forklifts, reach trucks, pallet jacks, and tow tractors
Mobile industrial equipment where compact size and weight efficiency are critical, such as aerial work platforms, floor cleaning machines, and AGVs
Applications with strict space and weight constraints
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When you place sodium-ion and lithium-ion in their real application contexts, the picture becomes much clearer. The question is no longer which technology will “win,” but which one fits the job in front of you.
In grid storage and backup systems, cost matters most. That’s where sodium-ion starts to make sense.
Once mobility, size, or power becomes important, lithium-ion is still the better option. At that point, it’s not about replacing one with the other. It’s about using each where it works best.
When you look at it this way, it stops being about replacement and starts being about using each technology where it fits best.
This is how we think about energy storage at Polinovel.
We don’t pick a battery type first and try to make it work everywhere.
We start by understanding how the system will actually be used. Then we select the battery technology that fits those conditions.
If you’re weighing sodium-ion against lithium-ion, contact us. We’re happy to walk through the differences using real data and real project examples.